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Mungbean residue effects on the growth parameters of a succeeding mungbean crop Bantilan, Roberto T. 1979

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MUNGBEAN  RESIDUE OF  EFFECTS  ON  A. S U C C E E D I N G  THE  GROWTH  PARAMETERS  MUNGBEAN :CROP  by  ROBERTO B.S.A.,  Mindanao  T.  Institute  Cotabato ,  A THESIS THE  SUBMITTED  REQUIREMENTS  the Faculty  of Technology,  PARTIAL FOR  OF  THE  FULFILMENT DEGREE  OF  SCIENCE  of Graduate  Studies  Department of PLANT  We  accept to  THE  this  1960  Philippines  IN  MASTER in  BANTILAN  SCIENCE  thesis  the required  as  conforming  standard  U N I V E R S I T Y OF B R I T I S H COLUMBIA November, 1979 (c) R o b e r t o T. B a n t i l a n  OF  In p r e s e n t i n g  this thesis i n p a r t i a l  f u l f i l m e n t of  the  requirements f o r an advanced degree a t the U n i v e r s i t y  of  B r i t i s h Columbia, I agree t h a t the L i b r a r y s h a l l make it  f r e e l y a v a i l a b l e for reference  and  study.  I further  agree t h a t p e r m i s s i o n f o r e x t e n s i v e copying of t h i s t h e s i s f o r s c h o l a r l y purposes may of my  be granted by  Department or by h i s r e p r e s e n t a t i v e s .  the Head  It is  understood t h a t copying or p u b l i c a t i o n o f t h i s t h e s i s f o r f i n a n c i a l gain written  s h a l l not be allowed without  permission.  Department of  The U n i v e r s i t y of B r i t i s h 2075 Wesbrook P l a c e Vancouver, Canada V6T 1W5  Date  / 4  TUIM^AJIZAJ  Columbia  /<?7f  my  ABSTRACT  I n v e s t i g a t i o n s o f mungbean (vigna (L.) W i l c z e k )  radiata  r e s i d u e s , which have been found t o have  adverse e f f e c t s and cause s u b s t a n t i a l y i e l d  reduction  on subsequent mungbean crops grown i n r a p i d r o t a t i o n , were u n d e r t a k e n t o determine t h e source o f p h y t o t o x i n and study i t s e f f e c t s on growth p a r a m e t e r s . There was no e f f e c t on p l a n t s grown i n pots o f s t e a m - s t e r i l i z e d s o i l t h a t had r e c e i v e d l e a c h a t e s  from  a c t i v e l y growing mungbean p l a n t s i n sand c u l t u r e , o r i n pots t h a t had r e c e i v e d l e a c h a t e s o f r o o t s and l e a v e s decomposing i n sand. E f f e c t s from r e s i d u e s o f p r e v i o u s mungbean crops were demonstrated when s u c c e e d i n g  mungbean crops were  grown such t h a t t h e i r r o o t s were i n d i r e c t p h y s i c a l contact w i t h the r e s i d u e .  P l a n t s grown i n s o i l i n w h i c h  r o o t - l e a f r e s i d u e mix had been i n c u b a t e d f o r one week p r i o r t o s e e d i n g were about 50% o f c o n t r o l i n t o t a l d r y w e i g h t a t any sampling  date.  T o t a l d r y w e i g h t was f u r t h e r  reduced t o about 40% when i n c u b a t i o n time was i n c r e a s e d t o t h r e e weeks.  S e p a r a t e e x p e r i m e n t s w i t h r o o t and l e a f  r e s i d u e s showed t h a t l e a f r e s i d u e s were about 12.3% more t o x i c t h a n r o o t r e s i d u e s on a p r o p o r t i o n a t e weight b a s i s . did  The c o m b i n a t i o n  n o t show a d d i t i v e e f f e c t s .  residue  o f l e a f and r o o t r e s i d u e s  iii  I n c o r p o r a t i o n o f t h e r e s i d u e s i n t o the s o i l p r e v e n t e d normal s e e d l i n g development.  P l a n t s growing  from r e s i d u e - t r e a t e d s o i l had more a s s i m i l a t e s a l l o c a t e d t o t h e l e a v e s d u r i n g t h e v e g e t a t i v e s t a g e compared t o those from r e s i d u e - f r e e s o i l .  During t h i s stage net  a s s i m i l a t i o n r a t e , r e l a t i v e growth r a t e , r e l a t i v e l e a f a r e a growth r a t e , and l e a f a r e a r a t i o became c o n s i d e r a b l y g r e a t e r than f o r c o n t r o l s .  Although, r e l a t i v e l e a f area  growth r a t e was i n c r e a s e d , w h i c h may have been due t o more a s s i m i l a t e s b e i n g a l l o c a t e d t o t h e l e a v e s , t h e g r e a t e r magnitude o f t h e i n c r e a s e i n r e l a t i v e growth r a t e o v e r t h a t o f the r e l a t i v e l e a f a r e a growth r a t e may account f o r the i n c r e a s e i n the value o f net a s s i m i l a t i o n rate.  T h i s would be p o s s i b l e i f t h e r e was a r e d u c t i o n  i n r e s p i r a t o r y l o s s e s , caused by t h e r e l e a s e o f a r e s p i r a t o r y i n h i b i t o r from t h e r e s i d u e s .  iv  TABLE OF CONTENTS  Page ABSTRACT  1  TABLE OF CONTENTS  1  *  L I S T OF TABLES  v  vi  L I S T OF FIGURES  v i i  ACKNOWLEDGEMENTS  ix  L I S T OF ABBREVIATIONS  X  INTRODUCTION  1  LITERATURE REVIEW  6  Allelopathy  6  Growth A n a l y s i s  16  MATERIALS AND METHODS  21  General  Management  Experiment  21  l.Root leachate t r a n s f e r  23  Nutrient solution  25  Donor p o t s  26  Recipient pots  26  Experimental  27  design  E x p e r i m e n t 2. L e a c h a t e t r a n s f e r r o o t and l e a f r e s i d u e s  from  decomposing  E x p e r i m e n t 3 a . S e q u e n t i a l mungbean c r o p p i n g w i t h w i t h r o o t and l e a f r e s i d u e s i n c o r p o r a t e d i n t o the s o i l Establishment of f i r s t Second crop Experimental  crop  27  28 28 29  design  29  V  Page Experiment 3b. Separate e f f e c t s o f l e a f and r o o t r e s i d u e s from p r e v i o u s mungbean crop C o l l e c t i o n o f data RESULTS  30 31 34  Leachate t r a n s f e r  34  S e q u e n t i a l cropping  38  E f f e c t s o f l e a f and r o o t r e s i d u e s  56  DISCUSSION  68  Residue e f f e c t s  68  Growth parameters  71  SUMMARY  79  REFERENCES  81  APPENDIX  86  vi  LIST OF TABLES  Table 1.  2.  3.  4.  Page Top w e i g h t (g/pot o f 4 p l a n t s ) o f mungbeans grown i n s o i l t h a t had r e c e i v e d l e a c h a t e s from mungbeans growing on sand c u l t u r e  35  L e a f a r e a (dm / p o t o f 4 p l a n t s ) o f mungbeans grown i n s o i l t h a t had r e c e i v e d l e a c h a t e s from mungbeans growing on sand c u l t u r e . . . .  35  Top w e i g h t (g/pot o f 4 p l a n t s ) o f mungbeans grown i n s o i l t h a t had r e c e i v e d l e a c h a t e s o f decomposing r o o t s and l e a v e s  36  2  L e a f a r e a (dm / p o t o f 4 p l a n t s ) o f mungbeans grown i n s o i l t h a t had r e c e i v e d l e a c h a t e s from decomposing r o o t s and l e a v e s  37  5.  Average p l a n t h e i g h t (cm) o f mungbeans grown i n s o i l t h a t had r e c e i v e d l e a c h a t e s from decomposing r o o t s and l e a v e s 37  6.  Summary o f c o n t r a s t between e f f e c t s o f t h e t r e a t m e n t s : w i t h vs w i t h o u t r e s i d u e , and t h e e f f e c t s o f t h e t r e a t m e n t s one- vs three-week incubation period  45  Comparison o f means o f a l l h a r v e s t s f o r 1-week and 3-week i n c u b a t i o n p e r i o d s w i t h l e a f and r o o t r e s i d u e s  48  Summary o f c o n t r a s t between t r e a t m e n t s : w i t h vs w i t h o u t l e a f r e s i d u e and t r e a t m e n t s : w i t h vs without root residue  59  7.  8.  9.  Dry w e i g h t r e d u c t i o n o f mungbean a t f i n a l h a r v e s t , i n p e r c e n t o f c o n t r o l , caused by t h e i n c o r p o r a t i o n i n the s o i l o f l e a f , r o o t and r o o t p l u s l e a f r e s i d u e s o f p r e v i o u s mungbean c r o p 69  vii  LIST OF FIGURES  Figure 1.  Page General arrangement and close-up view o f the r o o t l e a c h a t e t r a n s f e r experiment  24  Reduced s i z e o f mungbean s e e d l i n g s a t 7DAE grown i n cropped s o i l w i t h r o o t and l e a f r e s i d u e s i n c o r p o r a t e d and incubated f o r one week  39  Reduced c o t y l e d o n a r y l e a f expansion o f mungbean grown i n the r e s i d u e - t r e a t e d soil. 14 DAE  39  Stunted growth o f mungbean grown i n cropped s o i l w i t h r o o t and l e a f r e s i d u e s i n c o r p o r a t e d and incubated f o r one week. 14 DAE .  40  5.  The same treatment as i n F i g u r e 4 a t 28 DAE. . .  40  6.  Root development o f mungbean shown i n F i g u r e 4. . .  41  Root development o f mungbean a t 28 DAE o f the same treatment as i n F i g u r e 4  41  The e f f e c t o f r o o t and l e a f r e s i d u e s , i n c o r p o r a t e d and incubated f o r three weeks i n t o the s o i l , on the development o f mungbean s e e d l i n g s . . . .  42  The same treatment as i n F i g u r e 8 a t 7 DAE . . .  42  Normal s e e d l i n g development o f mungbean at 7 DAE . . .  43  Growth o f mungbeans i n cropped s o i l with l e a f and r o o t r e s i d u e s o f the previous crop i n c o r p o r a t e d and s o i l t h a t was l a i d f a l l o w , without r e s i d u e s  46  Comparison o f growth parameters o f mungbean grown on s o i l s w i t h r e s i d u e s vs s o i l s without r e s i d u e s  50  T o t a l dry weight, l e a f a r e a , r e l a t i v e growth r a t e , r e l a t i v e l e a f area growth r a t e , n e t a s s i m i l a t i o n r a t e , l e a f area r a t i o , and a o f the succeeding mungbean crop grown on s o i l c o n t a i n i n g l e a f and r o o t r e s i d u e s a f t e r a one-week i n c u b a t i o n . . .  52  2.  3.  4.  7. 8.  9. 10. 11.  12.  13.  viii  Figure 14.  Page Total dry weight, leaf area, r e l a t i v e growth r a t e , n e t a s s i m i l a t i o n r a t e , r e l a t i v e l e a f a r e a growth r a t e , l e a f a r e a r a t i o , and a o f t h e s u c c e e d i n g mungbean c r o p grown on s o i l c o n t a i n i n g l e a f and r o o t r e s i d u e s a f t e r a three-week i n c u b a t i o n period  54  The e f f e c t o f l e a f r e s i d u e on t h e t o t a l d r y w e i g h t , l e a f a r e a , l e a f , stem, and r o o t weights, l e a f weight r a t i o , s p e c i f i c l e a f a r e a r a t i o and l e a f a r e a r a t i o  60  The e f f e c t o f r o o t r e s i d u e on t h e t o t a l d r y w e i g h t , l e a f a r e a , l e a f , stem and r o o t weights, l e a f weight r a t i o , s p e c i f i c l e a f a r e a r a t i o and l e a f a r e a r a t i o  61  17.  R i c h a r d ' s ( f a c t o r ) diagram o f r o o t x l e a f interaction  64  18.  The e f f e c t o f l e a f and r o o t r e s i d u e s on r e l a t i v e growth r a t e and n e t a s s i m i l a t i o n r a t e o f t h e second crop o f mungbean  66  The e f f e c t o f l e a f and r o o t r e s i d u e s on t h e r e l a t i v e l e a f a r e a growth r a t e and R/Rjr a t i o o f t h e second crop o f mungbean  67  R e d u c t i o n o f d r y w e i g h t o f tops o f mungbean as i n f l u e n c e by date o f p l a n t i n g  72  Component d r y w e i g h t s as p e r c e n t o f t o t a l d r y w e i g h t o f s u c c e e d i n g mungbean crop as a f f e c t e d by t h e r e s i d u e and l e n g t h o f i n c u b a t i o n o f p r e v i o u s mungbean crop  75  Component d r y w e i g h t s as p e r c e n t o f t o t a l dry w e i g h t o f s u c c e e d i n g mungbean crop as a f f e c t e d by t h e l e a f and/or r o o t r e s i d u e s of the p r e v i o u s mungbean c r o p  76  15.  16.  19.  20. 21.  22.  ACKNOWLEDGEMENT  I would l i k e t o thank Dr. V.C. Runeckles, Chairman, Department o f P l a n t Science, Columbia, under c a r r i e d out,  The U n i v e r s i t y o f B r i t i s h  whose s u p e r v i s i o n t h i s research was  f o r h i s p a t i e n t guidance, c r i t i c i s m , and  a s s i s t a n c e i n the p r e p a r a t i o n  of this t h e s i s .  I wish t o thank the members o f my graduate committee f o r reviewing  this thesis.  I am g r a t e f u l t o the I n t e r n a t i o n a l Development Research Centre, Ottawa, Canada, f o r a s c h o l a r s h i p and f i n a n c i a l support f o r conducting my The  research.  a s s i s t a n c e o f Dr. G.W. Eaton i n the s t a t i s t i c a l  a n a l y s i s o f my r e s e a r c h  data i s a l s o hereby acknowledged  with g r a t i t u d e . To my c h i l d r e n , Teresa,  Roberto, E l e n a ,  Marilou,  M a r i e t t a and C h r i s t i n e (who was o n l y 19 months o l d when I came t o UBC), I deeply a p p r e c i a t e  t h e i r calm endurance  of the long absence o f t h e i r f a t h e r . F i n a l l y , I wish t o express my h e a r t f e l t g r a t i t u d e and  deepest a p p r e c i a t i o n t o my w i f e C r e s e n c i a  f o r h e r moral  support and perseverance i n c a r r y i n g o u t alone o u r f a m i l y r e s p o n s i b i l i t i e s i n my absence. to  Cresencia.  I dedicate  t h i s manuscript  LIST OF ABBREVIATION  cm  Sentimeter  DAE  days a f t e r emergence  dm  decimeter  g  gram  ID  inside  L  l e a f area of a l l leaves  LAR  l e a f area r a t i o  LWR  l e a f weight r a t i o  diameter  mg  milligram  mm  millimeter  NAR: E  net assimilation  rate  NPK  n i t r o g e n phosphorous p o t a s s i u m  OD  o u t s i d e diameter  PVC  polyvinyl  RGR: R  r e l a t i v e growth  R_  r e l a t i v e l e a f a r e a growth  chloride rate  Li  SLA  s p e c i f i c l e a f area  W  whole p l a n t w e i g h t  W_  dry l e a f weight  W'  d r y pod w e i g h t  WP  w e t t a b l e powder  W  dry root weight  W  d r y stent w e i g h t  p  c  (dried)  rate  (fertilizer)  1  INTRODUCTION  Multiple small  farmers  through  i n the t r o p i c s ,  maximum u t i l i z a t i o n  Sanchez, 1976). have d e t e r m i n e d patterns the  c r o p p i n g , as p r a c t i c e d by allows  o f space  crop  traditional  intensification  and t i m e  ( I R R I , 1973;  The i n h e r e n t p r o b l e m s i n t h i s the e v o l u t i o n o f the observed  among s m a l l f a r m e r s  i n the t r o p i c a l  practice cropping  regions of  world. Field  Cropping  experiments  undertaken  by t h e M u l t i p l e  Department o f the I n t e r n a t i o n a l R i c e  Institute  Research  (IRRI) a t L o s B a n o s , P h i l i p p i n e s have shown  the harmful  effects  of certain  legumes  S i k u r a j a p a t h y , 1974) and d r y l a n d r i c e Watanabe, 1978) on t h e s u c c e e d i n g  ( I R R I , 1973; ( V e n t u r a and  crop.  The g r e a t e s t  e f f e c t was d e m o n s t r a t e d t o be on s u b s e q u e n t p l a n t i n g o f t h e same c r o p ; t h a t i s , i n mungbean-mungbean, cowpeacowpea o r r i c e - r i c e has  (dryland) sequences.  b e e n shown t o be a d v e r s e l y a f f e c t e d by p r e v i o u s  mungbean o r cowpea c r o p s be  and cowpea h a s b e e n shown t o  a d v e r s e l y a f f e c t e d by a p r e v i o u s mungbean The  desirable the  Sweet p o t a t o  farmer  crop.  t o l e r a n c e o f mungbean t o d r o u g h t  makes i t a  c r o p i n a r i c e - b a s e d c r o p p i n g p a t t e r n where i s dependent on a v a i l a b l e  rainfall.  g r o w t h d u r a t i o n o f some o f t h e n e w l y d e v e l o p e d o f mungbean a l l o w s  two s u c c e s s i v e c r o p s  after  The s h o r t varieties r i c e , where  2  the a v a i l a b l e s o i l moisture i s not s u f f i c i e n t f o r a second crop o f r i c e . of  An understanding o f the mechanism  the r e s i d u a l e f f e c t of mungbean on a subsequent mung-  bean crop w i l l  thus be o f g r e a t b e n e f i t t o s m a l l farmers  s i n c e o n l y w i t h t h i s understanding w i l l  i t be p o s s i b l e  to develop ways to e l i m i n a t e or a t l e a s t circumvent the problem. E v a l u a t i o n of the e a r l i e r experiments  on r e s i d u e  e f f e c t s conducted a t IRRI and a t the U n i v e r s i t y o f the P h i l i p p i n e s tended t o p r o v i d e evidence s u p p o r t i n g an a l l e l o p a t h i c mechanism (Runeckles, 1974) of out  nematodes and s o i l f u n g i was (Runeckles, 1975).  although the r o l e  not c o n c l u s i v e l y  However, the experiments  ruled of  Ventura and Watanabe (1978) showed t h a t i n mungbeans the i n h i b i t o r y e f f e c t s appeared to be d i r e c t l y dependent on microorganisms  i n the s o i l , although i t was  whether the microorganisms  not  determined  caused d i r e c t damage t o the  r o o t system as s o i l - b o r n e pathogens o r caused the p r o d u c t i o n o f t o x i c substances i n h i b i t o r y to mungbean growth. The phenomenon of the harmful e f f e c t s o f some crop r e s i d u e s i s well-known t o farmers.  