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UBC Theses and Dissertations

Studies on the morphology and chemical composition of the roots of several annual and perennial grasses Pongskool, Virote 1962

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STUDIES ON THE MORPHOLOGY AND CHEMICAL COMPOSITION OF THE ROOTS OF SEVERAL ANNUAL AND PERENNIAL GRASSES by VIROTE PONGSKOOL B. S. A., K a s e t s a r t U n i v e r s i t y , Bangkok, T h a i l a n d , 1957.  A THESIS SUBMITTED IN PARTIAL FULFILMENT OF THE REQUIREMENTS FOR THE DEGREE OF MASTER OF SCIENCE I N AGRICULTURE  i n t h e Department of Plant  Science  We a c c e p t t h i s t h e s i s as conforming t o t h e required standard  THE UNIVERSITY OF BRITISH COLUMBIA March, 1962  In presenting  t h i s thesis i n p a r t i a l f u l f i l m e n t of  the requirements for an advanced degree at the University of B r i t i s h Columbia, I agree that the Library s h a l l make i t f r e e l y available f o r reference and study.  I further agree that permission  f o r extensive copying of t h i s t h e s i s f o r scholarly purposes may granted by the Head of my Department or by his  be  representatives.  It i s understood that copying or publication of t h i s thesis f o r f i n a n c i a l gain s h a l l not be allowed without my written permission.  Department of The University of B r i t i s h Columbia, Vancouver 8 , Canada.  ABSTRACT  Root and top development of an annual g r a s s , b a r l e y (Hordeum s a t i v u m ) , and of t h r e e v a r i e t i e s of p e r e n n i a l grass, orchard grass  ( D a c t y l i s glomerata) i s f o l l o w e d  d u r i n g the f i r s t year from s e e d i n g .  Reserve  carbohydrate  and l i g n i n l e v e l s f o r b o t h r o o t and top a t s e v e r a l dates are g i v e n .  A t t e n t i o n i s a l s o d i r e c t e d towards the  development of t e c h n i q u e s  f o r r o o t s t u d y , and t o r o o t  i n t e r a c t i o n s of g r a s s and legume s e e d l i n g s i n pure mixed  stands.  and  ACKNOWLEDGMENTS I w i s h t o take t h i s opportunity ness t o those who i n t r o d u c e d  t o e x p r e s s my  indebted-  me t o Canada and who guided me i n  my p e r i o d o f s t u d y . I would l i k e t o extend s p e c i a l thanks t o Dr. Vernon C. Brink, Professor Plant Science,  of Agronomy and Chairman o f t h e D i v i s i o n o f  U n i v e r s i t y of B r i t i s h Columbia, under whose  s u p e r v i s i o n t h i s p r o j e c t was u n d e r t a k e n .  I s h a l l always be  i n d e b t e d t o him not o n l y f o r h i s d i r e c t i o n and a s s i s t a n c e i n c o n d u c t i n g and p r e p a r i n g  t h i s t h e s i s , but a l s o f o r h i s  and warm u n d e r s t a n d i n g w h i c h c o n t r i b u t e d and p l e a s a n t operation,  p e r i o d o f study.  greatly to a useful  I a l s o thank f o r t h e i r co-  Mr. Don P e a r c e , s e n i o r t e c h n i c i a n , Mr. J a n B r u s s e l ,  former l a b o r a t o r y t e c h n i c i a n i n t h e D i v i s i o n o f P l a n t and  patience  Science,  Mrs. Agnes B e l l , M i s s Lyn J o l l y , and Mrs. Suzanne L o r e n c z i ,  Secretaries. I would l i k e t o e x p r e s s my deepest p e r s o n a l  gratitude  t o Mr. R o d e r i c k C. B a i l e y , of t h e 4-H Club B r a n c h , t h e Department of A g r i c u l t u r e , B r i t i s h Columbia, and my former colleague  a t t h e Thailand-UNESCO Fundamental E d u c a t i o n C e n t r e ,  Ubon, T h a i l a n d ,  and t o h i s f a m i l y whose r e a l i n t e r e s t made i t  p o s s i b l e f o r me t o come t o study i n Canada under t h e E x t e r n a l A i d Programme (Colombo P l a n ) .  G r a t i t u d e i s a l s o e x p r e s s e d t o my Government f o r g r a n t i n g me l e a v e of absence.  G r a t e f u l acknowledgment i s  a l s o made t o the Government of Canada f o r the f i n a n c i a l a i d .  TABLE OF CONTENTS  INTRODUCTION  1  REVIEW OP LITERATURE  2  Root  2  Study Techniques  Seasonal of  r o o t d e v e l o p m e n t and l e n g t h o f  life 4  roots  Root  interaction  Chemical  of crops  composition  growing i n a s s o c i a t i o n  7 8  of roots  EXPERIMENTATION Project  1 - Direct  observation  in soil  of growing  roots Project  Project  2 - Direct observation of p o s s i b l e i n t e r a c t i o n s o f g r a s s and legume r o o t s in s i t u 3 - The d e v e l o p m e n t o f a r o o t w a s h i n g machine  Project  Project  4 - C o m p a r a t i v e r o o t d e v e l o p m e n t o f an a n n u a l g r a s s ( b a r l e y Hordeum s a t i v u m ) and a p e r e n n i a l g r a s s ( o r c h a r d g r a s s D a c t y l i s glomerata ) from seed 5 - Time o f o n s e t in  Project  Project  of s e e d l i n g  grass  16 20  24  competition  stands  33  6 - S e a s o n a l t r e n d s I n l i g n i n and r e s e r v e c a r b o h y d r a t e i n t h e r o o t s and t o p s o f barley  4l  7 - S e a s o n a l t r e n d s i n l i g n i n and r e s e r v e c a r b o h y d r a t e i n t h e r o o t s and t o p s o f a f i r s t year stands of three orchard grass v a r i e t i e s  4-9  GENERAL DISCUSSION  AND  SUMMARY  59 63  APPENDIX LITERATURE  forage  12  CITED  69  STUDIES ON THE MORPHOLOGY AND CHEMICAL  COMPOSITION  OP THE ROOTS OP SEVERAL ANNUAL AND PERENNIAL GRASSES  INTRODUCTION  Much i s known about t h e a e r i a l p a r t s o f c r o p s , and t h e i r morphology and p h y s i o l o g y has been the s u b j e c t of innumerable s t u d i e s . crops a r e few.  By c o n t r a s t the s t u d i e s of the r o o t s of  The r e a s o n f o r the p a u c i t y of work on r o o t s  appears t o stem l a r g e l y from t h e l a b o u r i o u s n e s s r o o t study t e c h n i q u e s are o b t a i n e d  of current  and from t h e f a c t t h a t i n t a c t r o o t systems  o n l y under v e r y s p e c i a l and a t y p i c a l c o n d i t i o n s .  I t i s a p p a r e n t , however, t h a t a g r e a t e r knowledge o f the whole p l a n t , tops and r o o t , would be h i g h l y d e s i r a b l e i n t h e s o l u t i o n of many k i n d s o f problems i n crop p r o d u c t i o n g e n e r a l l y and, more s p e c i f i c a l l y , i n f o r a g e and t u r f p r o d u c t i o n . on r o o t - t o p i n t e r a c t i o n s , on r o o t d e c o m p o s i t i o n age,  on r o o t c h e m i s t r y ,  Good s t u d i e s  i n s o i l with  on r o o t c o m p e t i t i o n and even on r o o t  morphology a r e c o m p a r a t i v e l y few. In t h i s study, work on r o o t s i n i t i a t e d by a former s t u d e n t , Mr. Rex F r e d e r i c k ( 1 9 5 9 ) , and development of t e c h n i q u e s and a b e g i n n i n g  i s continued.  Examination  f o r r o o t study a r e c o n t i n u e d  i s made i n t h e study o f r o o t c h e m i s t r y and  root/top interactions.  A d d i t i o n a l l y , a comparison i s made  of r o o t development i n an a n n u a l and p e r e n n i a l g r a s s .  2 REVIEW OF LITERATURE The  l i t e r a t u r e on the r o o t s o f g r a s s e s has been the  s u b j e c t o f a r e c e n t , e x c e l l e n t r e v i e w by Troughton (1957), of the Welsh P l a n t B r e e d i n g  S t a t i o n , A b e r y s t w y t h , Wales.  Inasmuch as t h i s covers much o f the l i t e r a t u r e r e l a t i v e t o the f i e l d , l a b o r a t o r y , and greenhouse s t u d i e s l a t e r  described,  the l i t e r a t u r e surveyed i n t h i s t h e s i s i s l i m i t e d .  No t r u l y  comprehensive r e v i e w physiology been made.  on the e v o l u t i o n , morphology and  o f r o o t s f o r the p l a n t kingdom appears t o have A p i c t o r i a l p r e s e n t a t i o n o f r o o t morphology I n  h i g h e r crop p l a n t s was developed by Weaver (1926), a f t e r painstaking excavation  s t u d i e s ; these s t u d i e s were extended  by Canadian, German and R u s s i a n workers (e.g. P a v l y c h e n k o , 1937,  1942).  Evans (1958) has s t u d i e d , i n c o n s i d e r a b l e  d e t a i l , the development o f the t i m o t h y r o o t system and Cormack (194-9) has r e v i e w e d knowledge o f the r o o t h a i r and i s c u r r e n t l y engaged i n a more u p - t o - d a t e p r e s e n t a t i o n .  Root study  techniques  S i n c e t h i s study grew out o f an e a r l i e r study by F r e d e r i c k (1959) and, techniques  inasmuch as he r e v i e w e d i n some d e t a i l  used i n r o o t study t o 1959, t h e r e i s l i t t l e  i n repeating h i s review.  The most s i g n i f i c a n t  point  addition to  r o o t study d u r i n g the l a s t t h r e e y e a r s appears t o be t h a t  3  of B u r t o n (1962) who has used an " e x h a u s t i o n  of root  r e s e r v e s " i n darkness o r " e t i o l a t i o n " t e c h n i q u e the " e f f e c t i v e " r o o t development i n t u r f .  t o determine  Turf plugs are  c u t , a e r i a l growth i s trimmed t o t h e s o i l s u r f a c e , and t h e p l u g s a r e p l a c e d i n d a r k n e s s under c o n t r o l l e d t e m p e r a t u r e . A e r i a l growth produced i s p e r i o d i c a l l y c l i p p e d , d r i e d and weighed.  Dry m a t t e r produced d u r i n g t h e d a r k p e r i o d i s an index  of t h e f u n c t i o n i n g r o o t and food r e s e r v e s . t o recommend i t from t h e v i e w p o i n t  The method has much  o f convenience, and from  the f a c t t h a t i n o l d e r t u r f i t i s w e l l - n i g h i m p o s s i b l e t o d i s t i n g u i s h between l i v i n g and r e c e n t l y - d e a d  roots.  