Farmers i n v o l v e d  i n c o o p e r a t i v e experiments w i t h IRRI i n the study o f r i c e - b a s e d cropping p a t t e r n s are r e l u c t a n t to i n c l u d e mungbean as a r o t a t i o n crop (IRRI, 1975)  e s p e c i a l l y when  the f i e l d i s intended f o r a tomato crop  l a t e r ; i n the  season.  3  In the phenomenon has are  left  on  pods a r e  experimental  the  and  i n the  removed.  leaves  soil. are  The  soil  crop  that  soil  roots  stems  and  decompose on  the  residue  the  the  surface  roots  and  problem.  also exists that materials  during  they p e r s i s t  subsequent crop  and  this  a r e n a t u r a l l y s h e d as  a c c u m u l a t e and  associated with  i n t o the  the  the  I t i s probable then t h a t only  released  o f the  leaves  at harvest;  leaves  However, t h e p o s s i b i l i t y  and  a t IRRI where  a l s o been o b s e r v e d , the  pods m a t u r e , and of  fields  the  a c t i v e growth o f  l o n g enough d u r i n g  the  the growth  to induce harmful e f f e c t s .  f o l l o w i n g p o s s i b l e mechanisms n e e d e d t o be 1) t h e  r o l e o f exudates  from a c t i v e l y  2)  the  r o l e o f decomposing r o o t  residues,  3)  the  r o l e o f decomposing l e a f  residues,  4)  the  i n t e r a c t i v e r o l e s o f both root  Hence,  investigated:  growing  and  are  roots,  leaf  residues. With these p o s s i b l e sources of phytotoxin, was  deemed e s s e n t i a l t o s t u d y  mungbean c r o p  on  mungbean c r o p  grown u n d e r v a r i o u s  transfer  and  the  f i r s t the  growth parameters o f  the  chemical  Hence a s e r i e s o f e x p e r i m e n t s was establish be and  that  the  a  succeeding  r a t h e r than  compounds  s u b s e q u e n t l y t o determine the  to  responsible.  undertaken i n order  phenomenon o b s e r v e d i n t h e  reproduced under e x p e r i m e n t a l  a  conditions of p o t e n t i a l  source of phytotoxicants,  attempt to i d e n t i f y  e f f e c t s of  i t  greenhouse relative  field  to  could  conditions, roles of  root  4  o r l e a f r e s i d u e s i n i n d u c i n g the Since p r e v i o u s  effect.  f i e l d s t u d i e s a t IRRI had been  e s s e n t i a l l y c o n f i n e d to the v i s u a l o b s e r v a t i o n s of impaired pated  of symptoms  growth and measurement o f y i e l d , i t was  antici-  t h a t the a n a l y s i s of growth throughout the growing  p e r i o d might r e v e a l how whether or not severe  the dynamics o f growth were a f f e c t e d ,  symptoms o r y i e l d e f f e c t s were  observed. An a d d i t i o n a l f a c t o r which r e q u i r e d i n v e s t i g a t i o n r e l a t e d t o whether the e f f e c t i n v o l v e d the t r a n s p o r t o f soluble phytotoxicants  (e.g. see R i c e , 1974)  or  was  dependent upon p h y s i c a l c o n t a c t between r e s i d u e s and  crop  r o o t s as has been found t o be the case i n some systems (e.g. see P a t r i c k e t a l . , 1963).  To achieve  o b j e c t i v e s , the f o l l o w i n g three experimental  these  various  approaches  were used: 1) The  hypothesis  t h a t the growing mungbean p l a n t  produces p h y t o t o x i c r o o t exudates was i n g the l e a c h a t e s  s t u d i e d by t r a n s f e r -  from the r o o t s of p l a n t s i n donor pots  into receptor pots. 2) The  hypothesis  i . e . , r o o t s and  t h a t o n l y the decomposing m a t e r i a l s ,  l e a v e s , produce t o x i c compounds t h a t are  water-soluble  and  t r a n s f e r a b l e was  s t u d i e d by t r a n s f e r i n g  the leachates  from decomposing roots and leaves from donor  to r e c e p t o r p o t s . 3) The  hypothesis  t h a t the r e s i d u e s have to be i n  c o n t a c t w i t h the r o o t s o f a succeeding  crop was  s t u d i e d by  incorporating directly  the d r i e d  and g r o u n d r o o t s  i n t o the pots o f the second  and/or l e  crop.  6 LITERATURE REVIEW  Allelopathy The  term a l l e l o p a t h y r e f e r s t o the d e t r i m e n t a l  d i r e c t o r i n d i r e c t b i o c h e m i c a l e f f e c t s o f one p l a n t (the donor) on the germination, growth, o r development o f another (receptor)  plant  (Putnam and Duke, 1978; Rice,  phenomenon, i t should be p o i n t e d i n t e r a c t i o n s between s p e c i e s .  out,  1974).  The  i s not l i m i t e d t o the  While the l i t e r a t u r e i s  r e p l e t e w i t h cases o f b i o c h e m i c a l i n t e r a c t i o n s between species, several plants  are a l s o r e p o r t e d  to exhibit  a u t o t o x i c i t y as i n the case f o r example o f hedge bindweed (Convolvulus  sepium)  (Sadhu and Das, and  timothy  Ventura and Watanabe, 1978), and a l f a l f a  ( N i e l s e n e t a l . , 1960) t o mention a few.  The recognized  1971;  (Quinn, 1974) , some v a r i e t i e s o f r i c e  i n f l u e n c e o f a l l e l o p a t h y i n a g r i c u l t u r e was as e a r l y as the 5th century BC (Putnam and  Duke, 1978).  But i t i s o n l y the l a s t twenty years  that  i t s s i g n i f i c a n c e has caught the i n c r e a s i n g a t t e n t i o n o f p l a n t s c i e n t i s t s and has l e d t o an i n c r e a s i n g number o f p u b l i c a t i o n s and reviews, and t o the t r e a t i s e by Rice A l l e l o p a t h y has been recognized  i n diverse plant  (1974).  habitats,  f o r example, i n deciduous f o r e s t (Lodhi, 1976) , i n o l d f i e l d succession and  (Rice, 1972; Wilson and Rice, 1968)  i n the a r i d C a l i f o r n i a chapparal  (Muller e t a l . , 1968).  Because o f the immensity o f the s u b j e c t o f a l l e l o p a t h y i n general,  I l i m i t the emphasis o f t h i s review t o the problems  t h a t a r i s e from crop  residues.  7  In  a g r i c u l t u r e , there are numerous r e p o r t s o f  the e f f e c t s of crop r e s i d u e s .  F o r example, N i e l s e n e t a l .  (1960) r e p o r t e d the e f f e c t s o f a l f a l f a , c o r n , o a t s , potatoes and timothy on the germination and growth o f s i x p l a n t s p e c i e s . P a t r i c k and Koch (1958) s t u d i e d the e f f e c t s of timothy, c o r n , r y e , and tobacco r e s i d u e s i n soil  on the r e s p i r a t i o n o f tobacco s e e d l i n g s .  McCalla  and Army (1961) r e p o r t e d e x t e n s i v e l y on the e f f e c t o f stubble-mulch  farming.  In the study by P a t r i c k and Koch (1958) , i t was found t h a t the substances capable o f i n h i b i t i n g the g e r m i n a t i o n , growth and r e s p i r a t i o n of tobacco s e e d l i n g s a r i s e under some c o n d i t i o n s of decomposition.  Species  and stage of m a t u r i t y o f p l a n t m a t e r i a l , water content and pH of the s o i l , and l e n g t h of decomposition p e r i o d were among the important f a c t o r s which i n f l u e n c e d the production of phytotoxic products. macerated undecomposed  Aqueous e x t r a c t s of  p l a n t m a t e r i a l s were not found to  be t o x i c i n t h e i r study. However, the germination and growth experiments of N i e l s e n e t a l . (1960) , u s i n g the standard germination technique i n sand, i n d i c a t e d t h a t aqueous e x t r a c t s o f crop r e s i d u e s of a l f a l f a , timothy, o a t s , corn and p o t a t o contained substances t o x i c to a t l e a s t one o f these crops and soybean. Compared to p l a n t s watered w i t h d e i o n i z e d water, e x t r a c t s from a l f a l f a r e s i d u e caused the g r e a t e s t r e d u c t i o n i n shoot and r o o t l e n g t h and i n percentage g e r m i n a t i o n .  They a l s o  8 caused the g r e a t e s t delay i n germination. was not as harmful as t h a t from a l f a l f a . potato e x t r a c t s were s t i l l the l e a s t .  Timothy e x t r a c t Oats, corn and  less harmful, with potato e x t r a c t  The crop s p e c i e s i n t h i s experiment  a l s o showed  marked d i f f e r e n c e s i n t h e i r t o l e r a n c e to the p h y t o t o x i c e f f e c t s o f the e x t r a c t s . to  The o r d e r o f d e c r e a s i n g r e s i s t a n c e  the p h y t o t o x i c e f f e c t s i n g e n e r a l was as f o l l o w s : a l f a l f a ,  c o r n , soybeans, peas, oats and timothy.  However, a l f a l f a ,  timothy, corn and oats r e s i d u e s were shown t o cause deleterious autotoxic e f f e c t s .  As i n d i c a t e d by the r a t i o s  of o b s e r v a t i o n s made on p l a n t s grown w i t h and without  extracts,  timothy showed the g r e a t e s t a u t o t o x i c i t y i n terms of r a t e and percentage  o f germination, r o o t and shoot l e n g t h .  A l f a l f a e x t r a c t caused the g r e a t e s t e f f e c t on r o o t growth but i t s e f f e c t on shoot growth and p e r c e n t germination was l e s s than t h a t of timothy. less  Corn and oats showed much  autotoxicity. The examples o f the e f f e c t s o f crop r e s i d u e s  r a i s e s the q u e s t i o n about the e f f e c t s o f stubble-mulch farming.  E x t e n s i v e s t u d i e s by M c C a l l a and a s s o c i a t e s  (McCalla and Army, 1961) have found t h a t w h i l e the p r a c t i c e has been demonstrated t o be o f p r a c t i c a l value i n r e d u c i n g s o i l e r o s i o n by wind and water, p l a n t r e s i d u e s c o n t a i n substances,and  microorganisms  i n the decomposing s t u b b l e  produce substances  t h a t may a f f e c t germination and growth.  Guenzy and M c C a l l a  (1966) i d e n t i f i e d s e v e r a l p h e n o l i c  compounds from stubble-mulch  f i e l d s , and o t h e r workers  9  have a l s o r e p o r t e d related  compounds w h i c h were shown  to various plant  a number o f p h e n o l i c a c i d s a n d o t h e r  crops  residues  from s o i l s  t o be p h y t o t o x i c  containing  decomposing  ( e . g . , B o r n e r , 1960; T o u s s o u n e t a l . ,  1968; Wang e t a l . , 1967; W h i t e h e a d , 1963, 1964; Chou a n d P a t r i c k , 1976; Chou a n d L i n , 1 9 7 6 ) . The  role  o f microorganisms i n the residue  p r o b l e m i s i l l u s t r a t e d b y t h e work o f C o c h r a n e t a l . (1977) w i t h The  study  Mats  residues  common i n e a s t e r n  stand  tillage  and p l a n t v i g o r i n t h e n o - t i l l a g e o r system o f wheat p r o d u c t i o n  (5-8 cmm t h i c k ) o f c r o p  o f Palouse  residues  silt  and s o i l  for wheat-seedling  loam s o i l .  t o d e t e r m i n e t h e numbers o f  growth.  i n S e p t e m b e r , 1975.  c o n d i t i o n s became  root  A l l residues inhibitors,  favorable f o r microbial  The r e s i d u e s were t e s t e d f o r t h e p r e s e n c e o f  p a t u l i n by t h i n be n e g a t i v e . the p h y t o t o x i n substance  f o r the succeeding  t o produce wheat-seedling  after  weekly  p h y t o t o x i c i t y and t h e r e s i d u e s  n i n e months, s t a r t i n g  only  bare  Water e x t r a c t s o f  f u n g i , b a c t e r i a , a n d pseudomonads  but  over  b e n e a t h them were b i o a s s a y e d  were p l a t e d b i w e e k l y  were f o u n d  i n the area.  residue o f l e n t i l s , pea,  w h e a t , b a r l e y a n d b l u e g r a s s . - were s p r e a d field  Washington.  was u n d e r t a k e n t o i n v e s t i g a t e t h e p r o b l e m  of reduced reduced  the crop  l a y e r c h r o m a t o g r a p h y b u t were f o u n d t o  No f u r t h e r a t t e m p t was made t o i d e n t i f y i n this  experiment.  p r o d u c e d by Peniciilium  Patulin i s a urticae  Bainer  found  to be common i n stubble-mulch t i l l a g e i n Nebraska (Norstadt and M c C a l l a , 196 8)  and has been suggested  to be the cause o f as much as 50%  i n h i b i t i o n o f shoot  growth i n wheat. G e n e r a l l y , the a l l e l o p a t h i c compounds i s o l a t e d from p l a n t m a t e r i a l s and  from s o i l belong  known as secondary p l a n t compounds.  to the group  These i n c l u d e  simple p h e n o l i c a c i d s , coumarins, t e r p e n o i d s , f l a vonoids,  a l k a l o i d s , cyanogenic g l y c o s i d e s and g l u -  sosinolates  (Rice,  1974;  Harborne, 1972).  (1974) proposed t h a t the probable  b i o s y n t h e t i c pathway  of s y n t h e s i s of the d i f f e r e n t c l a s s e s of chemicals  Rice  allelopathic  a r i s e through the a c e t a t e or s h i k i m i c a c i d  pathways. A l l e l o p a t h i c compounds are not unique chemically.  These compounds have a l s o been r e p o r t e d  to be i n v o l v e d i n s e v e r a l p r o t e c t i v e or f u n c t i o n s f o r the p l a n t  (Swain, 1977;  For example, p o l y s a c c h a r i d e s a c i d are suspected  R i c e , 1974).  acylated with  to be i n v o l v e d i n the  f u n c t i o n s of the p l a n t c e l l w a l l a g a i n s t microorganisms phytoalexins  (Wood and G r a n i t e , 1976)  (Deveral, 1972;  defensive  ferulic  defensive invading and  as  Swain, 1977), w h i l e  f e r u l i c a c i d has been i d e n t i f i e d as one o f the p a t h i c agents of decaying a lowland  f o r e s t community  rye r e s i d u e decomposition  l i t t e r o f dominant t r e e s i n (Lodhi, 1978), i n corn (Chou and P a t r i c k ,  and i n the p h y t o t o x i c e f f e c t s of decomposing residues i n s o i l  allelo-  (Chou and L i n , 1976).  1976) rice  and  According has  proven that  synthesized the or  as  chemicals are  t o Putnam and  a r e s u l t of involved  are  leaching  release  i n order  from  fog or  dew;  to a f f e c t other of  parts;  above-ground by  exudation or  from l i t t e r  or  litter accumulate  p l a n t s , must  t i m e , o r must be  t o have l a s t i n g  by  effect  constantly  (Rice,  t e c h n i q u e s have b e e n e m p l o y e d  1974). to  a l l e l o p a t h i c c h e m i c a l s which cause i n h i b i t o r y on  seed germination, p l a n t  (1974) has  many o f  1970).  plant  P h y t o t o x i n s o n c e r e l e a s e d must  Diverse  effects  shunted  Duke, 1 9 7 8 ) :  r e s u l t i n g from  f o r some p e r i o d  identify  are  (Whittaker,  through l e a c h i n g  s u f f i c i e n t quantity  released  bio-  from below-ground p a r t s ;  as m i c r o b i a l - b y - p r o d u c t s decomposition.  specific  brought about i n  toxins  rain,  toxins  toxins  for a  in plant  and  Putnam and  of water-soluble  of  Whether  metabolism  compounds f r o m l i v i n g  through a c t i o n o f  persist  stimulus.  plant  e f f e c t s are  ( R i c e , 1974;  of water-soluble  Rice  the  p o t e n t i a l l y autotoxic  exudation of v o l a t i l e  in  by  specifically  products of  vacuoles to prevent a u t o t o x i c i t y  s e v e r a l ways  by  end  one  I t i s known t h a t a l l e l o p a t h i c  Allelopathic  parts  external  i s a major unanswered q u e s t i o n  chemicals  by  an  are  chemical i n t e r a c t i o n s .  into  (1978) no  a l l e l o p a t h i c chemicals are  actually synthesized  function  Duke  the  discussed  included  treatise.  have r e c e n t l y p r e s e n t e d  development.  detailed descriptions  methods e m p l o y e d i n t h e  in his  g r o w t h and  cases of  Putnam and  Duke  of  allelopathy (1978)  a c o m p r e h e n s i v e summary o f  the  methodology of  allelopathy  of  in  allelopathy The  extraction of  through simple soaking,  are  sand or  then u s u a l l y  the  or  dish or  (Putnam and  roots  or  The  centrifuged  There are  of  soil  numerous  compounds  shoots,  Duke, 1 9 7 8 ) .  lengths  parts.  in flats  effects of extracted  g e r m i n a t i o n , growth o f symptoms  filtered  solution.  cold-water  for varying  live plant  in petri  in nutrient  of  review  most common method i s t h a t o f  before bioassaying  reports  in their  agroecosysterns.  time, of e i t h e r d r i e d or  extracts  or  studies  and  on  other  A v a r i a t i o n of  the  c o l d - w a t e r e x t r a c t i o n method i s t h a t o f m a c e r a t e d parts  placed  sponge t h a t  i n dishes supports  seeds are  sown.  assay are  c a r r i e d out  imply  that  release  demonstrated  germination  the  simulates  action of  containing  osmotic concentrations  and  a t pH  rain  indicator and  Many  However, A n d e r s o n and  compounds, s u c h as  solution  p a p e r on w h i c h  simultaneously.  