Obviously,  the method can c o n t r i b u t e l i t t l e t o t h e study o f t h e p h y s i o l o g y and morphology o f r o o t s i n s i t u . There appears t o be a h e i g h t e n e d i n t e r e s t i n r o o t techniques  i n t h e l a s t two y e a r s , b u t most p r o g r e s s  study  seems t o  be concerned w i t h m o d i f i c a t i o n s o f t h e g l a s s o r p l a s t i c window t e c h n i q u e s  d e s c r i b e d by F r e d e r i c k (1959)•  A l s o new  developments i n r o o t - w a s h i n g machines ( W i l l i a m and Baker, 1957), ( F r i b o u r g 1953) have r e s u l t e d i n g r e a t  savings  of labour  i n r o o t study where s o i l c o n d i t i o n s f a v o u r t h e i r use and seems t o make l a r g e - s c a l e e x a m i n a t i o n o f r o o t s o f t u r f p o s s i b l e . I t would appear t h a t a d d i t i o n a l methods f o r r o o t washing by machine may y e t be developed but a l l a r e l i k e l y t o s u f f e r from t h e f a c t t h a t v e r y f i n e r o o t s a r e not r e c o v e r e d  and from  the f a c t t h a t dead r o o t s , o r i n a c t i v e r o o t s , a r e not r e a d i l y  4 d i s t i n g u i s h e d from l i v i n g and f u n c t i o n i n g r o o t s .  Root  washing, t o o , i s o f l i m i t e d v a l u e i n s o i l s where t h e r e i s much coarse  o r g a n i c m a t t e r i n t o w h i c h f i n e r o o t s are p e n e t r a t i n g .  S e a s o n a l r o o t development and l e n g t h o f l i f e o f r o o t s According  t o Troughton (1957) d u r i n g the f i r s t few  months o f a p l a n t ' s l i f e ,  i f i t i s i n a s u i t a b l e environment,  the r o o t system grows v e r y r a p i d l y , the growth r a t e i n c r e a s i n g from z e r o j u s t b e f o r e g e r m i n a t i o n  t o a maximum some weeks  l a t e r , a f t e r which I t decreases.  The growth o f the r o o t s  c o n s i s t s o f an i n c r e a s e i n t h e i r number, w e i g h t , and l e n g t h , and v a r i e s c o n s i d e r a b l y between s p e c i e s . Remarkably few r o o t s t u d i e s b e g i n w i t h the s e e d l i n g development, and even fewer are comparative between s p e c i e s , or c o n s i d e r r o o t and top development c o n c u r r e n t l y . Plummer (1943) and o t h e r s have concluded  t h a t r o o t development  d u r i n g the f i r s t month o r two l a r g e l y determined  the  i n d i v i d u a l g r a s s e s ' success  which  or f a i l u r e .  Species  developed r o o t s r a p i d l y e s t a b l i s h e d stands much more r e a d i l y than those whose r o o t systems developed s l o w l y .  There seems  t o be g e n e r a l agreement w i t h Keim and Beadle (1927) and w i t h Simpson and Moore (1955), and Robocker, C u r t i s and Ahlgren  (1953) t h a t r o o t d e p t h and weight i n young  i s s i m p l y r e l a t e d t o c o l d and drought t o l e r a n c e . Kauter  grasses Although  (1933) ^ d Sprague (1933) found no c o n s i s t e n t a  trends  5  i n the d i s t r i b u t i o n of d r y m a t t e r between tops and r o o t s d u r i n g the e a r l y months of a g r a s s p l a n t ' s l i f e ,  Troughton  ( 1 9 5 6 ) s t a t e d t h a t the r e l a t i o n s h i p between r o o t s and  shoots  1  weight i n a steady s t a t e environment can be e x p r e s s e d by the k a l l o m e t r i c formula.  The f o r m u l a c o u l d be w r i t t e n y = bx  when y r e p r e s e n t s the weight of r o o t s and x the weight  of  the s h o o t s , b a c o n s t a n t e q u a l t o the v a l u e of y when the v a l u e of x was u n i t y and t o a c o n s t a n t e q u a l t o the r a t i o : l o g a r i t h m i c growth r a t e of y ( r o o t s ) l o g a r i t h m i c growth r a t e of x ( s h o o t s ) . The v a l u e s of x and y are o b t a i n e d by w e i g h i n g p l a n t s a t i n t e r v a l s over a p e r i o d of t i m e .  The v a l u e s of b and  were then o b t a i n e d by c a l c u l a t i o n or g r a p h i c a l means. the r e l a t i o n s h i p between the two s e r i e s of v a l u e s can e x p r e s s e d by t h i s f o r m u l a , then the p o i n t s produced  k  When be  on a  graph by p l o t t i n g t h e i r l o g a r i t h m i c v a l u e s a g a i n s t each o t h e r w i l l be a l o n g a s t r a i g h t l i n e .  The f o r m u l a can be used o n l y  w i t h p l a n t s measured on a t l e a s t t h r e e o c c a s i o n s i n a  season.  T i l l e r p r o d u c t i o n i n young g r a s s no doubt would c o m p l i c a t e measurements f o r s t o l o n s and rhizomes  a l t h o u g h o f t e n non-  p h o t o s y n t h e t i c and o f t e n below ground would have t o be c l a s s e d as stem. The  s u b j e c t of many s t u d i e s has been the time of r o o t  and shoot i n i t i a t i o n and growth.  In temperate l a t i t u d e s w i t h  p e r e n n i a l g r a s s e s most r o o t growth seems t o take p l a c e i n s p r i n g (Stuckey 1 9 ^ 1 ) , but some r o o t s are i n i t i a t e d  almost  e v e r y month o f the y e a r i f the s o i l i s not f r o z e n o r droughty. I t i s apparent t h a t a good d e a l o f r o o t growth o c c u r s d u r i n g the w i n t e r months i n f o r a g e s p e c i e s i n u n f r o z e n s o i l when no a e r i a l growth o c c u r s (Jacques and Schwass 1956)•  Commonly,  however, r o o t growth d i m i n i s h e s as a e r i a l growth i s produced i n s p r i n g and may cease a l t o g e t h e r by f l o w e r i n g time and d u r i n g seed m a t u r a t i o n . A g a i n , under c o o l , temperate and Schuurman (1950) and Troughton  c o n d i t i o n s , Goedewaagen (1951) concluded t h a t the  annual d e a t h and decay o f r o o t s of f o r a g e p l a n t s s t a r t e d i n May and c o n t i n u e d i n t o m i d - w i n t e r . Defoliation  o f the r o o t s o f f o r a g e g r a s s e s ,  e s p e c i a l l y when more than k0% o f the p h o t o s y n t h e t i c s u r f a c e i s removed, r e s u l t s , almost i m m e d i a t e l y , i n the c e s s a t i o n o f r o o t growth as C r i d e r (1955) has observed. w i t h n e a r l y a l l common temperate  T h i s i s the case  f o r a g e g r a s s e s except  o r c h a r d g r a s s where i t i s a second d e f o l i a t i o n , soon a f t e r the f i r s t , w h i c h seems t o r e s u l t i n r o o t growth stoppage a d d i t i o n a l l y , death.  Although t h i s simple  between top removal and r o o t growth stoppage  and,  relationship e x i s t s , the  broader i n t e r - r e l a t i o n s h i p between tops and r o o t development seems complex: no worker has r e p o r t e d , f o r example, t h a t the maximum growth o f r o o t s and shoots i s ever  coincidental.  7 Root i n t e r a c t i o n of crops growing i n a s s o c i a t i o n Competition  o c c u r s between p l a n t s f o r "elements" i n  the environment, and of t h e s e , most s t r i k i n g l y f o r w a t e r , l i g h t and c e r t a i n m i n e r a l elements.  I t i s often stated that  c o m p e t i t i o n i s more i n t e n s e between s p e c i e s of the same growth form than between those w h i c h are  dissimilar  (Weaver and Clements, 1938): t h i s c o m p e t i t i o n between smooth brome g r a s s , a r h i z o m a t o u s g r a s s and a l f a l f a , a t a p - r o o t e d legume, i s not as i n t e n s e as between Kentucky b l u e g r a s s , another  sod g r a s s , and smooth brome. W i t h i n c e r t a i n l i m i t s the g r e a t e r the d e n s i t y of a  p l a n t p o p u l a t i o n the s m a l l e r s h o u l d be the i n d i v i d u a l p l a n t and i n g e n e r a l the w e i g h t s of r o o t s p e r p l a n t s h o u l d  vary  i n v e r s e l y w i t h the r a t e of s e e d i n g and stand d e n s i t y ; (de P e r a l t a 1935,  Nedrow 1937,and o t h e r s ) .  The  literature  r o o t c o m p e t i t i o n , however, i s q u i t e l i m i t e d and lack definition.  on  conclusions  V e r y few s t u d i e s , f o r example, c o n s i d e r  r o o t development i n r e l a t i o n t o s o i l volume, s o i l a r e a , or pore space.  Nor have many s t u d i e s been attempted t o c l a s s i f y  the major element i n the c o m p e t i t i o n system such as or w a t e r or n u t r i e n t s .  light,  A h l g r e n and Aamodt (1939) i n a  of r o o t systems of f o u r common c o o l temperate f o r a g e  study  grasses  grown i n mixed and pure stands c o u l d not f i n d any c o n s i s t e n t t r e n d s i n r e l a t i o n s h i p s between r o o t s and s h o o t s , but d i d a t t r i b u t e some v a r i a t i o n s t o h a r m f u l r o o t i n t e r a c t i o n s .  Aberg, Johnson and W i l s i e (194-3) i n v e r y s i m i l a r  experiments  found no e v i d e n c e o f e i t h e r m u t u a l l y b e n e f i c i a l o r a n t a g o n i s t i c a s s o c i a t i o n s ; r e s p o n s e s were m e r e l y o f t h e "compensating" Troughton  type.  (1956) d i d , however, i n a c a r e f u l s t u d y f i n d r o o t  i n t e r a c t i o n s between p e r e n n i a l r y e g r a s s and t i m o t h y . The r o o t i n t e r a c t i o n s o f g r a s s and legume growing i n a s s o c i a t i o n i s u n d o u b t e d l y more complex than t h o s e o f g r a s s and g r a s s because  o f t h e added i n v o l v e m e n t o f n i t r o g e n  i n t h e r o o t n o d u l e s o f t h e legume. y i e l d s i n c o n c l u s i v e statements:  fixation  A g a i n a modest l i t e r a t u r e  R u s s i a n workers  (Duhanin 1940),  Ivanov (1950), Schwendiman, H a f e n r i c h t e r and Law (1953), and R o b e r t s and Olson (194-2) found an i n c r e a s e i n r o o t p r o d u c t i o n p e r u n i t a r e a when g r a s s and legume were grown i n association.  Troughton  (1956) found t h a t one p l a n t o f w h i t e  c l o v e r grown w i t h two t o s i x p l a n t s o f t i m o t h y o r p e r e n n i a l r y e g r a s s d i d n o t a f f e c t t h e growth o f t h e g r a s s r o o t s i n twentytwo weeks' growth from seed.  On t h e o t h e r hand, Jacques (1943)  and a few o t h e r s have r e c o r d e d s m a l l e r r o o t w e i g h t s f o r g r a s s e s grown i n t h e p r e s e n c e o f a legume.  Chemical c o m p o s i t i o n o f r o o t s P l a n t p h y s i o l o g i s t s and p l a n t c h e m i s t s have l o n g been i n t e r e s t e d i n " r e s e r v e " m a t e r i a l s as opposed t o " s t r u c t u r a l " materials.  There has been, moreover, a l o n g - s t a n d i n g view t h a t  r e s e r v e s a r e d e p l e t e d d u r i n g p e r i o d s o f r a p i d f o r a g e growth, d u r i n g w i n t e r as r o o t s a r e extended, and f o l l o w i n g  defoliation.  S e a s o n a l v a r i a t i o n has been noted i n the l e v e l s o f nitrogenous  e x u d a t e s , and m i n e r a l c o n s t i t u e n t s i n r o o t s b u t ,  as Weinman (19U8) and Troughton (1957) p o i n t o u t , much c o r r e l a t i v e work i s needed b e f o r e made.  g e n e r a l i z a t i o n s can be  C u r i o u s l y l i t t l e work on t h e " s t r u c t u r a l "  constituents  of r o o t s e x i s t s i n the f o r m a l l i t e r a t u r e o f p l a n t b u t , inasmuch as t h e m i c r o b i o l o g i c a l d e g r a d a t i o n constituents i n s o i l i s of considerable  physiology o f these  s c i e n t i f i c and  t e c h n i c a l i n t e r e s t , t h e r e l e v a n t l i t e r a t u r e , viewed i n a broad sense i s l a r g e .  L i g n i n , as one o f the i n t e r e s t i n g  s t r u c t u r a l components o f r o o t s , i s t h e s u b j e c t o f e x h a u s t i v e r e v i e w s o f G o t t l i e b and H e n d r i c k s (19U5), and by Brauns and Brauns (i960).  B o l l e n and Lee (1957) a r e o f t h e view t h a t the  s t r u c t u r a l l i g n i n - c e l l u l o s e complex i s m e t a b o l i z e d s o i l micro-organisms.  Kholodnyi  s l o w l y by  (1951) b e l i e v e s t h a t  soil  l i g n i n , as i t decomposes, r e l e a s e s r o o t growth s t i m u l a t i n g s u b s t a n c e s but a p p a r e n t l y he does not s p e c i f y whether o r not t h e s e a r e d e r i v e d from r o o t o r shoot l i g n i n . '  A l t h o u g h Weinman  (19^6) does n o t b e l i e v e t h a t h e m i c e l l u l o s e n o r m a l l y considered converted  as ' r e s e r v e  1  s h o u l d be  i n e t i o l a t e d Bromus c a r i n a t u s i t i s  t o simpler substances.  A great deal of v a r i a t i o n  a c t u a l l y e x i s t s i n the views o f w o r k e r s as t o t h e r e l a t i v e importance o f t h e v a r i o u s c a r b o h y d r a t e f r a c t i o n s as " r e s e r v e s " a c c o r d i n g l y t h e r e i s a good d e a l o f v a r i a t i o n i n the c h e m i c a l p r o c e d u r e s used i n t h e d e t e r m i n a t i o n  of reserve  carbohydrates.  Weinman (19U6) and Dale Smith (1962) have commented b r i e f l y  10 on the p r o c e d u r e s i n use. Because o f t h e i r v e r y p r o b a b l e recovery  of forage  importance i n t h e  crops f o l l o w i n g g r a z i n g or mowing, i n  c o m p e t i t i o n w i t h weeds, i n w i n t e r and summer h a r d i n e s s , seasonal accumulation  o f r e s e r v e c a r b o h y d r a t e s has a t t r a c t e d  a good d e a l o f a t t e n t i o n .  D e s p i t e a good d e a l o f i n t e r e s t ,  however, t h e number o f s t u d i e s are few, 1937,  Weinman 1948, Brown 1943).  (McCarty 1938, Klapp  Most o f the s t u d i e s r e l a t e  t o e s t a b l i s h e d p e r e n n i a l f o r a g e crops and,  In general, i t  seems t h a t c a r b o h y d r a t e r e s e r v e s are s t o r e d i n r o o t s  during  p e r i o d s o f slow herbage growth i n s p r i n g , summer, and,  esp-  e c i a l l y , e a r l y autumn, t h a t t h e s t r u c t u r a l m a t e r i a l s a r e p o s s i b l y l e s s important  and l e s s abundant i n r o o t s t h a n i n  t o p s , and t h a t r o o t s are i m p o r t a n t substances.  storage  A c t u a l l y the c h e m i s t r y  organs f o r r e s e r v e  of roots i s not very w e l l  known, a l t h o u g h d o u b t l e s s t h e s e g e n e r a l i z a t i o n s are  valid.  However, i t i s i n t e r e s t i n g t o note t h a t r e c e n t l y (Baker 1955, 1  6l)  a t the Grassland  Research S t a t i o n , a t Hurley,  England,  b a s a l stems, l e a v e s , and p l a n t crowns were found t o be q u i t e as i m p o r t a n t  f o r s t o r a g e as r o o t s i n c e r t a i n g r a s s e s , and  t h a t r o o t s f u n c t i o n e d p r i m a r i l y i n the uptake o f m i n e r a l n u t r i e n t s and w a t e r . Reserve substances i n g r a s s r o o t s a r e c o n s i d e r e d mainly  carbohydrates,  e.g. sugars,  t o be  fructosons, dextrins,  s t a r c h p e n t o s a n s , h e m i c e l l u l o s e , and t r u e c e l l u l o s e a r e considered  t o be l a r g e l y s t r u c t u r a l .  (Weinman 1948).  C e r t a i n l y p l a n t s l o s e , i n the p r o d u c t i o n of tops i n d a r k n e s s , c a r b o h y d r a t e s of the former c a t e g o r y and r e l a t i v e l y c a r b o h y d r a t e i n the l a t t e r c a t e g o r y . 1938)  Some workers  little (McCarty  believe that, f o r a given species, root s t r u c t u r a l  m a t e r i a l s d i f f e r g r e a t l y from those of the a e r i a l p a r t s , but singularly l i t t l e establish this  c h e m i s t r y has been u n d e r t a k e n w h i c h would  point.  12 EXPERIMENTATION P r o j e c t 1 - D i r e c t o b s e r v a t i o n i n s o i l of growing r o o t s . a)  Object To observe r o o t s i n s o i l d i r e c t l y has been the g o a l  many s t u d i e s .  of  Thus f a r a l l methods developed can be s e r i o u s l y  c r i t i c i z e d , f o r a l l d i s t u r b the s o i l , or i n o t h e r ways c r e a t e undesirable  changes i n the r o o t environment or s a c r i f i c e  the  r o o t or p a r t s of r o o t s . G l a s s or p l a s t i c windows have been t r i e d by a number of workers f o r the study of r o o t s i n p l a c e , ( C r i d e r 1955) 196l)  and  (Lavin  o t h e r s , and d e s p i t e d e f i c i e n c i e s i n method, are  u s e f u l f o r r a t e of r o o t growth s t u d i e s , s p e c i e s i n t e r a c t i o n s t u d i e s , and  so f o r t h .  I n our s t u d i e s g l a s s "wafers" were used  w h i c h c a l l e d f o r a m i n i m a l s o i l volume, the p o i n t b e i n g r o o t r e s p o n s e s would be more r a p i d l y p e r c e i v e d and  that  that  emanations f r o m s m a l l q u a n t i t i e s of r a d i o t r a c e r s , dyes, e t c . would not be b)  " l o s t " i n a l a r g e s o i l mass.  Method 92" x 16 i n c h window-glass r e c t a n g l e s were h e l d 1/4  inch  a p a r t i n t w i n - g r o o v e d wooden frames (see P i g . l ) . F i b e r g l a s s wool was lacuna  p l a c e d t o a d e p t h of \ i n c h a t the bottom of the  so t h a t s o i l c o u l d be h e l d and f r e e movement of water  permitted.  Nicholson  an 8-mesh s c r e e n , and plates.  The  loam s o i l was  a i r d r i e d , screened t h r o u g h  c a r e f u l l y f e d i n t o the l a c u n a between the  p l a t e s were tapped l i g h t l y t o be a s s u r e d  that  the  13  s o i l was compacted f a i r l y u n i f o r m l y . per i n c h .  The "wafers" were p l a c e d v e r t i c a l l y on a t h i n l a y e r  of m o i s t e n e d v e r m i c u l i t e and covered p l a s t i c sheets t o p r e s e n t interface.  Seeds were p l a n t e d 3  each s i d e w i t h b l a c k  l i g h t from r e a c h i n g t h e s o i l - g l a s s  The s o i l was kept m o i s t by w a t e r i n g e v e r y  other  day. c)  Observations The  and d i s c u s s i o n  b l a c k p l a s t i c sheets were opened p e r i o d i c a l l y t o  examine t h e r o o t systems o f g r a s s and c l o v e r .  This  technique  a l l o w e d t h e worker t o observe t h e r o o t system f r o m b o t h sides of the glass p l a t e s . the narrow p l a t e s p r o b a b l y  Although  t h e r o o t s grown between  a c t somewhat d i f f e r e n t l y from  those  i n n a t u r e t h e r e i s some v a l u e t o t h i s method ( F r e d e r i c k 1958). Some f e a t u r e s o f g e n e r a l morphology o f t h e r o o t systems can be seen and L a v i n (1961) has observed and measured t h e r a t e of r o o t growth by a s i m i l a r The  technique.  r o o t systems o f p l a n t s s t u d i e d , v i z . , p e r e n n i a l  r y e g r a s s , by t h i s method were photographed ( F i g . l ) . The photos g i v e a g e n e r a l i d e a o f t h e roots-system-arrangement under t h e s o i l c o n d i t i o n s b u t p l a i n p o l a r i z e d l i g h t would be necessary  t o o b t a i n good r e c o r d s  P a r t r i d g e (l9ho),  (Haas and R o g l e r  S c h u l t z ( 1 9 5 6 ) , and P a r m e i j e r  1953),  (1956)  photographed t h e r o o t systems o f v a r i o u s p l a n t s i n s i t u and  14 showed t h a t t h e p i c t u r e s f r o m m u l t i d i m e n s i o n a l p r o f i l e  study  and those f r o m in_ s i t u study were s i m i l a r . No attempt was made t o measure t h e d a i l y r a t e of r o o t growth.  The r o o t s o f b o t h r e d c l o v e r and r y e g r a s s  the bottom-most p a r t o f t h e "wafers" emergence.  