that extracts  high  moistened c e l l u l o s e  Thus c o l d - w a t e r e x t r a c t i o n  compounds by  plant material.  addition,  a filter  cold-water e x t r a c t i o n  of  possibly  containing  plant  bio-  authors the on  fallen  Loucks  (1966) have  unknown o f non  natural  and  toxic  sucrose, r e s u l t i n depressions  early  seedling  development.  v a l u e s between 5 and  (25 m i l l i o s m o l a r )  has  In  sucrose  been demonstrated  reduce r a d i c l e growth o f  l e t t u c e by  (Chou and  Most o f  Young, 1 9 7 4 ) .  6,  the  of  as much as studies  in  to  75%  13 allelopathy  reported  consideration  the  i n the  Bioassaying  water  techniques  (Jackson  (Kommedahl and  and  by  means o f p e t r i  of materials  Hot  w a t e r and  autoclaving  increased  are o t h e r  e x t r a c t i o n process  The  use  permits  i s o l a t e d w h i c h may  include  dish or  pH  nutrient  boiling  solvents  (Friedman  methods w h i c h have b e e n  e l i m i n a t e m i c r o b i a l decay  be  phytotoxic. phytotoxic  substances that  of problems under n a t u r a l  of organic  are not  conditions  used.  while  into  solvents-in  a l a r g e r number o f  methods o f e x t r a c t i o n , t h e may  and  d i f f u s i o n o f s o l u b l e compounds  acqueous p h a s e .  into  , autoclaving  Ohman, 1 9 6 0 ) , o r o r g a n i c 19 71)  t o be  take  e x t r a c t e d by  W i l l e m s e n , 1976)  Horowitz,  the  not  bioassays.  and  allowing  do  r o l e s of osmotic concentration  o f e x t r a c t s used i n the  solution  literature  the  compounds  But,  i n a l l these  materials  isolated  n e c e s s a r i l y the (Putnam and  cause  Duke,  1978) . In d e t e c t i n g  the  presence of  from below-ground p a r t s , v a r i o u s employed. and  E a c h method u s e d  nutrients  test plants  so  attributable is  from b e i n g  giant corn.  (19 72)  by  the  The  toxicity.  to prevent water f a c t o r i n the  The  the  faberii the  the  Bell  be  and  e f f e c t s of  growth  growing o f donor  i n sand i n p o t s  of  most common method  non-competitive Herm.) on  growth  clearly  s t a i r s t e p s y s t e m u s e d by  system i n v o l v e s  recipient plants  attempts  substances  have been  o b s e r v e d e f f e c t s can  i n studying  foxtail(Setaria  techniques  a limiting  to chemical  exemplified  Koeppe  t h a t the  inhibitory  of  and  arranged a l t e r n a t e l y i n  14  stairsteps  so  that  t o r e c i p i e n t and nutrient Since in  back t o a r e s e r v o i r .  p h y s i c a l aspects of  species  exudation can  be  the  substances  donor p l a n t s  the  dishes,  in soil  or  b o t h d o n o r and  occurs  other  methods u s e d i n  from r o o t  on  or sand  are  Duke,  i n o r on  bioassaying Rice,  with  1972).  (Fay  fungi  materials  and  1968)  there  of  (Rice>  i n the  is difficulty  result  1974).  growing  factors  been u s e d i n e x a m i n i n g  (Wilson  f r o m decomplant  and  (Norstadt  and  materials before  Rice,  1968;  identified  decomposition of  by-products of  plant  fungal  McCalla,  1962;  i n d e t e r m i n i n g whether the  plant,  a d d i t i v e or  (b)  f o r s e l e c t e d time p e r i o d s  growth  comes from t h e  petri  growth  c e r t a i n s t u d i e s have  involved  and  evaluating  E i t h e r d r i e d or l i v e  soil  effect  an  f o r other  recipient plants  plant  in  i n s a n d and  growing  sand,  Duke, 1 9 7 7 ) ,  method has  have e v a l u a t e d  m e t a b o l i s m on  and  (a)  the  i n h i b i t o r y substances  Although  specific  one  1974).  plant materials.  placed  from  detecting  recipient plants  competition  release of organic  posing  day.  eliminated  exudates are:  times, leaching  A straightforward the  are  of phytotoxins  recipient plants  (Putnam and  of  directly.  leachates  e f f e c t s before  flow  donor  allelopathic effects resulting  for specific  evaluating  from  cycles per  competition  leaching  studied  Some o f inhibitory  and  The  t o a number o f  system, p o s s i b l e  from t h e  the  n u t r i e n t s o l u t i o n flows  solution i s set  the  this  the  the  microorganism, or  s y n e r g i s t i c e f f e c t of  both  is  toxic the  15  The  methodology  thus been v a r i e d . and  f o r the study of a l l e l o p a t h y  There  r e l i a b l e procedures  is still  a need t o develop s p e c i f i c  f o r the i s o l a t i o n o f  compounds, and b i o a s s a y t e c h n i q u e s t h a t and p r o v e  suspected  are e f f e c t i v e  t h e e x i s t e n c e o f t o x i c components more  definitively effects  has  than  observed  the e x t r a c t i o n i n nature.  methods u s e d  to simulate  16  Growth  Analysis  Numerous e x c e l l e n t r e v i e w s h a v e b e e n w r i t t e n this  subject  Radford  and  discussion  (1967) , R i c h a r d s  Growth a n a l y s i s tions  ( E v a n s , 1972)  plant's  (dW/dt)(1/W) be  (1971).  described the  by  a set of  equa-  performance of  =  (dW/dt)(1/L)  x  L/W  x  =  L/W  x  the  thus: LAR  SLA  i n t o i t s components: LWR W /W T  Li  where RGR  =  R e l a t i v e Growth Rate;  R  NAR  =  Net  (also c a l l e d  Assimilation  Unit  Relative  W  =  Whole p l a n t  L  =  Leaf area of  SLA  =  S p e c i f i c Leaf  LWR W  = =  Leaf Weight Ratio Leaf dry weight  .U  growth r a t e  comparison of  the  i s an  Ratio  i s defined the  ULR,  E  Leaf Area  matter already  RGR  Leaf Rate);  =  matter content of  o f dry  Rate  LAR  T  since  Sestak et a l .  X  L  dry  (1972) ,  NAR  =  T  found i n Evans  =  further divided LAR  be  representing  functional parts;  can  be  (1969) and  can  RGR  LAR  can  on  dry  weight  a l l leaves Area  as  the  plant with  present.  rate of  respect  I t s use  growth o f p l a n t s  of  increase  to the  permits  amount  the  different sizes,  o v e r a l l measure o f p l a n t  in  performance.  17  The  relative  growth o f  other plant parts)  a s s i m i l a t o r y apparatus  i s defined  similarly  growth r a t e o f dry m a t t e r a c c u m u l a t i o n 1971). the  W h i t e h e a d and  ratio of  relative is  the  Myerscough  relative  relative  considerable  leaf  area  (Sestak  increase  The  et a l . , that  (dry m a t t e r b a s i s ) ( a = R/R ,  R  i s a parameter  amount o f d r y w e i g h t i n c r e m e n t t h a t i s i n e x c e s s o f  the  a  When  =  the  The  the  the  later  production  the morphogenetic  efficient  1 a l l of  in maintaining plant.  an  photosynthetic  o v e r a l l morphological stages  o r g a n s , and  W(  a -1)  an  a s s i m i l a t o r y apparatus of  As  using  stepwise  imprecise.  the  A  etc.  b e e n done  more a c c u r a t e .  and  computing  facilities  But  time-consuming p r i o r  Parsons  and  1977).  from  taken  at  growth d u r a t i o n  of  c a l c u l a t i o n s have approach  (Radford,  1967)  t h i s was  very  t o the  has  availability  computer programs s u c h as  (1974;  structures  by  curve-fitting  multiple regressions  laborious  entail  size.  classically  o f time d u r i n g  and  b e e n shown t o be  o f Hunt and  finite  fruits,  a consequence, r e s u l t i n g  been i n a c c u r a t e  the  reproductive  from averages o f d i s c r e t e h a r v e s t s  intervals  the p l a n t .  form o f  up  of assimilates, i . e .  to produce f l o w e r s ,  Growth a n a l y s i s has  several  unit.  of morphogenesis which  thus u s u a l l y r e q u i r e a s u r p l u s  computation  proportions  dry w e i g h t accumulated i s used  of storage  i n order  a  T  of  the  o f t h e p l a n t as  of  to  indicates  amount r e q u i r e d t o m a i n t a i n  value  ,  a  where  T  a r e a growth r a t e ) ,  importance.  relative  (1962) r e p o r t e d  growth r a t e  rate of l e a f  t o the  (and  of  those  18  The  t e c h n i q u e o f growth a n a l y s i s ,  more t h a n  50 y e a r s  ago,  has  been used  since i t s inception to study  characteristics  and  matter  crops*grown under v a r i o u s  of f i e l d  to q u a n t i f y the accumulation  R o l l e r , N y q u i s t and components o f d r y m a t t e r  Chorush  t h a t RGR  of i n d i v i d u a l  etc.)  steadily  decreased  given  time  early  pod  increase  i n NAR.  increased  a b o v e - g r o u n d RGR  They i n t e r p r e t e d  due  i n NAR  and  RGR  primarily (19 60)  r o n m e n t , NAR  a p p l i c a t i o n on  to i n c r e a s i n g  of sugar-beet,  and p o t a t o d e c r e a s e d  sugar-beet  respectively.  NAR  an NAR  an growth  field-grown  LAR  fell  crop s p e c i e s .  soybeans,  t h e r e was The  time.  decline  During  was  by  20  and  50  NAR  percent  approximately  at similar  envi-  fell  5 weeks,  h a l v e d d u r i n g the subsequent w i t h time  a  leafiness.  o f b a r l e y remained  4 weeks b u t was and  to  p o t a t o , and b a r l e y  of  three  until  r e p o r t e d t h a t , under c o n t r o l l e d  l i n e a r l y with  L  declined  had  of population  towards m a t u r i t y .  approximately  R  any  fraction  t o the r a p i d  (1969) s t u d i e d t h e e f f e c t s fertilizer  Thome  RGR,  At  the i n c r e a s e i n  that, r e g a r d l e s s of treatment,  attributed  for  plant  stem,  fraction.  and  found  decline  soybeans,  (leaf,  o f the p h o t o s y n t h e t i c apparatus  Buttery  and  fractions  initiated  demand f o r a s s i m i l a t e s  the seed  density  plant  in field  f o r m a t i o n when i t p e a k e d c o n c u r r e n t l y w i t h  as a r e s p o n s e  of  dry  conditions.  as t h e p l a n t m a t u r e d .  the most r e c e n t l y Total  of  (1970) , i n s t u d y i n g  accumulation  found  t h e g r e a t e s t RGR.  growth  constant  weeks.  rates for a l l  19  Some s t r e s s influences reported area  f a c t o r s h a v e b e e n shown t o have  on g r o w t h p a r a m e t e r s .  contrasting  F o r example, L a s t  (1962)  t h a t t h e changes i n r o o t d e v e l o p m e n t and l e a f  c a u s e d by m i l d e w ( E r y s i p h e  associated with  graminis  D.C.) on b a r l e y  were  s i m i l a r d e c r e a s e s i n NAR. From 12 t o 68  2 days a f t e r i n o c u l a t i o n t h e mean NAR was 226.6 mg/dm /w 2 i n mildew-free controls series.  a n d 166.0 mg/dm /w i n t h e i n o c u l a t e d  I n young tomato p l a n t s  treatments o f short  duration,  subjected  Gates  NAR  a n d RGR was r e d u c e d d u r i n g  the  g r o w t h p a r a m e t e r s were g r e a t e r  upon r e w a t e r i n g . ratios  to w i l t i n g  (1955) r e p o r t e d  the period  that  of wiltingbut  than f o r c o n t r o l  During w i l t i n g , higher  plants  stem w e i g h t  and lower l e a f weight r a t i o s developed than i n t h e  c o n t r o l , whereas a f t e r w i l t i n g , l e a f w e i g h t r a t i o s were higher  t h a n stem w e i g h t r a t i o s .  indication final  harvest.  effects and He  that the recovery Gates  However, t h e r e  e f f e c t was c o m p l e t e  (1955) i n t e r p r e t e d t h e s e  as a t e n d e n c y t o w a r d s s e n e c e n c e d u r i n g  a return  t o a more j u v e n i l e c o n d i t i o n  concluded that  to m o d i f i c a t i o n s between p l a n t Tsiung  was no  upon  at the  treatment wilting rewatering.  t h e changes i n w e i g h t r a t i o s were due o f t h e normal p a t t e r n  of translocation  parts.  (1978) , i n a s t u d y o n t h e r e s p o n s e o f mung-  bean t o s o w i n g d a t e s i n t h e M a l a y s i a n B o r n e o s t a t e o f Sarawak  (4°07' N; 113°57*E) , a p p l i e d  growth a n a l y s i s t o c h a r a c t e r i z e among t h e s o w i n g d a t e s .  the technique o f  t h e marked g r o w t h  differences  A P h i l i p p i n e v a r i e t y , CES-55 u s e d  20  in  this  s t u d y , was  J u l y , A u g u s t and  after by  for a l l planting  70.  slow d u r i n g  RGR  growth, the  15  o f b e a n pods a t 51  the  first  by  and  20  days, followed  pod-setting  that  t o a peak a t day  25  behave s i m i l a r l y  the  d e c r e a s e was  negative value also was  As the  the  followed  by  increase a  changes an  except that  65.  The  decrease  increase  rapid, value  f r o m day  25  dropped to  a  in  RGR  i n LAR  (56%)  (36%).  f a r as  of  by a  at a slower rate but  a t day  of  attaining a negative  I can  determine,  there  a p p l i c a t i o n o f g r o w t h a n a l y s i s on  stress  a rapid  pattern  a t t r i b u t e d to a f a s t e r rate of d e c l i n e  t h a n i n NAR  similar  characterized  a t day 55  maturity  commenced, a t t a i n i n g  thereafter,  to  days  60.  (1978) f o u n d o u t  NAR  33  was  days and  also  smooth d e c r e a s e 65.  at  May, were  phenology  dates: flowering  i n a l l s o w i n g d a t e s was  f r o m day  there  m a t t e r a c c u m u l a t i o n was  maximum a t day Tsiung  Although  Dry  once f l o w e r i n g  in  i n plant  sowing, r i p e n i n g  day  b e g i n n i n g of March,  S e p t e m b e r , 1976.  marked d i f f e r e n c e s similar  sown a t t h e  allelopathy.  i s no plants  report  on  grown u n d e r  21  MATERIALS AND  The  e x p e r i m e n t s were c o n d u c t e d i n t h e  o f the Department o f P l a n t Columbia,  established  22°C  The  and maxima between 28° and  30°C.  l i g h t i n g was  12 h o u r s p e r day by means o f f i v e ( L u c a l o x ) lamps  of  British  temperature  such t h a t minima ranged  w i n t e r months s u p p l e m e n t a r y  Sodium-vapor  greenhouse  Science, University  a t a l a t i t u d e o f 49°16'N.  r e g i m e was 2 0 ° and  METHODS  between During  provided f o r  400-watt h i g h p r e s s u r e  a r r a n g e d i n a row  1.6  m  above t h e c e n t e r o f t h e f o u r - r o w p o t a r r a n g e m e n t . rows o f t h e p o t s were s p a c e d s u c h t h a t located within was  uniform.  lights  The  - 15  greenhouse s i t y was  i l l u m i n a t i o n m e a s u r e d 140  on a o v e r c a s t day was  f o o t - c a n d l e s on t h e n o r t h and  respectively. were 620  a l l t h e p o t s were  t h e 1.2m-wide a r e a where t h e l i g h t  a t 16:00  5 34 - 17  The and  intensities 610  - 15  518  intensity  cm b e l o w  - 13  south side  rows  o v e r t h e two m i d d l e  foot-candles.  foot-candles.  The  relative  the  and  rows  O u t s i d e the  a t t h e t i m e o f t h e above measurements t h e  156  inten-  humidity  f l u c t u a t e d between an a v e r a g e maximum o f 80% minimum o f  The  and  an  average  55%.  G e n e r a l Management 3 All The  river  t h e p l a n t s were grown i n 4 800 s a n d u s e d i n E x p t s . 1 and  thoroughly with water  until  cm  2 was  the washings  growing  medium.  washed were c l e a r .  The  22  soil  u s e d i n a l l e x p e r i m e n t s was  sterilized  potting  and o t h e r m a t t e r s out.  soil  t a k e n f r o m t h e steam-  supply i n the greenhouse.  larger  t h a n 1 cm d i a m e t e r were s c r e e n e d  Added amounts o f f e r t i l i z e r s  measured b a t c h e s  was MG50-10a of this  were s h o v e l - m i x e d i n  c o r r e s p o n d i n g t o one  In Experiments  Gravels  replication.  1 and 2, t h e mungbean c u l t i v a r  (green-seeded).  S i n c e an e a r l i e r  c u l t i v a r h a d shown w i d e v a r i a b i l i t y  used  planting  (some were  p u r p l e - b a s e d and t e n d t o be v i n y ) , h e a v y s e e d i n g r a t e s were u s e d and o f f - t y p e s were r o g u e d o u t 10 days  after  emergence.  Y e l l o w - s e e d e d MG50-10a was  3a and 3b.  A g a i n , two t y p e s were o b s e r v e d : d u l l  and g l o s s y y e l l o w .  used i n Experiments  The l a t t e r were s e l e c t e d  yellow  and were  o b s e r v e d t o be u n i f o r m . Maintenance inspection  o f a l l experiments  f o r moisture status  and h u m i d i t y e x t r e m e s , was  consisted of daily  o f the p o t s ,  temperature  and o c c u r e n c e o f p e s t s .  The  n o t a l l o w e d t o d r y up on t h e s u r f a c e n o r was  t o become w a t e r - l o g g e d .  A hygrograph  and  p l a c e d near the c e n t e r o f the greenhouse daily  h u m i d i t y and t e m p e r a t u r e  temperature  i t allowed  thermograph monitored the  The  desired  r a n g e was m a i n t a i n e d by means o f t h e a u t o -  matic temperature  c o n t r o l s o f the greenhouse.  was k e p t above 50% by p e r i o d i c the e x p e r i m e n t a l a r e a . propargite  ranges.  soil  sprinkling  Humidity  o f water  around  The p l a n t s were s p r a y e d w i t h  30WP a t 1.2 5 g / l i t e r ,  a miticide,  as m i t e  i n f e s t a t i o n s were o b s e r v e d a f t e r pod s e t .  Regular fumigations  o f the greenhouse  to control other  complex were s u f f i c i e n t  23  p e s t s , p a r t i c u l a r l y the greenhouse w h i t e f l y .  Experiment 1  The o b j e c t i v e o f t h i s experiment was  to determine  whether m a t e r i a l s leached from the r o o t s of mungbean p l a n t s growing i n sand c u l t u r e d u r i n g t h e i r growing p e r i o d and t r a n s f e r r e d c o n t i n u o u s l y to pots o f s t e a m - s t e r i l i z e d s o i l would accumulate and i n f l u e n c e the growth o f mungbean p l a n t s sown subsequently The experimental  i n the r e c i p i e n t  set-up was  soil.  composed o f : a) a  n u t r i e n t s o l u t i o n container with d i s t r i b u t i o n tubing; b) donor pots with sand as the r o o t i n g medium; c)  recipient  pots w i t h f e r t i l i z e d , s t e a m - s t e r i l i z e d p o t t i n g s o i l the r o o t i n g medium. arranged  as  The p o t s and n u t r i e n t supply were  as a s t a i r s t e p  system i n which each donor pot  leached i n t o a r e c i p i e n t pot by means of t u b i n g . The g e n e r a l arrangement i s shown i n F i g . l a and in  close-up i n F i g . 1 b.  The d i s t r i b u t i o n and r e g u l a t i o n  of  the n u t r i e n t flow to the i n d i v i d u a l pots were  i n the f o l l o w i n g manner: PVC a p p r o p r i a t e l e n g t h was  black tubing  connected  (1.27  accomplished cm ID)  a t one end v i a a check  v a l v e to the n u t r i e n t s o l u t i o n c o n t a i n e r ; the o t h e r was  connected  tygon  tube  v i a a p l a s t i c p i p e reducer to a  (0.64  tygon tube was  cm OD)  open at the o t h e r end.  long enough to serve as a  end  flexible This  "standpipe",  of  24  25  to balance  the p r e s s u r e head o f the n u t r i e n t s o l u t i o n i n  the c o n t a i n e r and t o a v o i d the problem o f a i r t r a p p e d w i t h i n the PVC f i n e PVC  tubing.  A l o n g the l e n g t h o f the PVC  tube,  l e a d e r tubes (1.2mm ID) were c o n n e c t e d , v i a  b r a s s i n s e r t c o u p l e r s , t o d e l i v e r the n u t r i e n t s o l u t i o n drop by drop t o the donor p o t s .  The  o u t l e t ends o f  the  l e a d e r tubes were f i x e d a t a h e i g h t t o d e l i v e r 6 drops per minute t o each donor p o t .  Two  l e a d e r tubes were  p r o v i d e d p e r pot t o d i s t r i b u t e the m o i s t u r e more e v e n l y on the s u r f a c e o f the r o o t i n g medium. Glazed ceramic pots (2.54  (17 cm d i a ) w i t h a d r a i n h o l e  cm d i a ) on the s i d e n e a r the bottom were used f o r  b o t h donor and r e c i p i e n t p o t s . A s e m i - f l e x i b l e p o l y propylene  tube (0.64  cm OD)  of appropriate length  was  f i t t e d t i g h t l y a t one end i n t o a h o l e d r i l l e d through a rubber s t o p p e r i n s e r t e d i n t o the h o l e i n the donor p o t . The o t h e r end o f t h i s tube was  plugged.  Two  l e a d e r tubes  were connected v i a b r a s s i n s e r t c o u p l e r s near the p l u g g e d end, t o d e l i v e r l e a c h a t e to each r e c i p i e n t p o t , as shown i n F i g . 1 b. Nutrient solution.  N u t r i e n t s o l u t i o n No.  1 as  d e s c r i b e d i n C a l i f o r n i a A g r i . E x p t . S t a . C i r . 347 (Hoagland and A r n o n , 1950) each e x p e r i m e n t a l was  unit.  was The  a l l o w e d to f l o w through  f l o w from the n u t r i e n t s u p p l y  r e g u l a t e d such t h a t the l e a c h a t e s o l u t i o n s were  d e l i v e r e d from the donor t o the r e c i p i e n t p o t s a t a r a t e w h i c h avoided e x c e s s i v e f l o w through the r e c i p i e n t p o t s t o waste.  The  amount o f s o l u t i o n t h a t d r a i n e d from the  26  r e c i p i e n t p o t was t o the  m i n i m a l and  the  capacity  r e c i r c u l a t e d back  of  I t was  expected t h a t the  sand would a l l o w  i n the  each p e r i o d of pots, with The  leachate  below) t h e two  donor p o t s .  v o l u m e s o f w a t e r t o wash o u t  pots u n t i l final  consumed.  stand  of  The  minimized  c o n t a m i n a t i o n by  s e c t i o n on  except The  f o r the  use  flushed  exudates.  a  controls.  of steam-sterilized  i n f l u e n c e of microorganisms  result.  p o t was  Seeding to a f i n a l  done 7 d a y s a f t e r t h e  l e a c h i n g p e r i o d , which approximates the between s u c c e s s i v e fertilizer  Recipient  and  remaining  of  and  excluded  weed s e e d s w h i c h m i g h t h a v e g e r m i n a t e d  i n f l u e n c e the  4 plants per  conclusion  used to water the r e c i p i e n t  4 plants/pot  the  from  d o n o r p o t s were s e e d e d t o  Recipient pots. soil  (see  d o n o r p o t s were d i s c o n n e c t e d  w a s h i n g s were s a v e d and  absor-  released  However, a t t h e  transfer  low  t h e maximum t r a n s f e r t o  r e c i p i e n t p o t s o f w h a t e v e r e x u d a t e was  the p l a n t s  and  not  system. Donor p o t s .  bing  was  plantings  i n the  (Osmocote, 14-14-14 NPK)  end  time  field. was  stand of  of the  interval Slow-release  added a t t h e  rate  3 of  74g/dm  since the  to insure  the  leachates  growth o f  the  the  had  b e e n consumed.  to  the  donor p l a n t s  t r a n s f e r continued  A separate as  of nutrients,  Two  a c c u m u l a t i o n were i n v e s t i g a t e d .  were t r a n s f e r r e d up  leachate  adequate supply  r e c i p i e n t p l a n t s were w a t e r e d f r o m t h e  stored  leachate  an  set with  no  end  of  the  ( a b o u t 28  i n the  c o n t r o l , f o r each l e a c h i n g  periods  I n one,  days).  In  period.  of  stage  the  ( a b o u t 70  donor p o t s  after  leachates  vegetative  to maturity  plants  tap  of  other, days).  served  27  Experimental  design.  Four treatments  o f two p e r i o d s o f l e a c h a t e a c c u m u l a t i o n control  f o r each  p e r i o d comprised  and one u n t r e a t e d  a replicate.  c o n s i s t e d o f two p o t s : d o n o r and r e c i p i e n t . five  replications  complete  block  Experiment  f o r a t o t a l o f 40 p o t s  was  experiment  used  the donor p o t s  Experiment  as i n t h e f i r s t  in a  were  randomized  except  r e s i d u e s which  that leached  1 were grown t o m a t u r i t y a f t e r w h i c h t h e t o p s T h e s e s e r v e d as t h e r o o t r e s i d u e d o n o r two o f t h e p o t s  i n a replicate  and i n c o r p o r a t e d i n t o one o f t h e b l a n k  p o t s o f t h e same r e p l i c a t e . r e s i d u e donor p o t s . two p o t s w i t h  These p o t s  The d o n o r p o t s t h u s  consisted of  r o o t r e s i d u e s , one p o t w i t h  leaf  residues  A l l the p l a n t  i n t h e s e p o t s were a l l o w e d t o decompose  week b e f o r e l e a c h i n g .  L e a c h i n g was  the donor pots  from  donor  s e r v e d as t h e l e a f  one c o n t i n u i n g c o n t r o l p o t , p e r b l o c k .  by w a t e r i n g  experimental  The p l a n t s o f t h e d o n o r p o t s i n  The l e a v e s f r o m  were p o o l e d  The same  experiment,  c o n t a i n e d decomposing  were c l i p p e d o f f .  residues  There  i n v o l v e d t h e l e a c h i n g o f decom-  o f r o o t s and l e a v e s .  into recipient pots.  and  treatment  2.  p o s i t i o n products  pots.  A  design.  This  system  consisting  f o r one  done f o r t h i r t y  days  t h e t a p j u s t enough t o  soak t h e r e c i p i e n t p o t s e v e r y o t h e r d a y .  The  control  28  d o n o r p o t was  t r e a t e d i n t h e same way  as t h e p o t s  with  residues. The same s o i l  r e c i p i e n t pots  source  fertilizer  was  experiment had the  as i n E x p e r i m e n t 1.  The same r a t e o f  a l s o added and s e e d i n g  4 p l a n t s / p o t was leaching period. was  i n this  done i m m e d i a t e l y Again,  to a final  after  stand o f  t h e 30-day  a randomized complete b l o c k  design  used.  E x p e r i m e n t 3a.  The  objective of this  whether d i r e c t  e x p e r i m e n t was  c o n t a c t between t h e r o o t s o f a subsequent  mungbean  crop  and t h e r o o t and l e a f  mungbean  crop  grown i n s o i l was  for  the second crop  two s t a g e s .  and  of f i r s t  in  the s e q u e n t i a l cropping  crop.  Pots  stand o f 4 plants/pot.  5 days a f t e r  sowing).  of soil  with  ( P o t s were  The same number  along with  of pots  the cropped  f a l l o w f o r the d u r a t i o n of the f i r s t  p l a n t s were grown t o m a t u r i t y , had  conducted  field.  s o i l were a l s o p r e p a r e d laid  I t was  i n order  added a t t h e same r a t e > a s i n E x p e r i m e n t 1 were  seeded t o a f i n a l  of  from a p r e v i o u s  a requirement  t o be a f f e c t e d .  Establishment  thinned  residues  T h i s approach s i m u l a t e d  as p r a c t i c e d i n t h e  fertilizer  t o determine  soil  crop.  The  i . e . , when most o f t h e pods  t u r n e d b l a c k , a f t e r w h i c h t h e l e a v e s were  collected,  29  d r i e d , g r o u n d , and corresponding  in  i n c o r p o r a t e d back i n t o  p o t s , which contained  the  soil  root  of  the  residues  situ. Second crop.  divided to provide a final and  stand  after  The  two  pots  o f cropped  soil  "incubation" periods.  o f 4 p l a n t s / p o t was  done a f t e r  three-week i n c u b a t i o n p e r i o d s .  A  were  Seeding  to  one-week corresponding  number o f f a l l o w p o t s were a l s o s e e d e d f o r e a c h i n c u b a t i o n p e r i o d to serve p l a n t s was 1)  monitored  14  by  as c o n t r o l s .  sampling  days a f t e r emergence  trifoliate  l e a v e s had  The  at four  growth o f  the  stages:  (DAE), when t h e  first  expanded;  2)  28  DAE,  flowering  stage;  3)  42  DAE,  pod-filling  4)  73  DAE,  maturity  —  stage; when 70%  o f t h e pods h a d  turned  black. Experimental of  4 treatments,  total  of  design.  4 sampling  80 p o t s .  Since  two  groups of p l a n t s w i t h  was  thought  the  The  dates,  experiment c o n s i s t e d and  5 replications,  treatments  a two-week age  t h a t a random a r r a n g e m e n t o f  w o u l d have b e e n d i s a d v a n t a g e o u s  were composed  a l l the  plot  as t h e main p l o t  and  sampling  dates  The were f i l l e d by time  as  vacant  the  s u b p l o t s was spaces  "filler  pots"  as t h e e x p e r i m e n t a l  pots  to the younger p l a n t s  by  treatments  of  difference, i t  because of p o s s i b l e shading design with  a  older plants. in  A  strips  t h e r e f o r e used.  c r e a t e d as s a m p l i n g  was  of p l a n t s seeded at the  plants.  split-  T h i s was  done same  done i n o r d e r  30  to minimize the e d g e - e f f e c t o f the vacant spaces by h a r v e s t i n g .  created  Border pots o f p l a n t s were a l s o p l a c e d  around the whole experimental  area.  Experiment 3b.  In t h i s experiment I s t u d i e d the growth o f a second mungbean crop, comparing s o i l which contained  both  r o o t and l e a f r e s i d u e s a g a i n s t s o i l which contained e i t h e r r o o t r e s i d u e s alone o r l e a f r e s i d u e s alone.  In t h i s way  the l e a f r e s i d u e e f f e c t was separated from the e f f e c t o f root residue. The  same g e n e r a l procedure  was f o l l o w e d as i n  Experiment 3a, i . e . , the e s t a b l i s h m e n t o f the f i r s t f o l l o w e d by the second crop.  The treatments  crop  were  e s t a b l i s h e d by d i v i d i n g the number o f pots o f cropped soil  and f a l l o w s o i l  into halves.  The l e a f r e s i d u e s from  one h a l f o f the cropped pots were i n c o r p o r a t e d i n t o the corresponding number o f pots o f the f a l l o w ( c o n t r o l ) soil.  T h i s made a t o t a l o f 20 pots w i t h r o o t s p l u s  l e a v e s , 20 pots w i t h r o o t s alone, 20 pots w i t h leaves and  20 pots without r e s i d u e s .  alone,  The second crop was seeded  a f t e r 12 days' i n c u b a t i o n o f the p l a n t r e s i d u e s .  The  pots were arranged i n a randomized complete b l o c k design c o n s i s t i n g o f 4 treatments,  4 sampling  r e p l i c a t e s , a t o t a l o f 80 p o t s .  dates and 5  31  C o l l e c t i o n of data  For the  a l lharvests,  crown o f t h e r o o t s .  t h e p l a n t s were c u t o f f a t  Leaves  were s e p a r a t e d f r o m t h e s t e m s ,  (including and l e a f  petioles)  a r e a measurements  were made i m m e d i a t e l y w i t h a H a y a s h i Denko AAM-5 a u t o m a t i c photoelectric integrating  a r e a meter.  Where r o o t  weight  was  r e c o r d e d , r o o t s were s e p a r a t e d f r o m s o i l  by means o f  5-mm  s c r e e n w i r e mesh and s u b s e q u e n t w a s h i n g  i n water w i t h  the  a i d of a fine kitchen  in  sieve.  paper towels b e f o r e bagging.  Washed  Leaves, r o o t s ,  and p o d s f r o m e a c h p o t w e r e b a g g e d b e f o r e oven d r y i n g  a t 70°C  o v e n - d r i e d samples  were c o o l e d  in  p l a s t i c bags  prior  r o o t s were  and l a b e l l e d  for at least  Each p l a n t  separately  expressed i n g/pot o f 4 p l a n t s .  The l e a f  2  of  was  converted  i n t o dm  2  and was  The sealed  part  and w e i g h t s were  area reading i n  2 e x p r e s s e d as dm / p o t  4 plants. For  Experiments  3a and 3b, SLA, LWR,  were c a l c u l a t e d by means o f a desk ulated  together with leaf  (W ), pod w e i g h t g  weight These the  separately  48 h o u r s .  (stem, l e a v e s , e t c . ) was w e i g h e d  cm  stems,  t o room t e m p e r a t u r e  to weighing.  blotted  (W), w h i c h  area  c a l c u l a t o r and were  p  (W ) R  weight  and t o t a l p l a n t d r y  i s t h e sum o f a l l component w e i g h t s . to analysis  o f t h e UBC Computing  of variance  Centre.  a n a l y s i s w e r e done on t h e d a t a g a t h e r e d f r o m 1 and 2 s i n c e  tab-  (L) , l e a f weight(W^) , s t e m  (W ), r o o t w e i g h t  v a l u e s were s u b j e c t e d  facilities  LAR v a l u e s  the f a m i l i a r  symptoms  No  through  statistical  Experiments  o f the e f f e c t o f  32  a previous  c r o p were n o t o b s e r v e d  r e c e p t o r p o t s were u n i f o r m Calculations and the  a  ascertain  from  the  But  3b were f i r s t Evans  s i n c e i t was  c a l c u l a t e d values  page 17)  was  the  curve-fitting  resorted to.  approach  dry weight  (L) w i t h  T h e s e c a n be  leaf  (1972)  area  represented  f (t)  =  a  L  =  f (t)  =  a' +  x  2  f r o m w h i c h R,  R^,  R  +  bt  b't + a  E and  =  d  f  l  (  +  t  dt  can be  sampling  ct  2  c't  +  dt  +  d't  2  derived  )  x  df (t) 2  E  =  d  f  l  (  f (t) 2  t  dt  a  =  R/R.  the on  changes i n mean  f (t)  dt  to  equations  )  f (t) 2  total  time ( t ) . as  following: =  and  (mentioned  ( S e s t a k e t a l . , 1971)  W  E  actual pattern  Cubic polynomial to the  and  L  p o i n t s along  (see A p p e n d i x 1) were f i t t e d (W)  R,  done w i t h  difficult  the  growth because o f l a c k o f sampling  growth c u r v e ,  appearance.  g r o w t h p a r a m e t e r s R,  3a and  e t a l . (1971).  the p l a n t s i n the  and  t r a d i t i o n a l method d e s c r i b e d by  Sestak  of  in size  of the  f o r Experiments  and  3  3  thus:  the  33  In  generating  dummy number was u s e d 3b. The in  Figures actual  the polynomial equations, a small  a t t=0 i n b o t h E x p e r i m e n t s  13 and 14 show t h e f i t t e d  and f i t t e d  Appendices  v a l u e s were e x a c t l y t h e r e were o n l y  In Experiment  3b t h e f i t t e d  three sampling p o i n t s . L  W, R  W, g  W, p  following  p a r a m e t e r s were  g.g ^".day  E  g.dm  -2  dm .dm 2  R a n d P^.  