reached  o n l y t h r e e weeks a f t e r  Fig. 1. -  Roots of 10-day old perennial ryegrass plant showing at the between glass-soil interface. Note the roots do not necessarily follow the interface.  16 P r o j e c t 2. - D i r e c t o b s e r v a t i o n o f p o s s i b l e i n t e r a c t i o n s o f g r a s s and legume r o o t s i n . s i t u . a)  Object; 32 P as a r a d i o t r a c e r substance  i n r o o t s was used f a i r l y  s u c c e s s f u l l y by F r e d e r i c k (1959) and o t h e r s ( H a l l e_t aJL 1953), ( B u r t o n e_b a l _ 1954, 1957), (Boggle et_ a l _ 1958, i960) i n t h e s t u d y o f r o o t d i s t r i b u t i o n o f g r a s s e s i n the f i e l d .  I t was  hoped t h a t the use o f X-ray photos o r r a d i o t r a c e r s w i t h more 32 e n e r g e t i c emanations than P  c o u l d be used w i t h the  wafer t e c h n i q u e " d e s c r i b e d above.  "thin-  The p o s s i b i l i t y o f u s i n g  r a d i o t r a c e r s such as r a d i o - i o d i n e c o u l d n o t be undertaken because o f d i f f i c u l t i e s i n o b t a i n i n g l a n d t e n u r e  guarantees,  and hence the d i r e c t i o n o f the work was a l t e r e d somewhat. A l t h o u g h the b e n e f i c i a l e f f e c t s o f a s s o c i a t e d growth of g r a s s and legumes have been on r e c o r d f o r a v e r y l o n g time and on a_ p r i o r i grounds, one must assume t h a t i m p o r t a n t  inter-  a c t i o n s between t h e i r r o o t s o c c u r , the n a t u r e o f the i n t e r a c t i o n s has never been c l e a r l y e s t a b l i s h e d . Undoubtedly i n d e a t h and decay o f r o o t s o f g r a s s and legume, and in_ v i t r o , m a t e r i a l s such as amino a c i d s , C 0 e t c . are r e l e a s e d w h i c h are i m p o r t a n t , 2  but r o o t - i n i t i a t e d i n t e r a c t i o n s between g r a s s and legume o c c u r l o n g b e f o r e o b s e r v a b l e d e a t h and decay o f r o o t s .  I n the hope  t h a t m o r p h o l o g i c a l rapprochements o f g r a s s and legume r o o t s c o u l d be observed by the t h i n wafer t e c h n i q u e , i n t e r p l a n t i n g s of g r a s s and legume were u n d e r t a k e n . a t i o n s are d e s c r i b e d below.  The t e c h n i q u e and observ-  b)  Method The  method was  s i m i l a r t o the "wafer" t e c h n i q u e  c r i b e d i n P r o j e c t 1. Red  c l o v e r and p e r e n n i a l r y e g r a s s  were p l a c e d a l t e r n a t e l y i n the c)  Observations The  wafers.  and d i s c u s s i o n  Roots of b o t h p l a n t s reached the bottom of  the w a f e r p l a t e s i n about t h r e e weeks and roots outside. 1"  seeds  mixed r o o t systems of c l o v e r and r y e g r a s s were  observed d a i l y .  about  des-  s t a r t e d t o send the  T h i s means t h a t the r o o t system extended a t  p e r day or more.  Weaver  (1926)  notes t h a t r o o t  e l o n g a t i o n i n g r a s s s e e d l i n g s of common g r a s s e s of -§•" a day i s a good r a t e .  The  r o o t system of b o t h r y e g r a s s  c l o v e r moved down s i d e by s i d e i n d i f f e r e n t l y .  and  Though the  seeds of c l o v e r germinated n e a r l y two days ahead t h e y d i d not show much advantage i n e l o n g a t i o n or i n o c c u p y i n g s o i l volume.  The  o b s e r v a t i o n p e r i o d was  but i t seemed t h a t b o t h r o o t systems may  relatively  the short  grow s i d e by s i d e .  Because r o o t s of g r a s s c o u l d not r e a d i l y be d i s t i n g u i s h e d from r o o t s of legumes, o b s e r v a t i o n was  of n e c e s s i t y c a s u a l ,  but i t seems t h a t no s p e c i f i c a t t r a c t i o n or r e p u l s i o n i s involved.  However, t h i s does not n e c e s s a r i l y b e l i e  f i e l d o b s e r v a t i o n by Haynes, e t  al.  (1956),  t h a t the r o o t  growth of c o r n tended t o be i n the d i r e c t i o n of no occupancy.  The  the  root  r o o t system of g r a s s d i d not appear t o be  more s u p e r i o r i n " p e n e t r a t i n g a b i l i t y " t o legume. ( F i g . 2 ) . T h i s o p i n i o n i s supported  by the o b s e r v a t i o n s  of T a y l o r  (i960) (a and b ) , who a l s o f i n d s t h e p e n e t r a t i n g a b i l i t y o f legume r o o t s t o be n o t s i g n i f i c a n t l y g r e a t e r than those o f non-legumes.  Nevertheless,  i n t e r a c t i o n may take p l a c e i n  the v i c i n i t y o f r o o t h a i r s , i . e . i n t h e r h i z o s p h e r e  zones.  Rosene and W a l t h a l l (1949) r e p o r t e d t h e v e l o c i t y o f water a b s o r p t i o n by i n d i v i d u a l r o o t h a i r was n o t a t t h e same r a t e ; legume r a t e s were h i g h e r than g r a s s r a t e s .  When t h e r a t e o f  a b s o r p t i o n i s h i g h e r , n a t u r a l l y the amount o f n u t r i e n t i n t a k e would be h i g h e r p r o v i d i n g t h a t t h e amount .<3f) r o o t h a i r was  constant.  Dittmer  (1937, 1938, 1949, 1959, a and b)  r e p o r t e d t h e t o t a l s u r f a c e area o f 4321.30 square f e e t o f 14,335,568,288 r o o t h a i r s o f a matured s i n g l e w i n t e r r y e plant.  However, t h e r e i s no r e p o r t f o r a legume p l a n t on a  similar basis.  Fig. 2 - Root systems of red clover and perennial ryegrass, two weeks old, growing side by side.  The primary  roots of red clover are thicker than those of the perennial ryegrass at the same age.  20 P r o j e c t 3 - The development of a r o o t washing machine. When i t was r e a l i z e d t h a t work w i t h r a d i o t r a c e r s c o u l d not be c o n t i n u e d ,  the l i t e r a t u r e r e l a t i v e t o t e c h n i q u e s  used  i n s t u d y i n g t h e r o o t s of f o r a g e crops and s p o r t s t u r f by washing and/or e x c a v a t i o n t e c h n i q u e s techniques  was examined.  The main  a r e simple enough, b a s i c a l l y , and c o n s i s t o f (a)  washing away s o i l from r o o t s or (b) p l o t t i n g r o o t s as they appear i n s u c c e s s i v e p r o f i l e s , b u t dozens of m o d i f i c a t i o n s and  combination  of these occur and many v a r i a t i o n s I n equip-  ment used have been p r o p o s e d . I t appeared, from t h e l i t e r a t u r e survey,  that a root  washing machine developed and used a t the G r a s s l a n d R e s e a r c h I n s t i t u t e , a t H u r l e y , E n g l a n d , worked w e l l and would be g e n e r a l l y u s e f u l .  A c c o r d i n g l y , a machine s i m i l a r t o t h a t  used a t t h e I n s t i t u t e was c o n s t r u c t e d . and  I t i s d e s c r i b e d below  comments on i t s u s e f u l n e s s a r e made. a) Method A machine f o r t h e r o o t washing s i m i l a r t o t h e one used  by W i l l i a m s and B a k e r (1957), o n l y d i f f e r e n t i n t h e d e t a i l s , was c o n s t r u c t e d .  ( F i g . 3).  The machine was mounted on t h e  angle i r o n frame, I t c o n s i s t e d of f o u r washing t r a y s .  A 1/4  H.P. e l e c t r i c motor was used t o d r i v e t h e t r a y s by means o f rubber b e l t s .  The t r a y s t u r n e d a t 60 r.p.m.  movable from t h e f u n n e l . Inches,  Each t r a y was  The d i a m e t e r of the t r a y was 12  t h e depth 6 i n c h e s , and 3-mesh g a l v a n i z e d  screen  Fig. 3 -  General view of the root washing machine.  22  for  the s u p p o r t s .  31-mesh b r a s s s c r e e n was used on the bottom.  Two f a u c e t s were f i x e d above each t r a y ; the i n t e n s i t y and f l o w of the streams of water c o u l d be r e g u l a t e d by the f a u c e t s . (Pig.  4).  b)  O b s e r v a t i o n s and d i s c u s s i o n The machine worked w e l l w i t h samples l i m i t e d i n s i z e .  The s o i l - r o o t samples from the f i r s t h a r v e s t b a r l e y ( t o be r e f e r r e d t o l a t e r ) were washed w i t h the machine a f t e r s e c t i o n s of s o i l had been crumbled.  The machine c o u l d not handle the  l a r g e r sample s i z e s e f f e c t i v e l y , i . e . samples w h i c h were l a r g e r than the t r a y i t s e l f .  However, the machine i s g e n e r a l l y v e r y  e f f e c t i v e f o r r o o t washing and one can s u p p o r t P r i b o u r g (1953) who found t h a t a r o o t washing machine was 18 t i m e s f a s t e r i n washing 100 r o o t samples of L a d i n o c l o v e r than manual washing. I t was found t h a t i f dead r o o t s or b i t s of wood, e t c . were mixed i n the s o i l - r o o t sample, the machine-washed were not c l e a n and time had t o be spent i n c u l l i n g .  samples It is  suggested t h a t an "up and down" m o t i o n , ( P r i b o u r g 1953)  seen  i n o l d - t y p e washing machines might be u t i l i z e d i n f u t u r e c o n s t r u c t i o n , i . e . a l t e r n a t e immersion and removal of the sample from a w e l l of water might wash more u n i f o r m l y and gently.  Fig. k  - View from top showing rotating containers and adjustable water jets.  24 P r o j e c t 4 - Comparative r o o t development o f an annual g r a s s ( b a r l e y Hordeum sativum) and a p e r e n n i a l g r a s s ( o r c h a r d g r a s s D a c t y l i s g l o m e r a t a ) from seed. a)  Object Although  i t i s g e n e r a l l y acknowledged t h a t t h e r o o t  system produced by an annual i s much s m a l l e r than t h a t produced by a p e r e n n i a l g r a s s i n a g i v e n season, a s e a r c h o f the l i t e r a t u r e d i d n o t r e v e a l any t r i a l s where t h e two r o o t systems had been produced under comparable c o n d i t i o n s . B a r l e y and o r c h a r d g r a s s were seeded i n s p e c i a l boxes s e t i n t h e f i e l d a t about t h e same time i n e a r l y summer.  Periodically  the r o o t p r o d u c t i o n was a s s e s s e d by washing c e r t a i n r e p l i c a t e s f r e e o f s o i l , d r y i n g , and w e i g h i n g b)  the product.  Method Boxes were c o n s t r u c t e d o f plywood 12" x 12" x 12" and  19-mesh n y l o n screen f i x e d on t h e bottoms. was screened  Nicholson  t o remove f i n e r o o t s , o l d r o o t s , e t c .  40 boxes were e s t a b l i s h e d t o b a r l e y ; o n e - h a l f were at  soil  In a l l , fertilized  t h e r a t e o f 1000# p e r acre (15 g. p e r box) w i t h 10-20-10  m i n e r a l f e r t i l i z e r , and o n e - h a l f were n o t f e r t i l i z e d .  The  f e r t i l i z e r was t h o r o u g h l y mixed w i t h t h e s o i l p r i o r t o adding t h e s o i l t o t h e boxes.  The boxes were c a r e f u l l y p l a c e d  so t h a t t h e r i m s were a t g e n e r a l s o i l l e v e l and c a r e f u l l y f i l l e d with f e r t i l i z e d design r e q u i r e d .  o r u n f e r t i l i z e d s o i l as t h e f i e l d  ( F i g s . 5 and 6).  25  B a r l e y seed was sown on May 19, 1 9 6 1 , and when t h e p l a n t s were 1-|" h i g h t h e y were t h i n n e d t o 4 p e r box.  Water  was l i g h t l y and u n i f o r m l y a p p l i e d on a l t e r n a t e days throughout t h e growing  season.  Three v a r i e t i e s o f o r c h a r d g r a s s , i . e . L a t a r , D a n i s h , and S-143 v a r i e t i e s , were seeded i n 48 boxes f i l l e d w i t h s o i l f e r t i l i z e d a t 1000# p e r a c r e , i n t h e same f a s h i o n as f o r barley. of  Because o f time i n p r e p a r a t i o n and t h e l a t e  arrival  the seed o f t h e L a t a r v a r i e t y , s e e d i n g d i d not t a k e p l a c e  u n t i l June 14.  At t h a t time t h e seed was b r o a d c a s t a t t h e  r a t e of 170 l b s . p e r a c r e (1.8 grams p e r b o x ) .  Seeds were  covered w i t h 1/4"- s o i l a f t e r s e e d i n g . B a r l e y r o o t s and t o p s from f o u r boxes were washed, d r i e d and weighed i n each o f f i v e o c c a s i o n s d u r i n g t h e growing  season.  Orchard g r a s s r o o t s and t o p s from f o u r boxes  were washed, d r i e d and weighed on each of f o u r o c c a s i o n s d u r i n g t h e growing c)  season.  O b s e r v a t i o n s and r e s u l t s B o t h b a r l e y and o r c h a r d g r a s s developed n o r m a l l y  t h r o u g h t h e growing season and d i s e a s e and i n s e c t damage were m i n i m a l . I t i s n o t a b l e t h a t t h e t o p / r o o t r a t i o s i n t h e annual g r a s s , ( b a r l e y ) i n c r e a s e s t e a d i l y throughout t h e growing season b u t those o f the p e r e n n i a l g r a s s ( o r c h a r d g r a s s ) remain r e m a r k a b l y c o n s t a n t t h r o u g h t h e growing  season  Fig. 5  -  Barley plants i n 12  M  x 12" x 12" boxes  as seen i n the f i e l d .  Fig. 6  -  Removing a barley container prior to harvesting tops and washing roots.  28  (Figs.  7 and  8).  This  observation  t o mean t h a t , a l t h o u g h t h r o u g h the  these  materials  close  t o the  tend  regions  matter l e v e l s  one-half as  (Figs.  of t h e i r  and  most  the  On  the  other  orchard  of plants i t has  organic  hand, i n i t s f i r s t  grass  elaborated  of  Annuals,  are poor c o n t r i b u t o r s t o the  soils.  grow  reserve  aerial parts  elaboration.  i s a l s o notable' t h a t the  harvest,  root,  to remain i n the  of t h e i r  diminishing  fall  roots  do  plant  organic  contributes  matter to  the  root. It  and  of  of development,  soil  of annual grasses  t r a n s l o c a t e d t o the  l o n g been r e c o g n i s e d ,  about  roots  g r o w i n g s e a s o n , m i n i m a l amounts o f  •arbohydrates are  year  the  i s generally interpreted  had  i n w e i g h t by  the  yield  w e l l exceeded  9 and  10).  of  late  orchard  those  b a r l e y r o o t was dough s t a g e . grass,  of the  By  dying late  both i n top  annual  cereal.  and  29  ^  Fig. 7 • -  T o p / r o o t r a t i o s a t s e v e r a l growth s t a g e s f o r f e r t i l i z e d and u n f e r t i l i z e d plants.  i  barley-  LATAR  o o cc s CL O  DANISH  0 5 0  I  6  10  1  1  AND  Fig, 8~ -  GRAND  1  EARLY FALL  1  SAMPLING DATES STAGES OF GROWTH  Top/root ratios at several growth stages for Latar, Danish and S-143 orchard grass varieties.  S-143  ORCHARDGRASS  (FERTILIZED)  TOP  Aug 8  l  25 days  ROOT  BARLEY  (FERTILIZED) MAX  Aug 5  46 days  MAX  0  i  30  WT. TOP  WT ROOT  i  60  i  90  i  120  i  150  i  180  Gms  Fig. 9 -  Comparison of root and top development i n mid-season of an annual and perennial grass i n the year of seeding.  32  S-143  ORCHARDGRASS  Sept. 2 6 7 2 days  I MAX. WT  BARLEY Sept. I 8 119 days  (FERT.) JVIAX WT. TOP 1 ROOT  ( FERT. ) TOP  ROOT  30  60  90 Gms  120  150  180  Fig, 10 - Comparison of root and top development i n late season of an annual and perennial grass i n the year of seeding.  33 5.  Project  - Time o f o n s e t grass  a)  to the  seedings  easily  or  stage  m i g h t be  forage  seedings  the  s e e d l i n g develops, soil,  (1956)  and  surface on  areas  and  factors  and  stage.  n u t r i e n t s are  i n the  never  pore  first  seed  "carry"  water are  The  stands  and  competition,  stage  in  tremendous  i n a common s o i l , to develop  contention.  may  i . e . competition  would,  a t an  early  r a t e s which  i n many " r a t e s o f s e e d i n g " this  Black  shading early  In view of the  expected  drawn  competitive reactions  l a r g e range i n seeding  i n grass  decided  be  As  soon  atmosphere, a l t h o u g h  space areas  be  of i t s development.  as n u t r i e n t s and  Root  not  assumed t h a t i n  at a s u r p r i s i n g l y  water,  seem t o s u p p o r t  I t was  stages  i n the  grounds, not  observations and  not  s o l u t e s and  satisfactory would  be  o t h e r s have shown t h a t l i g h t  a_ p r i o r i  seedling  i t may  reserve foods  initial  seedling stands.  soil  forage  that "competition" w i l l  seem t h a t t h e  soil,  become i m p o r t a n t  for  in  literature  i n t e r a c t i o n s between s e e d l i n g s must  I t would i n the  when w a t e r and  i n general  s e e d l i n g i n the  occur.  at which competition  I t i s apparent  the  from the  some u n c e r t a i n t y i n t h e  expected  d e f i n e d but  standard  dense  forage  stands.  seems t o be  time  limiting.  occur  in  Object There  as  of s e e d l i n g competition  experiments  Nonetheless,  critical  s e e d l i n g r e a c t i o n s are remarkably  t h e r e f o r e , t o examine t h e  give  time  of  few,  onset  34  of  seedling root  competition  i n a p r e l i m i n a r y way.  b) Method Seeds o f p e r e n n i a l r y e g r a s s sown i n b o x e s l i k e in  the f i e l d .  acre  those  Seeding  ( a common f o r a g e  Valley),  p r e v i o u s l y d e s c r i b e d , and s e t o u t  r a t e s were e s t a b l i s h e d a t 2 5 l b s . p e r seeding  r a t e i n t h e Lower F r a s e r  a t 100 l b s . p e r a c r e  ( a r a t e commonly u s e d f o r  l a w n s ) and a t 400 l b s . p e r a c r e o c c a s i o n a l l y by g r e e n s - k e e p e r s F i f t e e n b o x e s were f e r t i l i z e d 10-20-10 m i n e r a l Seeding placed day.  on A u g u s t  i n the f i e l d Thirty-six  aerial cut  fertilizer,  took place  soil,  c)  dried,  and f i f t e e n were n o t 15, 1961.  w e i g h e d and  irrigated  every  other  3" i n h e i g h t )  dried  were  and w e i g h e d . free  counted.  p e r box, t h e w e i g h t s o f t o p s and and t h e a v e r a g e w e i g h t s i n Table  of s i n g l e  1 and F i g u r e 1 1 .  t h e s e e d l i n g p o p u l a t i o n s p e r box was done  stubs  was much e a s i e r ,  The boxes were  (about  t o p and r o o t a r e g i v e n  from the r o o t  fertilized.  and d i s c u s s i o n  s e e d l i n g counts  Counting  with  t h e s e e d l i n g r o o t s were washed  the top/root r a t i o , 1  seedings).  a t 1000 l b s . p e r a c r e  a t ground l e v e l ,  Observations  seedlings  turf  d a y s a f t e r p l a n t i n g and c o u n t i n g , t h e  scissors  The roots,  f o r special  and s p r i n k l e r  Immediately a f t e r w a r d s , of  ( a r a t e known t o be u s e d  p o r t i o n s of the seedlings  with  ( L o l i u m p e r e n n e ) were  r a t h e r than  particularly  before  harvest  since i t  i n t h e dense s t a n d s .  The  35 number the  of seedlings  roots;  dried  i n a population  t h i s was  was  done a f t e r t h e r o o t  and w e i g h e d .  The r o o t  mass was  mass  stub  made t h e r o o t s  and e a s y t o p u l l o u t .  Several First  striking  i t i s t o be n o t e d  that  ratio  i n nearly  a l l b o x e s and s u g g e s t s  of r o o t  recovered  was much t h e same b y t h e method  is  that  of treatment.  the s e e d l i n g  (25 l b s . p / a ) was  difference in the  of  observation  seeding  than a t the h e a v i e r  and u n f e r t i l i z e d  rates.  little  emergence, i . e . t h e numbers  fertilized  used  of  seedlings  b o x e s were  about  same. At  a l l rates  production The  much s m a l l e r  the percentage  striking  as w o u l d be e x p e c t e d , made  i n seedling  the comparable  t h e most  s i z e a t t h e low r a t e  very  Fertilizer,  Next,  that  data.  i s very  similar  regardless  Soaking  from the t a b l e d  the top/root  was  i n hot water,  pulled free.  i t e m s emerge  counting  o f a box  soaked  s q u e e z e d d r y , and e a c h elastic  and r o o t  checked by  rate The  mediate  t o f e r t i l i z e r was of  relatively  seeding  rate  boxes.  