4 and 5.  convenience i n p r e s e n t a t i o n , the u n i t s o f  R  Calculation  The means o f t h e  and L f o r Experiment  3a and 3b a r e p r e s e n t e d i n A p p e n d i c e s  the  3a a r e p r e s e n t e d  t h e same as t h e a c t u a l v a l u e s s i n c e  a c t u a l v a l u e s f o r W, W ,  For  curves f o r W and L.  values f o r Experiment  2 a n d 3.  3 a and  of  o  ^  -1 .day  2  .day  ^  changed:  to  mg.g ^".day ^  to  mg.dm  to  -2 -1 .day  cm .dm . d a y 2  2  was b a s e d o n t h e o r i g i n a l  *  units of  34  RESULTS  The  c u r r e n t use  o f the  to the harmful  effects  ( t h e d o n o r ) on  the g e r m i n a t i o n ,  term a l l e l o p a t h y r e f e r s  of higher  p l a n t s o f one growth, o r  species  development  of p l a n t s of another  (receptor) species  Duke, 1 9 7 8 ) .  f o l l o w i n g d i s c u s s i o n s t h e use  the of  In  the  term i s extended t o apply a previous  ment o f t h e  crop  crop  and  to the d e t r i m e n t a l  ( t h e d o n o r ) on  succeeding  (Putnam  t h e g r o w t h and  ( r e c e p t o r ) o f the  of  effects develop-  same s p e c i e s .  Leachate t r a n s f e r .  E x p e r i m e n t 1 was  u n d e r t a k e n i n an  demonstrate whether w a t e r - s o l u b l e healthy  intact  and  be  may  The visible  and  of  to m a t u r i t y .  The  show any  between t h e  weight of  Inspection of of treatment  28-day and  obvious,  c o n t r o l s from the tops  o f the r e c e p t o r p l a n t s are p r e s e n t e d  significant effects  soil  toxicity.  r e c e p t o r p l a n t s d i d not  2 respectively.  from  rhizosphere,  made t o a c c u m u l a t e i n a  d i f f e r e n c e s from the  germination areas  loss  to  t o x i n s a r e exuded  r o o t s o f mungbean, a c c u m u l a t e i n  t r a n s f e r r e d and  medium w i t h o u t  attempt  these  per  se,  time  and  of  leaf  i n Tables  data and  reveals  1 no  no d i f f e r e n c e s  70-day l e a c h i n g p e r i o d s .  35  Table 1.. Top weight (g/pot o f 4 p l a n t s ) o f mungbeans grown i n s o i l t h a t had r e c e i v e d l e a c h a t e s from mungbeans growing on sand c u l t u r e . Harvested at m a t u r i t y . ( 7 0 DAE)  Treatment  Replication  Mean  1. 28-day l e a c h i n g  22.0  30.4  23.2  33.6  31.6  28.2  2. C o n t r o l f o r T r e a t . No. 1  33.6  31.6  22.0  30.4  21.2  27.8  3. 70-day l e a c h i n g  33.2  28.0  24.0  32.0  24.8  28.4  4. C o n t r o l f o r T r e a t . No.3  31.6  23.4  22.1  30.3  33.4  28.2  2 Table 2. Leaf area (dm / p o t o f 4 p l a n t s ) o f mungbeans grown i n s o i l t h a t had r e c e i v e d l e a c h a t e s from mungbeans growing on sand c u l t u r e . Harvested a t m a t u r i t y . ( 7 0 DAE).  Treatment  Replication  Mean  1. 28-day l e a c h i n g  20.9  27.9  21.9  30.4  27.1  25.6  2. C o n t r o l f o r T r e a t . No. 1  29.4  27.8  19.8  26.4  18.8  24.4  3. 70-day l e a c h i n g  28.9  24.9  18.7  28.2  20.2  24.2  4. C o n t r o l f o r T r e a t . No. 3  28.3  20.9  18.9  27.6  30.2  25.2  36  Experiment water-soluble posing  2 a t t e m p t e d t o show i f t h e r e a r e  phytotoxins  residues The  t h a t w o u l d l e a c h o u t o f decom-  a f t e r death.  d o n o r p l a n t s w h i c h were grown t o m a t u r i t y  E x p e r i m e n t 1 were u s e d i n t h i s or  leaf  residues  s a n d medium  were a l l o w e d  and l e a c h a t e s  which the r e c e p t o r  as  receptor  leaves visible  3, 4 and 5  respectively of  a t the f l o w e r i n g  accumulation  from  stage,  decomposing  As i n E x p e r i m e n t 1, t h e r e were no  d i f f e r e n c e s between t h e t r e a t e d p l a n t s  controls, Similarly,  and t h e  f r o m t h e t i m e o f emergence t o h a r v e s t the data  treatment. data  Tables  and h e i g h t s  plants harvested  and r o o t s .  root  were t r a n s f e r r e d i n t o s o i l i n  areas  a f f e c t e d by l e a c h a t e  Their  t o decompose i n t h e o r i g i n a l  p l a n t s were grown.  show t o p w e i g h t s , l e a f the  experiment.  in  r e v e a l no s i g n i f i c a n t  date.  effects of  However, i t i s o f i n t e r e s t t o n o t e t h a t t h e  suggest  a greater  effect  of leaf rather  than  root  residues.  T a b l e 3. Top w e i g h t ( g / p o t o f 4 p l a n t s ) o f mungbeans grown i n s o i l t h a t h a d r e c e i v e d l e a c h a t e s o f d e c o m p o s i n g r o o t s and l e a v e s . H a r v e s t e d a t f l o w e r i n g s t a g e . (35 DAE)  Treatment  ;  2.  "  3. C o n t r o l  Mean  2  3  11. 0  15.2  11.6  16. 8  15. 8  14. 1  l e a v e s 16. 8  15. 8  11.0  15. 2  10. 6  13. 9  16. 6  14.0  12.0  16. 0  12. 4  14. 2  1 1. Decomposing  Replication  root  4  5  37  T a b l e 4. L e a f a r e a (dm / p o t o f 4 p l a n t s ) o f mungbeans grown i n s o i l t h a t h a d r e c e i v e d l e a c h a t e s o f d e c o m p o s i n g r o o t s and l e a v e s . Harvested a t f l o w e r i n g s t a g e . (35 D A E ) .  Treatment  Replication 1  1. Decomposing 2.  "  Mean  2  3  18. 6  16.4  17.1  18. 2  18. 8  17. 8  l e a v e s 21. 4  19.6  14.2  18. 2  14. 2  17. 5  19. 6  16.2  13.9  19. 8  20. 4  18. 0  root  3. C o n t r o l  4  5  T a b l e 5. A v e r a g e p l a n t h e i g h t (cm) o f mungbeans grown i n s o i l t h a t had r e c e i v e d l e a c h a t e s o f decomposing r o o t s and l e a v e s . H a r v e s t e d a t f l o w e r i n g s t a g e . (35 D A E ) .  Treatment  1. Decomposing 2.  "  3. C o n t r o l  Replication  root  Mean  38. 4  38. 1  38. 7  36. 9  37. 8  38. 0  l e a v e s 41. 0  41. 3  34. 3  37. 8  32. 4  37. 4  42. 0  37. 8  36. 3  40. 6  37. 5  38. 8  38  Sequential  cropping.  Since showed t h e on  the  typical  receptor  does n o t  involve  phytotoxins medium. closely  With  the  plants,  this  residues  length  of  of  from the  growing  of  the  as  to the  field  second  crop  f i r s t , with  f i r s t c r o p worked  the  into  p r i m a r i l y designed to  root  and  and  of  the  cropped s o i l  l e a f residues  residue  to  had  compare  of  f i n d out  an  a  into  previous i f the  influence  on  problem. i n both cropped  t r e a t m e n t s showed o b s e r v a b l e  typical the  Those p l a n t s  symptoms o b s e r v e d  cotyledonary  g r o w t h was  and  o c c u r e d e s s e n t i a l l y a t the  a f t e r emergence.  was  problem  release  i s o b s e r v e d , the  A s e c o n d o b j e c t i v e was  incubation  u n i f o r m and  of  the  donor  as p r a c t i c e d i n  succession  3a was  Germination  the  conditions  g r o w t h o f mungbeans i n f a l l o w s o i l  mungbean c r o p .  the  leached  the  seedbed.  w h i c h were i n c o r p o r a t e d  the  deduced t h a t  easily  problem  Experiment the  be  the  Where t h e  root  i t was  e f f e c t of  experiments  i n view, I attempted to simulate  as p o s s i b l e  and  leachate-transfer  a mere s t r a i g h t f o r w a r d  e s t a b l i s h e d i n quick  leaves  the  symptoms o f t h e  which can  cropping. is  none o f  stunted  severely  leaves  same t i m e .  differences  i n the  was  field.  was  But  immediately  grown i n c r o p p e d s o i l  ( F i g s . 4 and  reduced  fallow s o i l  Thus,  showed  expansion  i n h i b i t e d ( F i g s . 2 and 5)  ( F i g s . 6 and  and 7)  root  3),  development  i n a l l the  plants  39  F i g u r e 2. Reduced s i z e o f mungbean s e e d l i n g s a t 7 DAE grown i n c r o p p e d s o i l w i t h r o o t and l e a f r e s i d u e i n c o r p o r a t e d and i n c u b a t e d f o r one week. Note the e a r l y development o f the f i r s t t r i f o l i a t e leaves i n the no-residue soil.  F i g u r e 3. R e d u c e d c o t y l e d o n a r y l e a f e x p a n s i o n o f mungbean grown i n t h e r e s i d u e t r e a t e d s o i l . 14 DAE.  40  F i g u r e 4. S t u n t e d g r o w t h o f mungbean grown i n c r o p p e d s o i l w i t h r o o t and l e a f r e s i d u e i n c o r p o r a t e d a n d i n c u b a t e d f o r o n e week. 14 DAE.  F i g u r e 5. The same t r e a t m e n t as i n F i g u r e 4 a t 28 DAE. G r i d l i n e s i n t h e above p h o t o g r a p h s a r e 15.24 cm a p a r t .  41  Figure  6.  R o o t d e v e l o p m e n t o f mungbean shown i n F i g u r e  F i g u r e 7. R o o t d e v e l o p m e n t o f mungbean a t 28 DAE o f t h e same t r e a t m e n t as i n F i g u r e 4.  4.  42  of  the  cropped s o i l .  cropped s o i l base of  3 days a f t e r  about  the  Examination of  s t e m was  thickened  root d i d not  develop  seedlings  the  of  Total  s t e m s , r o o t s , and  and  contrasts  following a)  one-  b)  pods),  =  l  3-week  tap  compared t o  normal  areas,  (leaves,  LAR's, LWR's  and  Comparisons the  1/2(T  1  incubation +  2  vs w i t h o u t 1/2(T  =  Control  T^  =  Treatment with  T  =  Control  2  4  Table  of  the  effects  period).  +  T )  for  of  the  +  T );  x  4  =  1/2(T  2  +  T );  4  4  of  residues;  3-week i n c u b a t i o n  of  residues;  analyses  of  variance  d r y w e i g h t s , and  done  contrasts  (one-  r o o t and  weights of  the  and  plants.  incorporation of  vs  leaf  three-week residues  hence the The  the  of  residues  is  and  incubation  severely  total  extent  on  the  (with vs w i t h o u t r e s i d u e s )  component w e i g h t s  the  3  3  reduce the  receptor  1/2(T  1-week i n c u b a t i o n  treatments  Obviously,  =  T .  treatments the  2  T^-  for  total  vs  3  6 summarizes t h e  component and  x  residue  Treatment with  x  vs  T )  =  c a u s e d by  as  to a n a l y s i s of variance.  =  where T^  the  leaf  3  effects  9)  the  t r e a t m e n t e f f e c t s were done i n  vs  with x  T  c u r l e d and  the  manner:  X  the  of  and  w e i g h t s , component w e i g h t s  SLR's were s u b j e c t e d  from  (Fig. 1 0 ) .  same age dry  seedlings  emergence showed t h a t  8 and  (Figs.  the  dry  the  reductions  presented  43  CKorpeo FALLOU)  SOIL  3  Resieue  OF PLANT 6  P4HS AFTIR  & DAHS AFTl*.  SefPW6 O8-/5  IV/T-H  sen.  UlFFftf IUOH RAJ ION  08-  - 7&  IttDfAi*  /S -78  F i g u r e 8 . The e f f e c t o f r o o t and l e a f r e s i d u e s , i n c o r p o r a t e d and incubated f o r three weeks i n t o the s o i l , on the development o f mungbean s e e d l i n g s . 3 DAE (6 days a f t e r s e e d i n g ) . Note the s l i g h t l y thickened and c u r l e d b a s a l p o r t i o n o f the h y p o c o t y l i n c o n t r a s t t o the untreated s o i l ( f a l l o w ) .  3 I'trm  mo  . IVIT-H J RATIO A  OF  PLANT  ft  7  DAY*  AFTf*  Figure 9 . The same treatment as i n F i g u r e 8 a t 7 DAE. Note the abnormal development o f the primary r o o t . Above m a g n i f i c a t i o n i s twice t h a t o f F i g . 8 .  44  F i g u r e 10. Normal s e e d l i n g development o f mungbean a t 7 DAE. M a g n i f i c a t i o n i s 1:4.  45  i n Figure 1 1 .  The  l i n e a r r e g r e s s i o n l i n e s are h i g h l y  significantly different presented  i n Appendix  (Table 6 ) .  The  primary data  are  4.  Table 6. Summary of c o n t r a s t s between e f f e c t s of the treatments: with vs without r e s i d u e , and the e f f e c t s of the treatments: one- vs three-week i n c u b a t i o n p e r i o d .  with vs without residue  Variables  incubation  one- vs three-week incubation  X  residue  interaction  T o t a l dry weight  **  **  ns  leaf  **  **  ns  l e a f weight  **  **  ns  stem weight  **  ns  *  r o o t weight  **  **  ns  pod  **  *  ns  LAR  *  ns  ns  LWR  *  ns  ns  SLA  ns  ns  ns  area  weight  ** S t a t i s t i c a l l y s i g n i f i c a n t at 1% l e v e l , * S t a t i s t i c a l l y s i g n i f i c a n t at 5% l e v e l . ns N o n - s i g n i f i c a n t  Incubation  of the r e s i d u e s  f o r up to three weeks  appears to enhance i t s d e l e t e r i o u s e f f e c t s  on  the  Figure  1 1 . Growth of mungbean i n cropped s o i l w i t h  l e a f and  r o o t r e s i d u e s of the previous  incorporated  ( • ), and  without r e s i d u e s leaf  (W ), L  stem  ( o ). (W ), g  crop  i n s o i l t h a t was  laid  T o t a l dry weights  root  (W ),  and pod  R  fallow,  (W), (W ) p  weights are expressed i n g/pot o f 4 p l a n t s .  Leaf  2  area  (L) i s expressed i n dm /pot of 4 p l a n t s .  p o i n t represents  the mean across  incubation  Each  periods.  For each parameter, the slopes of the l i n e a r r e g r e s s i l i n e s are h i g h l y s i g n i f i c a n t l y  different.  47  DAYS  AFTER  EMERGEN  C€  48  accumulation o f dry matter i n a l l p a r t s of the p l a n t on  leaf  (Table  area 6).  (Table This  7).  lack of e f f e c t  stem w e i g h t p r o b a b l y interaction  The o n l y  exception  i s stem  and weight  of incubation period  accounts f o r the s o l e  on  significant  b e t w e e n i n c u b a t i o n p e r i o d and r e s i d u e  (Table 6 ) .  T a b l e 7. C o m p a r i s o n o f means a c r o s s a l l h a r v e s t s f o r 1-week and 3-week i n c u b a t i o n p e r i o d s w i t h l e a f and root residues.  Incubation one week Treated Control  Variables  (g/pot Total  dry weight  period t h r e e weeks Treated Control  of 4 plants)  9.20  20.80  5.03  18.76  leaf  weight  3.54  7.53  1.66  6.69  stem  weight  2.17  5.08  1.07  5.35  root  weight  0.93  2.12  0.46  1. 89  2.57  6.08  1.84  4. 84  pod  weight  2 (dm / p o t o f 4 p l a n t s ) leaf  area  10.51  Since no m a j o r  variance  i n t e r a c t i o n s between t h e two  t h e mean v a l u e s one-  the a n a l y s i s o f  20.80  o f the  and t h r e e - w e e k  d e r i v e d growth  5.08  20.45  (Table  6)revealed  treatment sets, parameters f o r  i n c u b a t i o n s were i n i t i a l l y  the  compared  49  to  t h e means o f t h e c o r r e s p o n d i n g  The  effects of residues  differences The  exception  rate, by  occuring  there  during  leaf  total  area  leaf  residues those  areas  were  o f growth.  on r e l a t i v e  area  throughout  be p o i n t e d  therefore growth. plants  of the plants  e a r l y peaks  Thus d u r i n g accumulated  plants  of the delay the f i r s t  little  considerably Figures  greater  through  than  made b e t w e e n  those  13 a n d 14 p r e s e n t  o n mean v a l u e s  since  only.  f o r R, E ,  appreciable  so that  these  i n relative 14 d a y s growth  of the controls.  t h e a c t u a l and curves  equations  1 ) . No s t a t i s t i c a l  treatments  than  o f growth,  relative  L a n d LAR a n d t h e f i t t e d  (Appendix  curves  the subsequent  , based on t h e polynomial  W and L  based  itself  less  i n the onset o f  dry matter,  revealed  a  the rate  ( F i g . 12) a r e  14 d a y s  nevertheless  and  period.  by F i g . 13 and 14.  i n the f i t t e d  slow growth during  f o r W,  the growing  c o n s i s t e n t l y and s u b s t a n t i a l l y  the result  data  growth  grown i n t h e p r e s e n c e o f  terms, t h e i r  rates  leaf  out that, while  f o rresidue-grown  01  the major  the e a r l y stages  o f t h e c o n t r o l s , as r e v e a l e d  and  shown, w i t h  12).  e x p a n s i o n may h a v e b e e n s t i m u l a t e d , t h e  The LAR,  (Fig.  i s a c o n s i s t e n t s t i m u l a t i o n caused  the presence of residues  However, i t should of  are clearly  i s the effect  i n which  controls  f o rR  f  fitted R , L  derived f o r  comparison can be  the fitted  curves  were  E  50  Figure  12.  C o m p a r i s o n o f g r o w t h p a r a m e t e r s o f mungbean  grown on  s o i l s with  residues  ( o  R  —  mg  —  cm  E  —  mg  LAR  —  dm  a  ~  R  These are  L  ).  residues  Units  2  2  R/R  used -1  .  g  .  dm  .  dm  .  g  -2 -2  ( • ) vs  soils  are: .  , -1 day  .  day  .  day  -1 -1  - 1  L  averages across  incubation  periods.  without  51  DAYS  AFTER  EMERGENCE  Figure  13.  relative rate  T o t a l dry weight growth r a t e  (R), r e l a t i v e  (R^), n e t a s s i m i l a t i o n  ratio  (LAR) and  grown on s o i l after 11  (W), l e a f  o  rate  area leaf  a one-week i n c u b a t i o n .  L  area  (E),leaf  o f the succeeding  containing leaf  (W ), growth  area  mungbean  crop  and r o o t r e s i d u e s U n i t s as f o r F i g u r e s  and 12.  Fallow  :  • - a c t u a l d a t a ; o- f i t t e d  data;  solid  Residue  :  • - a c t u a l data; °- f i t t e d  data;  dashed  line. line.  DAYS  AFTER  EMIRGENCE  Figure  14.  Total  growth r a t e leaf a  dry weight  (R), net  containing  succeeding leaf  and  incubation period.  leaf  assimilation  a r e a growth r a t e of the  (W),  (R ), leaf T  area  rate  (L), relative  (E), r e l a t i v e  area r a t i o  mungbean c r o p grown on  root residues after U n i t s as  Fallow  :  A - actual data;  Residue  :  •-  a c t u a l data;  and  soil  a three-week  f o r F i g u r e s 11 A-  (LAR)  and  12.  fitted  data;  solid  fitted  data;  dashed  line. line.  55  56  A comparison of F i g u r e s 13 and 14 r e v e a l s t h a t the two  s e t s of c o n t r o l p l a n t s behaved s i m i l a r l y .  they demonstrated s i m i l a r o v e r a l l growth curves weight and The  Thus  f o r dry  l e a f area i n terms of both form and magnitude.  same i s g e n e r a l l y t r u e f o r the d e r i v e d growth parameters,  although  there are g r e a t e r d i f f e r e n c e s r e v e a l e d with  to the magnitude of some o f the v a l u e s .  respect  This i s probably  the r e s u l t of s l i g h t d i f f e r e n c e s i n the growing c o n d i t i o n s to which the p l a n t s were s u b j e c t e d , because o f the two-week d i f f e r e n c e i n time of seeding.  The o n l y parameter showing  a markedly d i f f e r e n t t r e n d over time i s i n both s e t s , the o v e r a l l t r e n d i s f o r slightly  a a  .  However,  to d e c l i n e  from a value c l o s e to 2, i . e . the demonstration  of a s h i f t from a q u a d r a t i c towards a l i n e a r r e l a t i o n s h i p between W and  L.  I n s p e c t i o n of F i g u r e s 13 and 14 a l s o shows t h a t the enhancement of the d e r i v e d growth parameters w i t h i n the e a r l y stages o f growth caused by r e s i d u e s was  greater  f o l l o w i n g 3-week i n c u b a t i o n .  E f f e c t s of l e a f and r o o t r e s i d u e s .  With the e f f e c t o f combined l e a f and r o o t r e s i d u e s amply demonstrated i n Experiment 3a, i t became o f i n t e r e s t to f i n d out which o f the two the g r e a t e r t o x i c i t y .  r e s i d u e s was  the source  of  With t h i s i n f o r m a t i o n , i n v e s t i g a t i o n  57  of the mechanics o f p h o t o t o x i c i t y and the i n d e n t i f i c a t i o n of the p h y t o t o x i c compounds r e s p o n s i b l e could be focussed on a s p e c i f i c  source.  Experiment 3b was designed  t o compare the separate  e f f e c t s of l e a f r e s i d u e s w i t h those o f r o o t r e s i d u e s .  The  experiment was g e n e r a l l y the same as Experiment 3a with the a d d i t i o n o f treatments i n which only l e a f o r r o o t r e s i d u e s were i n c o r p o r a t e d i n t o the s o i l .  Because o f an  e a r l y problem o f e s t a b l i s h i n g the p l a n t s , which was due  t o u s i n g too c o l d water f o r watering  s t a r t , some pots had t o be d i s c a r d e d .  probably  the pots a t the  As a r e s u l t o n l y  three samplings were p o s s i b l e , i . e . , 30, 52, and 75 days a f t e r emergence. As with Experiment 3a, t o t a l dry weights, component weights  ( l e a v e s , stems, r o o t s and pods),  leaf  areas,  LAR's, LWR's and SLR's were s u b j e c t e d t o analyses o f variance.  Comparisons and c o n t r a s t s o f treatment e f f e c t s  were done i n the f o l l o w i n g manner:  a)  with vs without K  1  b)  =  1/2(T  x  + T ) 3  with vs without x  residues vs  x  2  =  1/2(T  4  +T ) ;  1/2 ( T  4  + T^) ;  2  root residues  3  =  =  mean o f l e a f r e s i d u e treatment;  =  mean o f r o o t r e s i d u e  T^  =  mean o f l e a f and r o o t r e s i d u e treatment;  T.  =  mean o f c o n t r o l  where T^ T  2  1/2 ( T  leaf  2  + T ) 3  vs  x  4  =  treatment;  58  The  effects  on g r o w t h w h i c h  o f the mixed l e a f  root residues  had b e e n o b s e r v e d i n E x p e r i m e n t  were a g a i n d e m o n s t r a t e d  3a  and were shown t o be more p r o -  nounced i n the case o f the l e a f the  and  root residue treatments.  r e s i d u e treatments  T a b l e 8 summarizes  the  c o n t r a s t between the t r e a t m e n t s w i t h o r w i t h o u t residues on  leaf  and t r e a t m e n t s w i t h o r w i t h o u t r o o t r e s i d u e s  t h e components o f g r o w t h and  can be  than  clearly  seen  t o t a l dry weight.  that the h i g h l y  significant  It  effects  of  r e s i d u e s a l r e a d y p r e s e n t e d i n T a b l e 6 were m a i n l y  to  the presence of l e a f The  of are  residues.  differences  r e s i d u e s on  i n the e f f e c t s  o f t h e two  t h e g r o w t h o f a s u c c e e d i n g mungbean  graphically  i l l u s t r a t e d i n F i g u r e s 15  and  5.  of  r e s i d u e s on  of the presence o f l e a f  a r e a and t h e components o f d r y w e i g h t in  F i g . 15.  results  In r e l a t i v e  the weight  t h a t , because dry  weight  and LWR  depicted are  leaf  area or weight the g r e a t e s t  leaf shown  at  each  reduction i s  However, i t s h o u l d a l s o be on  area, or l e a f weight, both  s l i g h t l y but  the d i f f e r e n c e s  reduced t o n o n - s i g n i f i c a n c e  noted  total LAR  significantly.  regard to the e f f e c t s  i n F i g . 16,  magnitude  are c l e a r l y  o f the r e l a t i v e l y g r e a t e r e f f e c t  are i n c r e a s e d With  terms,  of roots.  t h a n on  The  case the presence o f l e a f r e s i d u e s  i n a decrease i n l e a f  harvest. in  In each  The  types crop  16.  primary data are p r e s e n t e d i n Appendix the e f f e c t s  due  of root residues at a l l harvest dates  in relation  to the  effects  59  T a b l e 8. Summary o f c o n t r a s t s b e t w e e n w i t h o u t l e a f r e s i d u e and t r e a t m e n t s root residue.  Variables  Total  w i t h vs without Leaf residue  dry weight  treatments w i t h vs w i t h vs without  w i t h vs without Root r e s i d u e  **  *  leaf x root Interaction  Leaf  area  **  *  Leaf  weight  **  *  Stem  weight  **  ns  *  Root  weight  **  **  **  **  ns  ns  LAR  **  ns  *  LWR  **  ns  **  SLA  ns  ns  ns  Pod  weight  **  —  Statistically  significant  a t 1%  level.  *  —  Statistically  significant  a t 5%  level,  ns  —  Non-significant  ns  dm ^/g/pot 4|— .  drr /g/pot 3r 2  SLA  LAR  0130  52  75  0 30  DAYS'  AFTER  52  EMERGENCE  F i g u r e 15. The e f f e c t o f l e a f r e s i d u e on t h e t o t a l d r y w e i g h t (W), l e a f a r e a ( L ) , l e a f (W ) , stem (W ) , r o o t (W ) w e i g h t s , l e a f w e i g h t r a t i o ( L W R ) , s p e c i f i c l e a f a r e a r a t i o (SLA) and l e a f a r e a r a t i o (LAR). R  A - without leaf residue; A-with leaf residue. R e g r e s s i o n l i n e s f o r W, L, W_ and W„ a r e h i g h l y s i g n i f i c a n t ; the r e s t are n o n - s i g n i r i c a n t .  61 o  g/pot  dm.  15  /pot  15  10  0l  L  OL  g/pot  g/pot 4r  5  OL g/pot  g/g/pot LWR  "A  0  OL  dm^/g/p-ot  3r-  dm  2  /g/pof 4 r  L AR  01-  OL  _L  30  52  75 DAYS  APTER  30  52  E M E R G E N C E  F i g u r e 16. The e f f e c t o f r o o t r e s i d u e on t h e t o t a l d r y w e i g h t (W), l e a f a r e a ( L ) , l e a f (WO, stem (W_), r o o t (W ) w e i g h t s , l e a f w e i g h t r a t i o (LWR), s p e c i f i c l e a f area r a t i o (SLA), and l e a f a r e a r a t i o (LAR). A -without root residue; • -with root residue. The above r e g r e s s i o n l i n e s a r e n o n - s i g n i f i c a n t .  75  62  of  leaf  again  residues.  The e x c e p t i o n  significantly  reduced.  Inspection o f Table several leaf on  significant  8 a l s o shows t h e r e  and r o o t r e s i d u e s , t h e m o s t s i g n i f i c a n t b e i n g  use  and q u a n t i t a t i v e v a l u e  Richards  (1941).  successive  representation  devised  I n such diagrams, the a b s c i s s a e increments  i n the l e v e l  or the i n t r o d u c t i o n o f a d d i t i o n a l f a c t o r s . represent  o f the  a n d r o o t r e s i d u e s more a p p a r e n t ,  h a s b e e n made o f t h e d i a g r a m a t i c  represent  t h e magnitude o f t h e e f f e c t  o f one f a c t o r The c o o r d i n a t e s  on t h e v a r i a b l e  question. For  for Richards' from  zero  example, i n t h i s diagrams  experiment the abscissae  f o r treatment  i n t e r a c t i o n s run  t o 2:  Level Level  Leaf  residue  0  1  Root  0  (Treat.  4)  (Treat.  1)  Residue  1  (Treat.  2)  (Treat.  3)  Treatment 4 corresponds and  those  r o o t w e i g h t and LWR.  i n t e r a c t i o n s between l e a f  in  were  i n t e r a c t i o n s between t h e e f f e c t s o f  To make t h e n a t u r e  by  i s r o o t weight which i s  treatment  3 to "2",  t o "CV , t r e a t m e n t s 1  (abscissae values).  1 a n d 2 t o "1"  63  Thus, a and may  b below are  two  possible  configurations  r e s u l t from a 2 x 2 f a c t o r i a l experiment:  In these examples, s o l i d l i n e s r e v e a l r e s i d u e s , and The  the  Where t h e r e are no  w i t h each f a c t o r a c t i n g parallelism indicates  between  form o f a p a r a l l e l o g r a m , The  absence o f  i n t e r a c t i o n between two  F i g . 17 shows the root i n t e r a c t i o n s  magnitude o f  interactions  independently.  the  indicated  the  i n the e f f e c t s of both types of  (Table 8), e.g.  W  p  and  L.  It will parallelism  that there  components o f growth, although not  significance  the  i n Table 8.  i n most of the diagrams which i n d i c a t e s  on  factors.  R i c h a r d s ' diagram f o r  be noted immediately t h a t t h e r e i s an absence of  interactions  leaf  residues.  form and  f a c t o r s , the diagram takes the  l e a f and  the e f f e c t s o f  broken l i n e s those o f r o o t  above diagrams i l l u s t r a t e  interactions. two  that  residues  a l l reach The  are  highly  statistical  64  dm  q/poi  0-9T  4  0-6  \  /g/pot 2r2  2  01  0-3 0»-  L  g/g/pof 0-5  g/pot 3T  LAR  _L  4— LWR J  OU  >  ^-3  L  d m /g/pot 2  )i-  4..  0 'S  0-L — L  F i g u r e 17. residue 1 - leaf 2 - root  Richard's ( f a c t o r ) diagram of root x l e a f i n t e r a c t i o n s . Means a c r o s s s a m p l i n g d a t e s . residue residue  3 - root leaf 4 - control  residue  LA  65  significant that  the  close on  i n t e r a c t i o n s on  presence of e i t h e r r e s i d u e  to maximal e f f e c t .  On  the  alone  other  LWR  show  results  hand, the  in a effects  t o t a l w e i g h t , t h e w e i g h t s o f l e a v e s , stems and  and  on  leaf  leaf  area  are  clearly  shown t o be  r a t h e r than root r e s i d u e s .  effect  of  leaf  r e s i d u e on W  illustrated  i n the  LWR  with  and  those  SLA  with  root  E,  R  and  The  t h a n on  caused  L  and  W  residue  are  slightly  greater  is  L  pods,  by  relatively  diagram i n which the v a l u e s  leaf  clearly for  LAR,  higher  from  curves  for  residue.  Figures R,  r o o t w e i g h t and  o  18  and  19  computed  present  fitted  from the p o l y n o m i a l s  derived  L f r o m t h e means o f W statistical both  and  comparisons  residue  sources  case of net  r e s i d u e s was  t h r o u g h o u t and the  of  o  can  be  area  trends  absence o f r o o t  .  effect  of  In leaf growth  r a t e s were  maintained  of plants  In g e n e r a l ,  that  relative  a  exceeded those  residues.  no  seen  throughout the  r o o t r e s i d u e s , the  eventually  be  i n the  g r o w t h r a t e and  a s s i m i l a t i o n r a t e s , the  with  Although  made, i t can  to cause a r e d u c t i o n  period, while  in  (Appendix 1 ) .  cause s i m i l a r  growth r a t e , r e l a t i v e the  L  the  grown values  show an  increase with  time, i n d i c a t i n g  maintenance of  the q u a d r a t i c  r e l a t i o n s h i p between W  and  the  of  However, i t i s a p p a r e n t t h a t R,  E  in  Experiment  the were  and  R^  at l e a s t  early stimulations  d e m o n s t r a t e d i n E x p e r i m e n t 3a were n o t 3b,  p o s s i b l y because o f  season o f the y e a r conducted.  a t which the  the  a L.  repeated  differences in  different  experiments  66  80 r  LEAF  80  RESIDUE  ROOT  R  v  RESIDUE  R  60h  60 v •  40  4 0 h  v  • v  20h  20  0*-  50r  50 A  v  v  T  25  v •-  V  25  0*-  30  52  oI  75 DAYS  AFTER  1-  30  52  • - with mg  . g  -1  residue; . day  -1  v - without ;  E:  mg  75  EMERGENCE  F i g u r e 18. The e f f e c t o f l e a f and r o o t r e s i d u e s on r e l a t i v e g r o w t h r a t e and n e t a s s i m i l a t i o n r a t e o f s e c o n d c r o p o f mungbeans.  R:  T  T V  . dm  residue. -2  . day  -1  the  67  6r L E A F  RESIDUE  ROOT  RESIDUE  v  •  v  T  •  V  ¥ _J_  01-'  o 1  8|  8 r  A  A A  o  X  _L 52  1  30  75 DAYS  30 A F T E R  52  E M E R G E N C E  F i g u r e 19. The e f f e c t o f l e a f and r o o t r e s i d u e s on t h e r e l a t i v e l e a f a r e a g r o w t h r a t e a n d R/R^ r a t i o o f t h e s e c o n d c r o p o f mungbean. • R : L  - with cm  2  residue;  .dm  -2  . day  v - without -1  ;  a  : R/Rj^  residue.  75  68  DISCUSSION  Residue  effects.  The e v i d e n c e i m p l i c a t i n g t h e  l e a v e s as t h e main s o u r c e o f p h y t o t o x i n c a u s i n g t h e r e s i d u e problem The  i n s e q u e n t i a l mungbean  cropping i s quiet  absolute values o f t o t a l dry weight  date o f p l a n t s growing (Experiment  and r o o t r e s i d u e s  50% o f t h e c o n t r o l  c a s e o f t h e one-week i n c u b a t i o n p e r i o d for  a t any s a m p l i n g  i n s o i l with leaf  3a) i s a b o u t  t h e 3-week i n c u b a t i o n .  clear.  values i n the  and a b o u t 40%  Where t h e e f f e c t  o f l e a f and  r o o t r e s i d u e s a r e s e p a r a t e d (Experiment  3b), t o t a l dry  weight  f o r p l a n t s grown  attained  respectively It  43% and 75% o f c o n t r o l s  i n s o i l with leaf-  and r o o t - r e s i d u e s .  has been o b s e r v e d i n f i e l d  s o i l w i t h mungbean r e s i d u e s w h i c h greatest effect  magnitude o f t h i s o b s e r v a t i o n may  effect  account  3-week i n c u b a t i o n  since  mungbean c r o p and  progressively  Such  f o r the greater e f f e c t  o f the  study the growing  was m a i n t a i n e d i n a m o i s t c o n d i t i o n Methods  reduces the  (Runeckles, 1975).  i n this  that  a r e k e p t m o i s t has t h e  on t h e s u b s e q u e n t  that drying of the s o i l  experiments  medium  ( s e e M a t e r i a l s and  section). The  g r e a t e r bulk o f the l e a f  dry matter  t h a t o f r o o t s , however, may n o t a c c o u n t a b s o l u t e magnitude o f the l e a f crop o f Experiment  over  f o r the g r e a t e r  residue effects.  3b h a d a 3:1 l e a f - r o o t w e i g h t  The  first  ratio  69  on  the average.  in  percent  root  Table  9 presents  the weight  o f c o n t r o l due t o l e a f ,  reduction  r o o t and l e a f  plus  residues.  T a b l e 9. Dry w e i g h t r e d u c t i o n o f mungbean a t f i n a l h a r v e s t , i n p e r c e n t o f c o n t r o l , c a u s e d by t h e i n c o r p o r a t i o n i n t h e s o i l o f l e a f , r o o t and r o o t p l u s l e a f r e s i d u e s o f p r e v i o u s mungbean c r o p .  Residues roots(R)  leaves(L)  L + R  Toxicity L/R  Variables percent Total  dry weight  53.7  13.8  52.6  3. 89  43.5 54.1 42.6 61.2  13.2 10.4 18.4 15.0  46.7 50.7 50.1 57. 5  3.29 5.2 2.3 4.1  Component w e i g h t s : leaves stem root pods  In t h i s  experiment, i t  will  were i n c u b a t e d f o r t w e l v e the on  leaf-root total  days .  that  I t w i l l be  closely  that  On a l a n d a r e a b a s i s u n d e r f i e l d  therefore,  there  from t h e p r e v i o u s  a r e more l e a f  residues  mungbean c r o p .  