a t t h e 400  were  greatest  o f 100#per  obtained  acre  roots.  a t the  In both f e r t i l i z e d  l b s . per acre  rate  and  lowest  i t may  and  unfertilized  the s e e d l i n g s ,  t h e same a v e r a g e  rate;  at the i n t e r -  i n both f e r t i l i z e d  numerous, were a b o u t seeding  much l a r g e r  seeding.  largest seedlings  unfertilized soils  a d d i t i o n r e s u l t e d i n the  of l a r g e r tops but not i n very  response  lowest  fertilizer  though  s i z e as t h o s e a t t h e  be s i g n i f i c a n t ,  nonetheless,  TABLE I TIME OF ONSET OF SEEDLING- COMPETITION IN FORAGE GRASS STANDS FERTILIZED  Box No.  Seeding Rates  25 pounds per acre  X  - S.E.1 2 3 4 5  - S.E.-  X ± S.E.X  Weight of Roots (gm.)  3.2573 1.8189 1.4620 1.3970 2.2926  0.8774 1.4796 0.6442 0.6652 1.5483  Top/Root Ratio  Av. Wt. Single Top (gm.)  Av. Wt. Single Root ' (gm.)  3.7124 1.2293 2.2694 2.1001 1.4807  0.0290 0.0166 0.0125 0.0128 0.0193  .00783 .01357 .00550 .00610 .01301  0.0180  .00920  499 486 458 487 464  17.020 18.320 15.920 13.960 15.785  6.7522 6.7382 5.4126 5.1217 5.4896  0.0341 0.0377 0.0347 0.0287 0.0340  .01353 .01386 .01181 .01051 .01183  0.0338  .01231  0.0129 0.0109 0.0106 0.0090 0.0100  .00537 .00443 .00436 .00406 .00386  0.0107  .00442  2.5206 2.7188 2.9412 2.7256 2.8754  478.8 16.201 5.9028 ±7.678 ±0.7301 ±0.3528  X  400 pounds per acre  112 109 117 109 119  Weight of Tops (gm.)  113.4 2.0455 1.0429 ±2.062 ±0.3422 ±0.1949  X  100 pounds per acre  X  1 2 3 4 5  Plant No.  1 2 3 4 5  1638 1644 1657 1705 1708  21.180 17.965 17.560 15.420 17.195  8.805 7.290 7.235 6.930 6.595  1670.4 17.864 7.371 ±15.05 ±0.9359 ±0.3795  2.4054 2.4643 2.42702.2251 2.6072  TABLE I - c o n t d 1  NON - FERTILIZED  Box No.  Seeding Rates  25 pounds per acre  1 2 3 4  X ± S.E.A  100 pounds per acre  X - S.E.^  110 120 118 101  1 2 3 4 5  0.5199 0.6354 0.6216  0.4215  0.5496 -0.1575  383  10.375  421 494 476 446  . 444 ±19.69  1 2 3 4 5  Weight of Tops (gm.)  112.5  ±4.330  X - S.E.X  400 pounds per acre  Plant No.  1480 1605 1778 1660 1662  1637 ±48.32  12.432 13.500 13.140 14.000  12.690  ±6.325 9.858 12.535 12.160  14.858 15.830  13.0482  ±1.055  Weight of Roots (gm.)  Top/Root Ratio  Av. Wt. Single Top (gm.)  Av. Wt. Single Root (gm.)  0.3823 0.4795 0.4692 0.3738  1.3599 1.3251 1.3248 1.1276  .00472 .00529 .00526  .00347  .00417  .00370  0.0049  0.4264 ±0.02646  4.3752 4.6470 5.5690  6.2103 5.8345  2.3713 2.6759 2.4241 2.1158 2'. 3995  5.3272  0.0286  ±0.3510 6.1247 6.3484 6.8406  7.7200 7.8694  6.98062  ±0.3527  .02708 .02953 .02732 .02760 .03139  1.6095 1.9745 1.7776 1.9246 2.0115  .00666 .00780 .00683 .00895 .00952  0.0079  .00399 .00397  0.0038  .01142  .01103 .01127 .01304 .01308  0.0120  .00413  .00395 .00384 .00465  .00473 0.0043  38 that,  i n the u n f e r t i l i z e d  seeding  has  fact  t h a t the  heaviest  than  those  seeding  largest  therefore  seems a t f i r s t  f o r n u t r i e n t s and  more v i g o r o u s  rates.  However, t h e  seeding  r a t e s has  greenhouse  on  dismissed  (1959)  t o be  limits rate Why than  occurrence  as  as e r r o r .  acre for acre  the  attest. should  the  leaf  In these  The  attributed  dosage response  and  field  grass  and  high the  and  cannot  Patterson  s e e d l i n g weight,  a r e a were g r e a t e r a t  l b s . per  acre  stands  a c t u a l l y be  d a y s , may  factors.  seedings  easy.  account  has for  100  l b . per  o c c u r r e d may  account  s e e d l i n g s at the of the  seeding  smaller  that root competition  has  be  o b s e r v a t i o n i s not  s e e d l i n g s a t the  small size  heavy  seedlings at  K i t t o c k and  e x p e r i m e n t s a t 36  to other  seeding  400  v i g o r of the  the  and  from the  that root competition  But  minimal  a t low  It  rates  However, t h e r e must  fact  of the  produced  a t low.  seedlings i n thin stands?  be  (Frederick, Brink)  e x p l a n a t i o n f o r the  smaller size  rate.  must be  low  seeding  i n the  individual  and  r a t e s than  An  comparative  the  both  Furthermore,  observations  in thick  rate;  of•larger  been o b s e r v e d  a l s o r e p o r t t h a t the  occurred, the  high  anomalous.  w a t e r w o u l d be  several occasions  seeding  low  seedlings develop  root penetration, height heavier  a t the  seedlings should  f r e q u e n t l y been assumed t h a t a t t h e  competition  be  s e e d l i n g s a t the  rate.  The the  the  r a t e were somewhat l a r g e r  seedling  at  soils,  thin  4-00  stand  l b . per seedlings  Perhaps t h e r e  modify the  soil  is a  not  39  environment  to their  the  environment  surface  extremes Certainly  of temperature  Maybe h e r e i n  a s h a s been  established. soil quite  lies  stands i s subject  alter  small  the surface  temperature  r e s p o n s e s might  that  regime.  o f t h e companion  suggested but not  m o i s t u r e was n o t l i m i t i n g  affected.  differences i n seedling  one o f t h e c h i e f v a l u e s so o f t e n  Perhaps  to greater  and s e e d l i n g s a r e a d v e r s e l y  I t i s recognised  different  through e x c r e t i o n s .  i n thin  i t i s known t h a t  density profoundly  crop  advantages  experimentally  i n these experiments  and, as h a s been obtain  suggested,  i f i t were.  e> 3 5 3  30  UJ  20 *  15  £  10  UJ  £  5  r I  TOIL  TOP ROOT  11  R0OT||  f  25  PER  TOP ROOT ACRE  RATES  PER  FERTILIZED  iH  UNFERTILIZED  TOP ROOT  l l  100  K$j  |  TOP  ROOT ACRE  400  ROOT PER  ACRE  OF SEEDING  Fig,11 - Average dry weights of 36 day seedlings of perennial ryegrass from stands established at rates of 2 5 , 100, and 400 pounds per acre.  41 6 -  Project  Seasonal hydrate  a)  i n t h e r o o t s and  may  be  i s limited.  said  that  Good r o o t s a m p l e s f r o m  chemical a n a l y s i s  Attendant of  on  sampling  soil  and  field  be  directed  s u c h as  Moreover,  m i n e r a l and  of f i n e  contamination  organic matter  of r o o t chemical  composition  towards the a n a l y s i s  achieved  much m e a n i n g . branch  roots  of a r o o t  and  dead r o o t s  tend t h e r e f o r e  of gross m a t e r i a l s ,  " r e s e r v e " c a r b o h y d r a t e s , which emphasize  a storage organ.  As  literature  t h e r e a r e a number o f s u c h  Without  review  doubt the  has  has  their  chemical nature  the r o o t  as  p r e v i o u s l y been d i s c u s s e d i n the  importance  roots  for  grown p l a n t s  the u s u a l p r e c i s i o n  i s always a l o s s  of  likely. Studies  to  carbo-  of b a r l e y .  i s therefore often without  unknown m a g n i t u d e .  sample, w i t h is  tops  reserve  t h e knowledge o f t h e c h e m i s t r y  are obtained w i t h d i f f i c u l t y in  and  Object It  roots  trends i n l i g n i n  studies.  of r e s e r v e carbohydrates  been d e l i n e a t e d , d e s p i t e d i f f i c u l t i e s and  i n d e c i d i n g on  in  in defining  suitable  methods  analysis. It  has  carbohydrates  sometimes been assumed t h a t and  i n roots  structural  a s s o c i a t e d m a t e r i a l s s u c h as l i g n i n  as f r e e l y  e l a b o r a t e d as  Troughton  (1957)  i n aerial plant  p o i n t s out,  parts.  are  However,  i n grasses there i s  little  evidence  f o r t h i s p o i n t o f v i e w and c o m p a r a t i v e l y  little  chemical  s t u d y i n any  event  has  been  undertaken.  not as  42 It the  a p p e a r e d t o be  gross  this  chemistry  was  of the  decided  reserve deal of  of the  roots  to d i r e c t  and  t o e x t e n d knowledge  of annual grasses serial parts  and  effort  towards the  and  analysis  to l i g n i n ,  really  gross It  of good a  s u b s t a n c e s , w h i c h a r e presumed t o d e c a y s l o w l y  complex in  soil.  Methods The  studied  by  barley roots  and  t o p s were f r o m t h e  Lindahl  the  L i g n i n was  (1948);  et_ aJL.  the  plants  R e s e r v e c a r b o h y d r a t e s were  a method d e v e l o p e d by Weinman  d e t e r m i n e d by by  4.  in Project  mined by fied  of  relate  grasses.  c a r b o h y d r a t e s w h i c h have been a c c o r d e d a and  to  t o the  tops of p e r e n n i a l  of a t t e n t i o n i n r o o t s  b)  not  of r o o t s  to t h e , a n a l y s i s  chemistry  worthwhile  sugars,  method p r o p o s e d  by  p r o c e d u r e recommended by d e t e r m i n e d by  the  a n a l y t i c a l procedures are  and  modi-  however, were  (1945)  Somogyi Lindahl  A.O.A.C.  given  (1946)  deter-  et_ al_.  (i960)  and (ibid.).  method.  i n some d e t a i l  in  The  the  appendix. c)  O b s e r v a t i o n s and The  despite  method f o r r e s e r v e  a good d e a l  satisfactory, difficulty respectable "short"  discussion  left  of e f f o r t much t o be  remain u n c e r t a i n . results  methods  and  (e.g.  carbohydrate spent  i s t o be  the  in trying  desired; The  determination,  the  t o make i t  causes  of  method f o r l i g n i n preferred  "Arizona"  to  gave  several  method) w h i c h were  43 also  tried. The  12, 13,  Figures  The be  results  root  i n carbohydrate  dry matter,  reserve  follow  matures,  a p a t t e r n which  g r a s s s u c h as b a r l e y ,  relatively  reserve  plants  more r e s e r v e c a r b o h y d r a t e i s  p o r t i o n s of the p l a n t .  