i s evenly  than  conditions, root  residues  However, a s s u m i n g  distributed  i s apparent t h a t the l e a f  t h a t o f the  (52.3%) i n E x p e r -  iment 3a.  it  noted  corroborates  c a u s e d by one-week i n c u b a t i o n  the p h y t o t o x i n  the residues  r e s i d u e mix c a u s e d a r e d u c t i o n o f 52.6%  dry weight which  reduction  be r e c a l l e d  i n the plant  that  tissues,  r e s i d u e w h i c h i s shown t o  70  cause about (Table  9)  4 t i m e s more r e d u c t i o n o f t o t a l  i s 12.3%  proportionate  (53.7  -  13.8  x  t o why  ( E x p e r i m e n t 2)  identity  and  caused  w e i g h t , 22.9%  very  leachates  and  nature  show p h y t o t o x i c i t y can  slightly  behave s i m i l a r l y  the  s u c h as  t o l e t t u c e and  to those  parts  immediate v i c i n i t y  in  the  soil.  i s known.  aglycones,  spinach  t h a t had  the  mostly nonpathogenic  and  extracted  decomposed u n d e r n a t u r a l  on  some p h y t o t o x i c i t y from  t o be  a t t r i b u t a b l e t o some breakdown p r o d u c t s  the  other  from the  h a n d , can  rhizosphere  ( E x p e r i m e n t 1) were n o t p h y t o t o x i c . to the  or  fragments  from l e s i o n s a t  (Experiment 3b),  similar  was  periods.  presence of  leachates  residues  contact with  roots  since  are  It is  seedlings  s u b s t a n c e s were p r e s u m e d t o have b e e n  The  plants  which  o f decomposing p l a n t  p o i n t o f i n j u r y were f o u n d t o be  for various  the  There  ( R i c e , 1974).  in direct  Organisms i s o l a t e d  from p l a n t r e s i d u e s  be  f i n d i n g s o f P a t r i c k e t a l . (1963)  the  tissues  only  t h e h a r m f u l e f f e c t s o f mungbean  in  conditions  leaves  u n d e r s t o o d once  phytotoxin  s o l u b l e i n water  t o the  that root injury  confined mainly  of  inhibitors,  also possible that  phytotoxic  of decomposing  I t c o u l d p o s s i b l y be  some p o t e n t  only  the  d i d not  surmised here.  in  residue  a  respectively. As  are  Leaf  pod  weight  ) more t o x i c on  residue weight b a s i s .  e v e n more r e d u c t i o n o f stem and 16.2%  3  dry  case o f A f r i c a n m a r i g o l d  be  the assumed  o f the of  intact  T h i s may  CTagetes  root  be erecta),  71  which  c o n t a i n s a c t i v e nematocides  which  has  failed  to y i e l d  from t h e e x u d a t e s 1964). that  The  the  roots  by m i c r o o r g a n i s m s  of the  but  compounds  (Clayton  c a n n o t be  t h e r o o t e x u d a t e s may  degraded  isolates  of i n t a c t  possibility  i n i t s roots,  and  Lamberton,  r u l e d o u t , however,  contain  compounds w h i c h when  produce  p h y t o t o x i n s and  e x p e r i m e n t a l c o n d i t i o n s were n o t f a v o r a b l e  that  for microbial  growth. S i n c e no b i o a s s a y was extracts, toxin and  i t i s not p o s s i b l e  to t e l l  i s p r e s e n t i n the l e a f  r e l e a s e d by  decay.  done on l e a f  There  i s always  (Patrick,  to  parameters  by s e a s o n o f p l a n t i n g . summer  (July  accumulation. of  t i s s u e s may  dry matter  i n peach  E x c e p t f o r R^,  of Experiment  those of Experiment  in  possibility be A  root  1955).  Growth p a r a m e t e r s . growth  the  formed  t o t o x i c ones by m i c r o b i a l m e t a b o l i s m .  good example i s t h e c a s e o f a m y g d a l i n residue  whether the phyto-  tissues or i s only  t h a t n o n - t o x i c compounds i n t h e p l a n t transformed  tissue  26,  3b.  3a show l i t t l e  P r o b a b l y , growth  Experiment  1978), had  Figure  the  similarity  was  influenced  3a, w h i c h was  the h i g h e s t  to season o f  planted  dry matter  20 p r e s e n t s t h e e x t e n t o f  a c c u m u l a t i o n due  derived  reduction  planting  2 (r  =0.769); t h e n e g a t i v e c o r r e l a t i o n  significant  a t t h e 5%  Experiments  3a and  level.  As  shown i n t h e  3b were grown d u r i n g  s e a s o n s where t h e maximum p o s s i b l e from  16  t o 13.5  (r= -0.877) i s  hours  and  from  10  light t o 8.2  two  figure,  distinct  duration hours  changed  respectively.  72  g/pot  r  40  ^y=36-(29345-0-l7874|f r=0-877*  |_  y=22  X  08-OI297938X r= 0 - 7 / 0 4  ns  A  0  -i—i—i— 14  _J  !_  80 OF  l.03 110 :  DAYS  Jul  Aug  Aug  Oct  26'78  9'78  23'77  l4'77  3a  I  3a  l_  JLI  28 NUMBER  Experiments  1  I  Nov 6'78 3b  Nov I3'77 2  F i g u r e 20. Reduction i n dry weight o f tops o f mungbean as i n f l u e n c e d by date of p l a n t i n g . Each o b s e r v a t i o n represents an average o f the c o n t r o l treatment. • : h a r v e s t e d a t m a t u r i t y (70-75 DAE) A : h a r v e s t e d a t r e p r o d u c t i v e stage (25-35 DAE)  73  L i g h t q u a l i t y and i n t e n s i t y under the g l a s s r o o f d u r i n g these two p e r i o d s would have been a l s o d i f f e r e n t , the l a t e r season b e i n g more cloudy. Poehlman (1978) r e p o r t e d l i t t l e success w i t h mungbean v a r i e t y f i e l d  t r i a l s grown above 40° l a t i t u d e ,  apparently due to the delay i n f l o w e r i n g r e s u l t i n g from long p h o t o p e r i o d o r poor growth due to the c o o l e r temperature.  Mean minimum temperature f o r p r o d u c t i v e  growth appears t o be between 20° and 2 2°C w i t h the optimum mean temperature i n the range of 2 8°-30°C. In both Experiments 3a and 3b, temperature was w i t h i n the above ranges  (see M a t e r i a l s and Methods)  and a p p a r e n t l y , f l o w e r i n g was s i n c e there was time.  not a f f e c t e d by l i g h t  duration  no observed change i n the d a y s - t o - f l o w e r i n g  T h i s o b s e r v a t i o n suggests that the d i f f e r e n c e i n  dry matter accumulation would have been due to the d i f f e r e n c e i n l i g h t i n t e n s i t y and s p e c t r a l This problem was  not a n t i c i p a t e d .  the Lucalox Sodium-vapor  I t was  distribution. thought t h a t  lamps, which d e l i v e r l i g h t i n  the p h o t o s y n t h e t i c a l l y a c t i v e r e g i o n o f the l i g h t  spectrum,  were adequate. Although the growth p a t t e r n i n Experiment 3b was  d i f f e r e n t from t h a t of Experiment 3a, the r e d u c t i o n  i n dry matter accumulation due to r e s i d u e , which i n Experiment 3b was  c l e a r l y shown to be due mainly to l e a f  residue, i s f a i t h f u l l y consistent.  The d e r i v e d  growth  parameters o f the c o n t r o l treatments i n Experiment 3a however agree Tsiung  (1978) .  very c l o s e l y to the ones r e p o r t e d by  74  There i s f u r t h e r s i m i l a r i t y 3a and  3b.  effects on  Figures  o f the  21  and  22 present  r e s i d u e treatments  the p a r t i t i o n i n g  of a s s i m i l a t e s over  It will  be  noted  r e s i d u e s s t i m u l a t e d the in  the  leaves  more p r o n o u n c e d as b r o u g h t up  assimilatory o f the E and plants  attained only  Figure  which  But  o f the  be  due  the  a b o u t 50% harvest.  i . e . , up  o f the  the  the  f o r the  dry  i s shown w i t h  delay  weight  leaf  root residues delay  i n pod  effects,  i n pod  gain over  Since  formation  not  observed  as d i s c u s s e d  E represents  respiratory loss  magnitude o f r e s p i r a t i o n  and  may  (Leopold  alone,  f o r m a t i o n may  observation  and  also earlier.  i n Experiment  a t the  the net  vary  allocation  residues  a p p a r e n t s t i m u l a t o r y e f f e c t o f r e s i d u e on  ( F i g . 12).  recovery  residue-grown  total  d e r i v e d growth parameter E p a r t i c u l a r l y stage  was  residue  same s t i m u l a t e d  a l s o shows t h e  most s t r i k i n g  to 2 8  increased  s i n c e the  The  leaves  This  of  apparent s t i m u l a t i o n of  ( F i g . 12)  i n p a r t to seasonal The  is  3a.  6  o f more a s s i m i l a t e s  among l e a f - r e s i d u e - t r e a t e d p l a n t s w h i c h was i n Experiment  These  This stimulation  to a l e s s e r degree with 22,  time.  incubation period of  R at that period  of a s s i m i l a t e s to the  in  Experiments  s u r f a c e , however, d i d l i t t l e  plant, inspite  and  accumulation  t o 3 weeks.  of c o n t r o l at f i n a l  alone,  comparative  t h a t the presence  ( F i g . 21).  the  Experiments  i n Appendices  a t the v e g e t a t i v e s t a g e ,  days a f t e r emergence  was  the  i n two  f i g u r e s summarize t h e d a t a p r e s e n t e d t h r o u g h 9.  between  3a  the  vegetative  photosynthetic  according  Kriedemann,  to  the  1975),  °/  /o  14  28 WITH  42 73 14 28 42 DAYS AFTER EMERGENCE  RESTDUE  WITHOUT  73  RESIDUE  F i g u r e 21. Component d r y w e i g h t s as p e r c e n t o f t o t a l d r y w e i g h t o f s u c c e e d i n g mungbean c r o p as a f f e c t e d by t h e r e s i d u e a n d l e n g t h o f i n c u b a t i o n o f p r e v i o u s mungbean c r o p .  /o  30  52  75  DAYS ROOT  ROOTS  AFTER  RESIDUE(R)  STEMS  30  52  EMERGENCE L + R  LEAVES  PODS  Figure 2 2 . Component d r y w e i g h t s as p e r c e n t o f t o t a l d r y w e i g h t o f s u c c e e d i n g mungbean c r o p as a f f e c t e d by t h e l e a f a n d / o r r o o t r e s i d u e s o f p r e v i o u s mungbean c r o p .  77  the apparent g r e a t e r magnitude o f the r a t e o f i n c r e a s e of R d u r i n g the v e g e t a t i v e stage r e l a t i v e t o the i n c r e a s e in assimilatory surface  ( F i g . 12) may account f o r the  g r e a t e r value f o r E over t h i s p e r i o d .  This w i l l  imply  t h a t there was l e s s r e s p i r a t o r y l o s s o f a s s i m i l a t e s d u r i n g the p e r i o d .  T h i s may suggest t h a t the p h y t o t o x i n  from the r e s i d u e acts as a r e s p i r a t o r y i n h i b i t o r t o growing s e e d l i n g s a f t e r i t has caused i n i t i a l during the germination  process.  damage  I t w i l l be r e c a l l e d  that there was more a s s i m i l a t e a l l o c a t e d t o the leaves among the residue-grown p l a n t s inhancing  ( F i g . 21), thus f u r t h e r  increased net photosynthesis,  grown without  over those  plants  residues.  This pattern of e f f e c t of stress i s s i m i l a r to  t h a t found of w a t e r - s t r e s s e d  19 55)  tomato p l a n t s  (Gates,  i n which, a f t e r w i l t i n g , lamina weight r a t i o s became  h i g h e r than those o f c o n t r o l s , stem weight r a t i o s became lower and E and R rose above c o n t r o l v a l u e s . The  present s t u d i e s are i n keeping with the  o b j e c t i v e s o f p i n p o i n t i n g the s p e c i f i c source o f p h y t o t o x i n from the p l a n t r e s i d u e o f previous  crop and d e s c r i b i n g  i t s e f f e c t on the growth parameters o f the succeeding crop.  The p r e s e n t s t u d i e s do not permit any e l a b o r a t i o n  o f the p l a n t s t a t u s e a r l i e r than 14 days a f t e r emergence. However, the i m p l i c a t i o n s o f the o v e r a l l r e s u l t s p o i n t out t h a t the e f f e c t s t a r t s r i g h t a t the germination The  s t a t u s o f the p l a n t a t the time o f sampling (or  observation)  r e f l e c t s the cummulative consequence o f  whatever the p l a n t was s u b j e c t e d t o e a r l i e r .  Hence,  process.  78  the observed d i f f e r e n c e s i n the growth parameters p l a n t s grown i n r e s i d u e - t r e a t e d s o i l  between  and those from r e s i d u e -  f r e e s o i l suggest the need to e l a b o r a t e the e f f e c t observed at the time o f emergence as i n d i c a t e d by the c o n d i t i o n s of  the s e e d l i n g s ( F i g s . 2 through 10) of the r e s i d u e -  treated  soil. O b v i o u s l y , i t would be i n t e r e s t i n g to determine  the e f f e c t of l e a f r e s i d u e on the germination p r o c e s s , and p a r t i c u l a r l y i t s e f f e c t on r e s p i r a t i o n .  Effects  on  e a r l y stage of growth, such as d u r i n g e l o n g a t i o n of the h y p o c o t y l and tap r o o t development, would a l s o be to know.  Information along these l i n e s would be  interesting useful  i n d e v e l o p i n g b i o a s s a y methods f o r i s o l a t e d compounds from l e a f t i s s u e e x t r a c t s .  Such i n f o r m a t i o n would a l s o  be u s e f u l i n d e v e l o p i n g s c r e e n i n g procedures t o survey the occurrence o f the p h y t o t o x i n among mungbean c u l t i v a r s .  79  SUMMARY  The purpose o f t h i s study was to i n v e s t i g a t e the e f f e c t s o f a mungbean crop on the growth  parameters  of a succeeding mungbean crop grown under v a r i o u s  conditions  o f p o t e n t i a l t r a n s f e r and source o f p h y t o t o x i c a n t s . The mungbean v a r i e t y , MG50-10a, used i n the experiments i s h i g h - y i e l d i n g and i s known t o have r e s i d u e problem i n a mungbean-mungbean s e q u e n t i a l c r o p p i n g . The r e s i d u e problem appeared not t o be a simple r e l e a s e o f p h y t o t o x i n from r o o t exudates o f i n t a c t p l a n t s o r o f decaying p l a n t m a t e r i a l s . complex.  1.  The e f f e c t i s more  The main r e s u l t s are summarized  below:  Root exudates leached from growing p l a n t s i n sand medium d i d not show p h y t o t o x i c i t y .  This  suggests t h a t r o o t exudate per se i s nonphytotoxic.  However, they may c o n t a i n compounds  which, through m i c r o b i a l metabolism, produce phytotoxins.  2.  The r e s i d u e e f f e c t was shown t o be dependent on p h y s i c a l c o n t a c t between subsequent crop r o o t s and r e s i d u e s .  Length o f decomposition, up t o  3 weeks, i n c r e a s e d p h y t o t o x i c i t y . t r a n s f e r r e d from decomposing d i d not show p h y t o t o x i c i t y .  Leachate  r e s i d u e s i n sand  Leaf r e s i d u e s were shown t o be more p h y t o t o x i c than r o o t r e s i d u e s .  Leaf p l u s r o o t r e s i d u e s were shown t o have no additive  effect.  Residue treatment prevented  normal s e e d l i n g  development and residue-grown p l a n t s a t t a i n e d about h a l f the t o t a l dry weight o f c o n t r o l s .  P l a n t s i n r e s i d u e - t r e a t e d s o i l have more a s s i m i l a t e a l l o c a t e d t o the leaves d u r i n g the v e g e t a t i v e stage, compared t o those residue-free s o i l .  During  from  t h i s stage E, R,  and LAR becomes c o n s i d e r a b l y g r e a t e r than f o r the c o n t r o l s .  Although R  L  i s i n c r e a s e d , which  may be due t o more a s s i m i l a t e s being a l l o c a t e d to  the l e a v e s , the g r e a t e r magnitude o f the  i n c r e a s e i n R over R  T  may account f o r the  i n c r e a s e i n the value o f E.  T h i s would be  p o s s i b l e i f there i s a r e d u c t i o n i n r e s p i r a t o r y l o s s e s , which suggests t h a t the r e s i d u e s may be r e l e a s i n g a r e s p i r a t o r y i n h i b i t o r .  REFERENCES  Anderson, R.C. and O.L. Loucks. 1966. Osmotic pressure i n f l u e n c e i n germination t e s t f o r a n t i b i o s i s . S c i e n c e 152:771-772. B e l l , D.T. and D.E. Koeppe. 1972. Noncompetitive e f f e c t s of g i a n t f o x t a i l on the growth o f corn. Agronomy J . 64:321-324. Borner, H. 1960. L i b e r a t i o n o f o r g a n i c substances from h i g h e r p l a n t s and t h e i r r o l e i n the s o i l s i c k n e s s problem. Bot. Rev. 26: 393-424. B u t t e r y , B.R. 1969. A n a l y s i s of growth o f soybeans as a f f e c t e d by p l a n t p o p u l a t i o n and f e r t i l i z e r . Can. J . P l a n t S c i . 49: 684-685. Chou, Chang-Hung and Z.A. P a t r i c k . 1976. I d e n t i f i c a t i o n and p h y t o t o x i c a c t i v i t y o f compounds produced d u r i n g decomposition o f corn and rye r e s i d u e s in s o i l . J . Chem. E c o l . 2: 369-387. Chou, Chang-Hung and Hui-Jung L i n . 1976. A u t o i n t o x i c a t i o n mechanism o f Oryze sativa. I. Phytotoxic e f f e c t s of decomposing r i c e r e s i d u e s i n s o i l . J . Chem. E c o l . 2: 353-367. Chou, C H . and C.C. Young. 1974. E f f e c t s o f osmotic c o n c e n t r a t i o n and pH on p l a n t growth. Taiwania 19_: 157-165. C l a y t o n , M.F. and J.A. Lamberton. 1964. Study o f r o o t exudates by the fog-box technique. A u s t r a l i a n J . B i o l . S c i . 17: 855-859. Cochran, V.L., L.F. E l l i o t t and R.I. Papendick. 1977. The p r o d u c t i o n of phytotoxins from s u r f a c e crop r e s i d u e s . S o i l S c i . Soc. Am. J . 4JL: 903-908. D e v e r a l l , B.J. 19 72. P h y t o a l e x i n s . In Phytochemical Ecology. J.B. Harborne (ed.) pp. 217-233. London: Academic P r e s s , pp. 272. Evans, G.C. 1972. The q u a n t i t a t i v e a n a l y s i s o f p l a n t growth. In S t u d i e s i n Ecology, V o l . 1, Univ. o f C a l i f . Press and B l a c k w e l l S c i . P u b l . pp. 734. Fay, P.K. and W.B. Duke. 1977. An assessment o f a l l e l o p a t h i c p o t e n t i a l i n Avena germplasm. Weed S c i . 25: 224-228.  82  F r i e d m a n n , O.T. and M. H o r o w i t z . 1971. B i o l o g i c a l l y a c t i v e substances i n subterranean parts o f purple nutsedge. Weed S c i . 19: 398-401. Gates,  C.T. 1955. The r e s p o n s e o f t h e young tomato p l a n t to a b r i e f p e r i o d o f water shortage. I . The w h o l e p l a n t and i t s p r i n c i p a l p a r t s . Aust. J . B i o l . S c i . 8: 196-214.  G u e n z i , W.D. a n d T.M. M c C a l l a . 1966. P h y t o t o x i c s u b s t a n c e s e x t r a c t e d from s o i l . S o i l S c i . S o c . Am. P r o c . 30: 214-216. Harborne,  J . B . 1972. P h y t o c h e m i c a l A c a d e m i c P r e s s , pp. 272.  Ecology.  London:  H u n t , R. a n d I . T . P a r s o n s . 19 74. A computer p r o g r a m f o r d e r i v i n g g r o w t h - f u n c t i o n s i n p l a n t growth a n a l y s i s . J . A p p l . E c o l . 11: 297-307. H u n t , R. and I . T . P a r s o n s . 1977. P l a n t g r o w t h a n a l y s i s : Further applications of a recent c u r v e - f i t t i n g p r o g r a m . J . A p p l . E c o l . 14^: 965-968. I n t e r n a t i o n a l R i c e Research I n s t i t u t e (IRRI), Annual R e p o r t f o r 1973, L o s B a n o s , P h i l i p p i n e s , 1974. pp. 16-34. J a c k s o n , J.R. a n d R.W. W i l l e m s e n . 1976. A l l e l o p a t h y i n t h e f i r s t s t a g e s o f s e c o n d a r y s u c c e s s i o n on t h e P i e d m o n t o f New J e r s e y . Am. J . B o t . 6_3: 1015-1023. R o l l e r , H.R., W.E. N y q u i s t a n d I . S . C h o r u s h . 1970. Growth a n a l y s i s o f t h e s o y b e a n community. C r o p S c i . 1 0 : 407-412. Kommedahl, T. a n d J.H. Ohman. 1960. The r o l e o f Agropyron repens i n the s e e d l i n g b l i g h t epedemiology o f a l f a l f a and c e r e a l s . P r o c . Minn. Acad. S c i . 23: 10-15. Last,  F.T. 1962. A n a l y s i s o f t h e e f f e c t s o f graminis D.C. on t h e g r o w t h o f b a r l e y . B o t . n . s . 2_6: 279-289.  Erysiphe Ann.  L e o p o l d , A.C. a n d P.E. K r i e d e m a n n . 1975. P l a n t Growth and D e v e l o p m e n t . M c G r a w - H i l l , N.Y. 554 p p . L o d h i , M.A.K. 1976. R o l e o f a l l e l o p a t h y as e x p r e s s e d by dominating trees i n a lowland f o r e s t i n c o n t r o l l i n g t h e p r o d u c t i v i t y and p a t t e r n o f h e r b a c e o u s growth. Am. J . B o t . 63: 1-8.  83  M c C a l l a , T.M. Adv.  and T.S. Army. 1961. Agron. 13= 125-196.  Stubble-mulch  farming.  M u l l e r , C.H., R.B. H a n a w a l t , J.K. M c P h e r s o n . 1968. A l l e l o p a t h i c c o n t r o l o f herb growth i n the f i r e cycle of C a l i f o r n i a chaparral. B u l l . TorreyJBot. 95: 225-231.  Club  N i e l s e n , K.F., T.F. Cuddy, andW.B. Woods. 1960. The i n f l u e n c e o f t h e e x t r a c t o f some c r o p s and s o i l r e s i d u e s on g e r m i n a t i o n and g r o w t h . Can. J . P l a n t S c i . 40_£ 188-197. N o r s t a d t , F.A. and T.M. M c C a l l a . 1968. Microbial population i n stubble-mulch s o i l . Soil Sci. 10 7: 188-193. Norstadt,  F.A. and T.M. M c C a l l a . 1963. Phytotoxic s u b s t a n c e s from s p e c i e s o f Penicilium. Science 140: 410-411.  Patrick,  Z.A. 1955. Peach r e p l a n t problem i n O n t a r i o . II. T o x i c s u b s t a n c e s from m i c r o b i a l d e c o m p o s i t i o n p r o d u c t s o f p e a c h r o o t r e s i d u e s . Can. J . B o t . 3_3: 461-486.  Patrick,  Z.A. and L.W. Kock. 1958. Inhibition of r e s p i r a t i o n , g e r m i n a t i o n and g r o w t h by s u b s t a n c e s a r i s i n g during decomposition of c e r t a i n p l a n t residues i n the s o i l . Can. J . B o t . 36_: 621-647.  Patrick,  Z.A., T.A. T o u s s o u n and W.C. Snyder. 1963. Phytotoxic substances i n arable s o i l a s s o c i a t e d with decomposition of p l a n t r e s i d u e s . Phytopathology 53: 152-161.  P o e h l m a n , J.M. 1978. What we have l e a r n e d I n t e r n a t i o n a l Mungbean N u r s e r i e s . I n t e r n a t i o n a l Mungbean Symposium. the O f f i c e of I n f o r m a t i o n S e r v i c e s V e g e t a b l e R e s e a r c h and Development Taiwan, ROC.  from t h e I n The f i r s t P u b l i s h e d by a t the A s i a n C e n t r e , Shanhua,  Putnam, A.R. and W.B. Duke. 1974. Biological supression o f weeds: E v i d e n c e f o r a l l e l o p a t h y i n a c c e s s i o n s of cucumbers. S c i e n c e 185: 370-372. Putnam, A.R. and W.B. Duke. 1978. Allelopathy in agroeco-systerns. Ann. Rev. P h y t o p a t h o l . 16: 431-451.  84  Q u i n n , J . A . 1974. Convolvulus sepium in old field s u c c e s s i o n on t h e New J e r s e y P i e d m o n t . Bull. T o r r e y B o t . C l u b . 101: 89-95. Radford,  P . J . 1967. Growth a n a l y s i s f o r m u l a e u s e and a b u s e . C r o p S c i . 7_ 171-175.  their  :  Rice, E.L.  1974.  Allelopathy.  Academic P r e s s ,  N.Y.  R i c e , E . L . 1972. A l l e l o p a t h i c e f f e c t s o f Adropogon virginicus and i t s p e r s i s t e n c e i n o l d f i e l d s . Am. J . B o t . 59: 752-755. R i c h a r d s , F . J . 1941. The d i a g r a m a t i c r e p r e s e n t a t i o n o f t h e r e s u l t s o f p h y s i o l o g i c a l and o t h e r e x p e r i m e n t designed f a c t o r i a l l y . Ann. B o t a n y , n . s . 5_: 250-261. Richards, F.J. 1969. The q u a n t i t a t i v e a n a l y s i s o f g r o w t h . pp. 3-76. I n P l a n t P h y s i o l o g y , A T r e a t i s e , F.C. S t e w a r d (edTT, A c a d e m i c P r e s s , N.Y. R u n e c k l e s , V.C. 1974. An e v a l u a t i o n o f t h e b i o c h e m i c a l p r o j e c t on p l a n t i n t e r a c t i o n s i n m u l t i p l e c r o p p i n g systems. Report t o t h e I n t e r n a t i o n a l Development Research Centre. Dept. o f P l a n t S c i e n c e , U.B.C, V a n c o u v e r , Canada, /mimeo/ R u n e c k l e s , V.C. 1975. R e s e a r c h i n t o t h e mechanisms o f crop r e s i d u e e f f e c t s i n m u l t i p l e cropping systems: A r e v i e w o f p r o g r e s s and p r o p o s a l s f o r f u t u r e research. Report to the I n t e r n a t i o n a l Research C e n t r e , Ottawa, Canada. Dept. o f P l a n t S c i e n c e , U . B . C , V a n c o u v e r , Canada, /mimeo./ Sadhu, M.K. and T.M. D a s . 1971. R o o t e x u d a t e s o f r i c e seedlings. The i n f l u e n c e o f one v a r i e t y on another. P l a n t S o i l 34_ 541-546. :  S a n c h e z , P.A. 1976. P r o p e r t i e s a n d Management o f S o i l i n t h e T r o p i c s . W i l e y - I n t e r s c i e n c e P u b l . , N.Y. pp. 478-482. Sestak,  Z., J . C a t s k y , and P.G. J a r v i s ( e d s . ) . 1971. P l a n t P h o t o s y n t h e t i c P r o d u c t i o n , Mannual o f M e t h o d s . W. J u n k , P u b l i s h e r s , The Hague, pp. 818.  S i k u r a j a p a t h y , M. 1974. The e f f e c t o f t h e p r e v i o u s c r o p on t h e p e r f o r m a n c e o f s u c c e e d i n g c r o p s . Master's t h e s i s , Univ. o f the P h i l i p p i n e s , Los Banos, Philippines.  85  Swain, T. 19 77. Secondary compounds as p r o t e c t i v e Ann. Rev. P l a n t P h y s i o l . 2_8: 479-501.  agents  Thome, G.N. 1960 . V a r i a t i o n w i t h age i n NAR and o t h e r growth a t t r i b u t e s o f sugar-beet, p o t a t o and b a r l e y i n c o n t r o l l e d environment. Ann. Bot., n.s., 2_4_: 356-371. Toussoun, T.A. , A.R. Weinhold, R.G. Linderman, and Z.A. Patrick. 196 8. Nature o f p h y t o t o x i c substances produced d u r i n g p l a n t r e s i d u e decomposition i n soil. Phytopathology 5_8: 41-45. T s i u n g , N.T. 1978. i n Sarawak. Symposium. Services at Development  Response o f Mungbean to sowing date In The F i r s t I n t e r n a t i o n a l Mungbean P u b l i s h e d by the O f f i c e o f Information the A s i a n Vegetable Research and Centre, Shanhua, Taiwan, R.O.C.  Ventura, W. and I . Watanabe. 197 8. Growth i n h i b i t i o n due t o continuous cropping o f d r y l a n d r i c e and other c r o p s . S o i l S c i . P l a n t Nutr. 2_4: 375-389. Wang, T.S.C., T.K. Yang and T.T. Chuang. 1967. S o i l p h e n o l i c a c i d s as p l a n t growth i n h i b i t o r . Soil Sci. 103: 239-246. Whitehead, D.C. 1963. Some aspects o f the i n f l u e n c e o f o r g a n i c matter on s o i l f e r t i l i t y . S o i l and F e r t i l i z e r s 26_: 217-223. Whitehead, D.C. 1964. I d e n t i f i c a t i o n o f p-;hydroxy ben z o i c , v a n i l l i c , p-coumaric, and f e r u l i c a c i d s i n s o i l . Nature (London) 202: 417-418. W h i t t a k e r , R.H. 1970. The b i o c h e m i c a l e c o l o g y o f h i g h e r plants. In_ C h e m i c a l E c o l o g y , E . S o n d h e i m e r and J . B . Simeone (eds.) p p . 43-70. A c a d e m i c P r e s s , N.Y. Wilson,  R.E., E . L . R i c e . 1968. A l l e l o p a t h y as e x p r e s s e d by Helianthus annuus and i t s r o l e i n o l d f i e l d succession. B u l l . T o r r e y B o t . C l u b . 95:432-438.  Wood, R.K.S. and A. G r a n i t e . 1976. S p e c i f i c i t y Diseases. Plenum P r e s s , N.Y. p p . 354.  i n Plant  APPENDIX  P o l y n o m i a l e q u a t i o n s f i t t e d t o dry w e i g h t s and l e a f areas and Tables o f means o f f i t t e d and a c t u a l d a t a and o t h e r growth parameters  o f Experiments 3a and  3b.  87  APPENDIX 1  Polynomial equations f i t t e d to the mean t o t a l dry weight and  (L)  l e a f area  (W)  data on sampling time ( t ) .  Experiment 3a. Treat. 1  Treat. 2  39941  L  16887 + .14576t + ,007351t  W  21569 + .020066t + .020216t  2  - .0007209t  50749 + •83727t - .0036837t  2  - .000014149t  L Treat. 3  =  W  — •  L Treat. 4  -  W  W  62291 26105  *™  •  .18684t + .016089t  4742 -•  .27338t + .015732t  -  2  - .00013422t  2  -  .041463t + .0058086t •  389t + .039174t  2  .000080782t  - .00013699t  2  3  3  3  3  - .00018043t  2  3  - ,000043845t 3  2  - .00037363t  L =—te« 19406 + .27297t + .015845t  3  3  Experiment 3b.  Treat. 1  Treat. 2  Treat. 3  Treat. 4  W  .001 + .0012317t + .0012827t  L  .001 + .043475t + .0018639t  W  .001 + .018902 + ,0012173t  L  .001 + .10865t + .00085193t  W  .001 - .00087638t + ,0015323t  L  .001 + .088115t + .00023259t  W  .001 + .063168t + .0063179t  L  .001 + .10983t + .0024819t  +  .000010828t -  2  2  .00000097851t  - .000017437t  2  2  2  -  2  2  3  3  .0000085666t -  2  -  3  .000003547t  3  .0000051767t  3  - .000037707t - .000027688t  3  3  3  88  APPENDIX 2  A c t u a l and f i t t e d data on the changes on mean t o t a l dry weights  (W) i n Experiment 3a.  Treatments  -  Days After Emergence  Fitted Actual (g/pot o f 4 p l a n t s )  1) One week Incubation  14 28 42 73  1.012 4.254 11.270 20.260  0.569 4.835 10.989 20.284  2) C o n t r o l f o r Treat. 1  14 28 42 73  3.748 13.162 27.818 42.478  3.987 12.849 23.970 42.466  3) Three weeks Incubation  14 28 42 73  0.776 0.626 7.550 11.140  -0.497 2.295 6.743 11.211  4) C o n t r o l f o r Treat. 3  14 28 42 73  2.402 11.148 26.016 35.452  1.681 12.093 25.558 35.487  89  APPENDIX 3  A c t u a l and f i t t e d data on the changes on mean l e a f areas (L) i n Experiment 3a.  Treatments  Days After Emergence  Actual Fitted (g/pot of 4 p l a n t s )  1) One week Incubation  14 28 42 73  2. 498 8.698 12.562 18.260  3.099 7.910 12.943 18.227  2) C o n t r o l f o r Treat. 1  14 28 42 73  8.566 22.212 25.914 35.580  10.453 19.737 27.111 35.478  3) Three weeks Incubation  14 28 42 73  1.664 1.426 6.130 11.080  0.699 2.692 5. 518 11.132  4) C o n t r o l f o r Treat. 3  14 28 42 73  5.514 16.860 25.394 34.018  6.238 15.911 25.854 33.980  APPENDIX 4 Means o f t o t a l d r y w e i g h t , l e a f  a r e a , d r y w e i g h t s o f l e a v e s , s t e m s , r o o t s and p o d s . 2  (Weights a r e e x p r e s s e d i n g/pot o f 4 p l a n t s Experiment  3a.  Variables  and l e a f  a r e a i n dm  /pot of 4 plants).  Days A f t e r Emergence 28 42  14  73  1..01  3,.75  1 week i n c u b a t i o n / c o n t r o l 4,.25 13 .16 23. 82 11. 27  20. 26  42. 48  area  2..50  2,.57  8..70  22 .21  12. 56  25. 91  18. 26  35. 58  Leaf dry weight  0..60  1..99  2..27  6 .76  4. 29  8. 52  6. 98  12. 86  Stem d r y w e i g h t  0..27  1..12  1..50  4 .71  3. 10  6. 40  3. 82  8. 08  Root d r y w e i g h t  0..14  0.,64  0..48  1 .69  0. 98  2. 28  2. 10  3. 86  -  2. 90  6. 62  7. 36  17. 68  Total Leaf  Pod  dry weight  dry weight  3 weeks i n c u b a t i o n / c o n t r o l T o t a l dry weight  0.,78  2.,40  0..63  11 .15  7. 55  26. 02  11. 14  35. 45  Leaf  area  1..66  5.,51  1..43  16 .86  6. 13  25. 39  11. 08  34. 02  Leaf dry weight  0.,41  1.,27  0.,40  5 .56  2. 14  8. 08  3. 70  11. 84  Stem d r y w e i g h t  0..26  0.,72  0..13  4 .20  1. 78  7. 36  2. 10  9. 10  Root d r y w e i g h t  0.,12  0.,41  0.,09  1 .39  0. 49  2. 20  1. 12  3. 55  3. 14  8. 38  4. 22  10. 96  Pod  dry weight  —  91  APPENDIX 5 Means o f t o t a l dry weights, l e a f a r e a , dry weights o f l e a v e s , r o o t s , and pods.  (Weights are expressed i n  g/pot o f 4 p l a n t s and l e a f area i n dm /pot o f 4 p l a n t s ) . Experiment 3b.  Treatments Variables  Leaves  Roots  Root & Leaves  Contn  30 DAE T o t a l dry weight  1.166  1.956  1.258  2.774  Leaf area  2.212  3.797  2.713  4.781  Leaf weight  .688  1.0 86  .708  1.378  Stem weight  .380  .710  .460  .888  Root weight  .098  .160  .090  .508  52 DAE T o t a l dry weight  3.396  5.798  3.600  8. 498  Leaf area  4. 850  6. 751  4.563  8.532  Leaf weight  2.004  2. 878  2.038  3.520  Stem weight  1.118  1. 888  1.314  2.270  Root weight  .274  .412  .248  1.282  Pod weight  -  -  .620  1.426  75 DAE T o t a l dry weight  6.896  12.834  7.058  14.894  Leaf area  6.390  9. 327  5.732  10.518  Leaf weight  2. 202  3. 384  2.078  3.900  Stem weight  1. 596  3.118  1.714  3.480  Root weight  .566  .804  .492  .986  2.532  5.548  2.744  6.528  Pod weight  92  APPENDIX 6 Root/Weight Experiment  Ratios 3a  Days Treatment  1) 1 week 2) C o n t r o l 3) 3 week 4) C o n t r o l  incubation (1) incubation (3)  Experiment  A f t e r Emergence  14  28  42  73  .14  .11  .09  .10  .17  .13  .10  .09  .15  .14  .06  .10  .17  .12  .08  .10  3b  Days A f t e r Emerge nee Treatment  30  52  75  Leaf residue  (L)  .08  .08  .08  Root  (R)  .08  .07  .06  R & L  .07  .07  .07  Control  .18  .15  .07  residue  93  APPENDIX 7 Stem/Weight Experiment  Ratios 3a  Days A f t e r Emergence Treatment  14  28  42  73  .27  .35  .28  .19  2) C o n t r o l (1)  .30  .36  .27  .19  3) 3 week  .33  .21  .24  .19  .30  .38  .28  .26  1) 1 week  incubation  incubation  4) C o n t r o l (3)  Experiment  3b  Days A f t e r Emergence Treatment  30  52  75  Leaf residue  (L)  .33  .33  .23  Root r e s i d u e  (R)  .36  .33  .24  R & L  .37  .37  .24  Control  .32  .27  .23  94  APPENDIX 8  Leaf/Weight Ratio  (W  /W)  E x p e r i m e n t 3a  Days A f t e r Emergence 14  28  42  73  .59  .53  .34  .34  2) C o n t r o l (1)  .53  .51  .36  .30  3) 3 week  .52  .63  .28  . 33  .53  .50  .31  .33  Treatment  1) 1 week  4) C o n t r o l  incubation  incubation (2)  E x p e r i m e n t 3b  Days A f t e r Treatment  Leaf  Emergence  30  52  75  residue  (L)  .59  .59  .32  Root r e s i d u e  (R)  .55  .50  .26  R & L  .56  .57  .29  Control  .50  .41  .26  95 APPENDIX 9  a) Pod/whole p l a n t w e i g h t  Experiment  ratio.  3a  Days A f t e r Emergence Treatment  42  73  1) 1 week i n c u b a t i o n  .26  .36  2) C o n t r o l  .28  .42  3) 3 weeks i n c u b a t i o n  .42  .38  4) C o n t r o l  .32  .31  (1)  (3)  b) Pod/whole p l a n t w e i g h t  Experiment  ratio  3b  Days A f t e r Emergence Treatments  52  75  0  .37  .11  .43  R & L  0  .39  Control  .17  .44  Leaf  residue  Root r e s i d u e  (L) (R)  

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