than  in non-fertilized  carbohydrate remains  season's  of the t o t a l  m a t u r e s and, c o n v e r s e l y ,  Slightly  c a r b o h y d r a t e was e l a b o r a t e d i n b o t h r o o t  fertilized  might  v i z . a marked  r e s e r v e s , as a p e r c e n t a g e  o c c u r s as the p l a n t  i n the a e r i a l  and i n  14.  and  i n an a n n u a l  as t h e p l a n t found  a r e g i v e n i n T a b l e 2,  reserve carbohydrates  expected  decline  of a n a l y s i s  plants.  more  and t o p I n Very  i n the roots of barley  little  by  end.  Lignin  c o n t e n t , as one m i g h t  barley,  increases percentagewise,  content  drops.  expect,  i n the r o o t s of  as t h e " r e s e r v e " c a r b o h y d r a t e  On t h e o t h e r hand, a s r e s e r v e  percentage  rises  i n the a e r i a l  percentage  remains  about  part  carbohydrate  of the p l a n t  even o r drops  slightly.  the l i g n i n  TABLE 2  44  BASIC GRAVIMETRIC DATA AND CHEMICAL ANALYSES FOR BARLEY  Stage  Wt.  Gm.  Top  Ratio  Root  •  %  Average % available carbohydrate s  Lignin  T/R  Top  Root  2.968 2.742  NonFert. 6" June 16/61  1.028 1.069 1.223 1.204  0.844 1.067 1.036 1.018  1.216 1.001 1.180 1.182  2.544 2.544  12.60 no more sample  Av.  1.131+0.048  0.991+0.050  1.140  2.699+0.100  12.60  Fert. 6"  2.128 2.483 2.020 2.280  1.361 1.384 1.050 1.111  1.563 1.794 1.923 2.052  1.629 1.820 1.821 1.665  12.22 12.18 13.90 10.02  2.228+0.100  1.226+0.085  1.816  1.734+0.050  12.080+0.795  NonFert. 10" June 23/61  4.304 3.473 3.679 3.668  2.089 2.080 2.054 1.710  2.060 1.669 1.791 2.144  3.007 2.654 2.565 2.530  Av.  3.781+0.181  1.983+0.091  1.906  2.689+0.109  12.892+0.112  3.038  2.032  3.510  2.253  12.697  3.774 2.759 3.002 4.307  3.429 2.948  2.141 2.167  11.80 11.62 11.71 11.19  11.036+0.666  3,460+0.355  3.189  2.148+0.044  11.58+0.135  4.499 4.321 4.979 4.947  6.330 6.723 4.323 5.406  15.27 13.65 13.95 10.94  4.677  5.695+0.534  13.452+0.908  Fert. 10"  11.468 9.684  10.294 Av. NonFert. 30" Blooming July 14 Av.  31.001 44.552 41.724 45.592 40.717+3.340  6.890 10.309 8.380 9.214 8.705+0.721  Top  Root  3.40  5.62  2.25  4.58  1.87  4.18  1.47  4.17  8.56  1.36  12.68  12.72 13.05  13.12  6%  45  TABLE 2 cont'd.  Stage  Wt. Gm.  Average % available carbohydrates  Ratio  %  4.499 4.321 4.979 4.947  6.330 6.723 4.323 5.406  15.27 13.65 13.95 10.94  4.677  5.695+0.908  13.452+0.908  5.413 5.872  11.14 11.24 12.57 13.68 12.157+0.603  Lignin  NonFert. 30"  Blooming July 14/61  31.001 44.552 41.724 45.592  Av.  40.717+3.340  Fert. 115.175 30"  125.339 Bloom- 104.648 ing 120.604  Av. MonFert. Maturing Aug.  116.442+4.445  5/61  57.390 74.445 77.575 77.068  Av.  71.619+4.792  Fert. 187.515 Matur- 191.085 ing 142.515 Av. NonFert. Late Sept.  6.890 10.309 8.380 9.214 8.705+0.721 21.275 21.344 17.609 14.462  8.339  6.861 6.226 6.981 5.323  18.673+1.652  6.236  6.438+0.380  7.120 8.950 11.405 11.730  8.060 8.317  9.801+1.037  5.942  —  6.570  6.674 6.403 8.664  13.43 13.39 11.45 12.40  7.307  6.538+0.713  12.667+0.470  6.301  194.725  23.135 24.030 13.090 20.560  8.087 7.951 7.378 9.471  178.960+12.24  21.466+1.365  8.337  8.590 10.480 8.370 6.845  8.56  1.36  9.60  1.57  10.56  2.25  12.64  4.76  11.55  1.34  14.73  1.98  10.84 10.88 7.62 12.23  8.571+0.745  10.392+0.979  49.500 54.94 59.38  4.740 5.710 4.730  10.443 9.621 12.553  7.780 8.307 8.201  17.72 17.02 18.25  54.606+2.357  5.060+0.325  10.791  8.196+0.159  18.133+0.356  18  Av.  Fert. 143.120 Late 159.510  11.480  12.466  8.904  17.29  11.380  14.016  6.381  17.95  140.210  13.420  10.477  8.377  14.04  141.580+6.007  12.093+0.664  11.707  8.054+0.606  16.36+1.208  Av.  SAMPLING  • 12 -  DATES  The seasonal change i n available carbohydrate percentage of fertilized and unfertilized barley plants.  Fig. 13 - The seasonal change i n lignin percentage of f e r t i l i z e d and unfertilized barley plants.  48  SAMPLING  DATES  . .  Fig. 14 -  Logarithm plus one of dry matter i n grams, of top and root per box of fertilized and unfertilized barley plants.  i  49 Project  7 - Seasonal in  Object  orchard  grass  orchard  lignin  f o r d r y matter  study  o f t h e b a r l e y and o r c h a r d  to include reserve  grass  grass  tops  and r o o t s  by t h r e e  a d o p t e d were t h o s e Although  to a single  of seeding,  s e a s o n and t o t h e y e a r  nature  do n o t c o m p l i c a t e  over  some e a r l i e r  with p e r e n n i a l grasses  study  t h a t t h e low l i g n i n  t h a t i t w o u l d be i n o r d e r  fields W  e  l l  a  s  environment  of t h i s  only,  relate  some  analytical  studies  i n t h a t dead  "Latar"  to  of t h i s  (Sosulski  roots  orchard  variety  i960).  t o determine  It  lignin  v a r i e t y produced under the  of the U n i v e r s i t y of B r i t i s h  and a l s o t o d e t e r m i n e forage.  the r e s u l t s  i n that  forage  20$  was f e l t  i n the forage  by  18  digestibility  maritime  already  i n h e r e n t l y low i n l i g n i n .  improved  levels  weeks.  a t Washington State U n i v e r s i t y , a t Pullman,  Wash., was r e l e a s e d a s a v a r i e t y I t was c l a i m e d  seemed  the assays.  P o i n t was added t o t h i s developed  Extension  that the p l a n t i n g dates  differed  t h e methods f i n a l l y  a d v a n t a g e may be c l a i m e d  elaborated  carbohydrate  given under P r o j e c t 6 f o r b a r l e y .  grass  stands of  g r a s s , b a r l e y , and a p e r e n n i a l  t o be d e s i r a b l e t h o u g h i t i s r e a l i z e d  of a s i m i l a r  carbohydrate  varieties.  a n a l y s i s of the orchard  Essentially  year  g r a s s , were g i v e n u n d e r P r o j e c t 4.  of the comparative and  of a f i r s t  g r a v i m e t r i c data  t o p a n d r o o t o f an a n n u a l  grass,  and r e s e r v e  and Methods  Comparative in  in lignin  t h e r o o t s and t o p s  three  c)  trends  the l i g n i n  levels  Columbia  i n r o o t s as  50  b) O b s e r v a t i o n s The and  trends  of l i g n i n  varieties  ( p l e a s e see T a b l e i n the percentages  i n tops  place reserve  percentage-wise  of reserve  of the annual  carbohydrates  rather slowly at f i r s t  tend  barley.  t o accumulate  accumulation  by c o n t r a s t as t h e season advanced  grass reserves disappeared  from the r o o t .  i n the annual  I t i s probably  u n w i s e t o p l a c e much e m p h a s i s on t h e i n t e r - v a r i e t a l shown i n F i g s . lity  quite root  lignin  and 17, b e c a u s e  determinations  satisfactory lignin,  "tops"  is  16,  to f a l l  I f there  or r i s e  n o t v e r y marked.  support lower  than  i s consistently higher  or r o o t s of orchard  Furthermore,  the contention that  in lignin  b y t h e A.O.A.C. method were  i s a tendency f o r the l i g n i n  i n the tops  other  instabi-  determination.  and show c o n s i s t e n t i n t e r - v a r i e t a l  i t i s t o be n o t e d ,  lignin.  differences  of the s i n g u l a r  o f the c o l o u r development i n the chemical The  age  15,  grass  i n the p e r e n n i a l  g r a s s r o o t s , b u t as t h e season advances t h i s accelerates;  carbohydrate  and r o o t s o f t h e p e r e n n i a l o r c h a r d  d i f f e r markedly from those  In t h e f i r s t  3 and F i g u r e s ) .  there  is little  "Latar" orchard varieties.  grass  patterns; than percent-  grass i t  evidence t o i s inherently  TABLE 3  51  GRAVIMETRIC DATA AND CHEMICAL ANALYSIS FOR THE ORCHARD GRASS VARIETIES (Grasses Planted July 14, 1961)  Ratio  Wt. Gm.  Top  Root  T/R  %  Average % available carbohydrates  Lignin  Top  Top  Root  14.545+0.326 2.80  1.30  Root  July 22/61 LATAR  16.460 21.642 25.762 18.432  12.434 12.819 14.027 10.977  1.324 1.688 1.837 1.680  Av.  20.574+2.036  12.564+0.628  1.632  13.297  16.007 15.416 13.185  1.504 1.551 1.993 1.347  DANISH 15.883 24.811 30.742 20.750  11.000 8.713 8.662 9.523 9.476+0.545 10.980 7.058 8.224 8.063  15.10 14.28 14.17 14.68 14.557+0.211 3.94  Av.  23.046+3.148  14.477+0.724  1.591  S-143  13.064 12.715 12.046 15.277  11.220 10.599 9.169 11.619  1.163 1.199 1.313 1.314  Av.  13.276+6.999  10.652+0.537  1.247  9.107+0.969  14.597+0.468 1.25  Aug. 5/61 2nd Harv. 10" 27.310 LATAR 28.680 30.015 28.530  16.200 18.365 18.385 20.350  1.717 1.571 1.632 1.402  9.103 7.916 8.250 9.610  13.16 12.64 12.79 12.96  Av.  18.325+0.847  1.570  8.721+0.389  12.837+0.112 3.54  DANISH 39.390 38.735 38.330 36.450  25.500 24.935 26.450 25.980  1.545 1.553 1.449 1.403  Av.  35.726+0.631  25.716+0.322  1.389  9.909+0.234 14.682+0.234 1.75  1.06  S-143  43.065 49.198 34.592 30.095 39.237+4.271  21.470 22.210 22.580 23.900 22.540+0.508  2.005 2.215 1.532 1.259 1.740  9.226 9.734 8.602 9.307 9.232+0.233  1.69  Av.  28.759+0.460  8.581+0.840  14.47 14.00 14.23 15.48  11.690 7.643 7.612 9.482  9.371 10.100 9.714 10.450  4.43  15.94 14.14 13.82 14.49 1.42  1.87  14.09 15.19 14.55 14.86  14.57 13.03 14.24 14.34 14.045+0.345 3.85  TABLE 3 - cont'd.  Wt.  Gm.  Top  Ratio  Root  %  52  Average % available carbohydrates  Lignin  T/R  Top  Root  9.995 11.82 9.237 9.406  15.74 15.30 12.33 12.30  Top  Root  Aug. 3/61  Har. LATAR 53.890  3rd  45.150  52.270  40.880 43.120  1.193 1.277 1.267 1.213  Av.  53.202+0.708  43.017+0.872  1.237  10.114+0.594  13.917+1.056  DANISH  76.900 71.570 59.800  58.800 62.000 59.370 57.000  1.308 1.311 1.205 1.049  8.194 10.02 10.28 8.764  13.49 12.44 12.37  Av.  72.380+4.637  59.292+1.034  1.220  9.314+0.499  12.755+0.259  S-143  75.090 75.250 68.800 69.430  49.50 54.00 64.00 50.00  1.517 1.393 1.075 1.240  3.303 7.567 9.430 9.258  14.08 13.55 14.03 13.37  Av.  72.142+1.753  58.75+3.362  1.227  8.639+0.435  13.757+0.176  1.168 1.116  4.768 4 . 5 2 4  1.594 1.102  5.052  13.15 12.91 13.59 13.68  1.222  4.781+0.152  13.332+0.182  1.151 1.629 1.120 1.479  4.837  13.24  4.956 5.599  12.96 13.89 13.87  37.728+10.210  1.313  5.127+0.236  13.485+0.232 14.86  129.51  72.30 91.10 56.60 86.70  1.744 1.452 2.230 1.493  5.563 4.926 5.313 6.151  14.04 14.29 14.58 15.28  128.555+1.475  76.675+7.803  1.676  5.513+0.256  14.547+0.268 14.80  54.850 51.800  81.250  4 2 . 9 2 0  3.08  1 . 9 2  8.19  5.33  7.32  3.22  12.72  Sept. 26/61 4 t h Har. Late i n 85.80  season  94.90  LATAR  86.90  73.45 83.05 59.5 78.80  Av.  90.075+2.208  73.70+5.125  the  DANISH  92.70  126.64 134.58 107.78 91.90  Av.  115.225+9.594  S-L43  1 2 6 . 1 6  132.31 126.24  Av.  110.06 82.6 96.15 62.10  14.89  13.25  10.00  7.24  53  Fig, 15 -  The seasonal change i n carbohydrate percentage of Latar orchard grass, top and root.  Eig. 16 - The seasonal change i n carbohydrate percentage of S - 1 4 3 orchard grass, top and root.  55  Fig, 17 - The seasonal change i n carbohydrate percentage of Danish orchard g rass, top and root.  Fig  #  IB -  The seasonal change i n lignin percentage of Latar orchard grass, top and root.  15  .  10  S-143 —  ORCHARD  GRASS  ROOT  TOP  C5  5  .  SAMPLING  Fig.  DATES  19 - Seasonal change i n lignin percentage of S-143 orchard grass, top and root  DANISH  ORCHARD  SAMPLING  . 20 -  GRASS  DATES  Seasonal change i n lignin percentage of Danish orchard grass, top and root.  59 General D i s c u s s i o n and Summary That r o o t s , t h e i r morphology, p h y s i o l o g y and c h e m i s t r y , a r e d i f f i c u l t t o study i s g e n e r a l l y conceded. In s i t u o f t e n they cannot be seen and hence many r o o t phenomena must be s t u d i e d by i n d i r e c t means.  Roots d i e and  decay s l o w l y , and f r e q u e n t l y i t i s d i f f i c u l t t o d i s t i n g u i s h living  f r o m dead r o o t s .  Very often too r o o t s are separated  from t h e i r s o i l environment o n l y t h r o u g h p a i n s t a k i n g e f f o r t and these o n l y i n c o m p l e t e l y .  N o n e t h e l e s s i t s u r e l y can be  s a i d t h a t p l a n t ^ s t u d y w i t h o u t r o o t study i s i n c o m p l e t e  and  t h a t , hard though i t may be t o g a i n , knowledge of r o o t s s h o u l d be v i g o r o u s l y sought a f t e r .  I t may be added t h a t i n  no f i e l d i s r o o t study more i m p o r t a n t  than I n f o r a g e  crops,  where i t i s r e a l l y the p e r e n n i a l r o o t and crown system w h i c h c o n f e r s i n t h e crop any g a i n i n d r y m a t t e r p r o d u c t i o n i t may make over annual a r a b l e crops such as c e r e a l s and r o o t s . The p r o j e c t s a f o r e m e n t i o n e d p r o v i d e d an o p p o r t u n i t y t o examine t e c h n i q u e s w h i c h a r e c l a i m e d t o be o r promise t o be u s e f u l i n r o o t s t u d y .  I t i s g r e a t l y t o be r e g r e t t e d  t h a t l a n d tenure p o l i c y d i d not p e r m i t the use of r a d i o t r a c e r s w i t h emanations more e n e r g e t i c than those g i v e n by P^gj p o s s i b l y t h e t h i n w a f e r t e c h n i q u e  c o u l d be so used t h a t  X - r a y photos of growing r o o t s c o u l d be taken and so a v o i d the h a z a r d s a t t e n d a n t iodine.  i n t h e use of such t r a c e r s as r a d i o -  I n any event t h e " t h i n w a f e r t e c h n i q u e "  appears t o  produce f a i r l y normal r o o t s and the c o n d i t i o n s a t the s o i l g l a s s i n t e r f a c e do not appear t o he h i g h l y abnormal f o r r o o t growth.  U s i n g t h i n w a f e r s i t seems p o s s i b l e t h a t a c a r e f u l l y  p l a n n e d s t a t i s t i c a l approach c o u l d be made t o the a c t i o n s w h i c h may  inter-  e x i s t between r o o t s of g r a s s e s and  when grown i n a s s o c i a t i o n .  One  legumes  handicap remains, v i z . no  easy method f o r the d i s t i n c t i o n of g r a s s and legume r o o t s has been d e v e l o p e d . Sprague and h i s ^ a s s o c i a t e s (1962) have r e f e r r e d v e r y r e c e n t l y t o some of the p u z z l i n g f e a t u r e s i n f o r a g e  crop  competition.  seedlings  The  observations  i n the p r o j e c t s w i t h  o u t l i n e d e a r l i e r tend t o support  t h e i r contention.  It is  somewhat s u r p r i s i n g , f o r example, t o f i n d t h i n l y e s t a b l i s h e d s e e d l i n g s a c t u a l l y d o i n g l e s s w e l l than s e e d l i n g s i n t h i c k e r stands.  A l s o i t would appear t h a t s o i l volume and r e l a t e d  f a c t o r s must be more c a r e f u l l y taken i n t o account i n s e e d l i n g s t u d i e s , f o r w i t h l i g h t , n u t r i e n t s and water not o t h e r f a c t o r s of s o i l might w e l l become i m p o r t a n t competition.  limiting, factors in  I t seems, f o r example, t o be g e n e r a l l y conceded  that seedlings competition i s e a r l y manifested  long before  t o t a l solum i s e x p l o i t e d and b e f o r e l i g h t and o t h e r f a c t o r s become l i m i t i n g but the p r e c i s e nature of the elements of c o m p e t i t i o n are f a r from c l e a r . The  r o o t and top i n t e r r e l a t i o n s h i p s seen w i t h an  annual g r a s s , b a r l e y and a p e r e n n i a l g r a s s , o r c h a r d  grass,  the  are  much as might he e x p e c t e d .  As F o t h (1962) has r e c e n t l y  observed w i t h a n o t h e r annual c r o p , c o r n , pronounced  changes i n  r a t e o f growth o f b o t h t o p and r o o t o c c u r r e d i n b a r l e y ; t h e weight o f t o p o c c u r r e d more r a p i d l y r e l a t i v e l y than r o o t t o produce a marked i n c r e a s e on t h e t o p / r o o t r a t i o and g r a i n development o c c u r r e d l a r g e l y a f t e r r o o t growth ceased.  The  p e r e n n i a l g r a s s i n i t s f i r s t y e a r from s e e d i n g however, m a i n t a i n e d a f a i r l y u n i f o r m t o p t o r o o t r a t i o and by the end of  t h e growing season had e l a b o r a t e d much more d r y m a t t e r  t h a n had t h e a n n u a l g r a s s . Carbohydrate r e s e r v e s have been s t u d i e d now f o r a number o f f o r a g e crops and d e s p i t e d i f f i c u l t i e s i n t h e development o f s u i t a b l e a s s a y s f o r " r e s e r v e " substances t h e g e n e r a l f e a t u r e s o f t h e i r a c c u m u l a t i o n w i t h season and w i t h management systems i s f a i r l y c l e a r .  The p a t t e r n s f o r o r c h a r d  g r a s s conform r a t h e r w e l l w i t h those t o be expected from o t h e r work'(e.g.  Smith 1962)  i n that accumulation accelerated w i t h  the advance o f the season. for  I t would appear t h a t the p a t t e r n  b a r l e y i s t h a t e x p e c t e d f o r an annual g r a s s but i t i s  a p p a r e n t l y t h e f i r s t r e c o r d o f such. The l i g n i n t r e n d s as e x p r e s s i v e o f t h e s t r u c t u r a l elements o f g r a s s e s a r e not so easy t o u n d e r s t a n d .  The  a n a l y s i s i s c a r r i e d out, a c t u a l l y , w i t h more p r e c i s i o n than t h a t of " r e s e r v e " c a r b o h y d r a t e s but the r o l e o f l i g n i n i s p r o b a b l y n o t so e a s i l y d e f i n e d .  I t i s , probably, s i g n i f i c a n t  62  that  the l i g n i n i n the r o o t s of the annual  increase with maturity and'is, probably, degradation "attacked" of  It  indicative  by t h e s o i l  f l o r a and f a u n a .  i s somewhat u n e x p e c t e d i s clear  inadequacies  from  The r e l a t i v e  to increasing  crops.  constancy  on a_ p r i o r i g r o u n d s .  the f o r e g o i n g s t u d i e s t h a t d e s p i t e  i n technique  of forage  easily  carbohydrate  that worthwhile  c o n t r i b u t i o n s can  be made t o t h e knowledge o f t h e b i o l o g y and c h e m i s t r y roots  to  of the  o f components o f dead o r d y i n g r o o t s more  t h e l i g n i n component r e l a t i v e  reserves  grass tended  of the  63  APPENDIX  64 A.  METHOD USED FOR THE DETERMINATION OF *RESERVE» HYDRATES  (AFTER LINDAHL  CARBO-  (194871  Procedure W e i g h o u t a 0 . 1 - t o 1- gram sample transfer  t o 125-ml. e r l e n m e y e r  been w e i g h e d a c c u r a t e l y of  distilled  water  water  into  has p r e v i o u s l y  t o t h e n e a r e s t 0.01 gram.  and h e a t  - bath to gelatinize  funnel  f l a s k which  o f m a t e r i a l and  f o r o n e - h a l f hour starch,  Inserting  the neck o f the f l a s k t o minimize  Add 10 m l .  on a b o i l i n g a small glass the l o s s of  water.  C o o l t o room t e m p e r a t u r e ,  outside  o f t h e f l a s k and t h e i n s i d e  paper.  P l a c e t h e f l a s k on t h e b a l a n c e , and b y means o f a  dropper  add a s many d r o p s  replace  the water  lost  wipe t h e m o i s t u r e f r o m t h e o f i t s neck w i t h a  of d i s t i l l e d  by e v a p o r a t i o n .  u s e d must e q u a l t h e w e i g h t  water  filter  as n e c e s s a r y t o  The c o u n t e r p o i s e t o be  of the f l a s k p l u s the weight of  the  sample p l u s 10 grams.  (pH  4.45J p r e p a r e d b y m i x i n g t h r e e volume p a r t s o f 0 . 2 N  acetic  f l a s k thus 30 m l .  solution  acetate  10 m l . o f c l a r a s e ( 0 . 5 $ ) s o l u t i o n i n t o t h e  increasing  Stopper  stopper,  10 m l . o f b u f f e r  o f 0 . 2 N sodium  a c i d w i t h two volume p a r t s  s o l u t i o n ) and  flask  Pipette  the l i q u i d  volume o f t h e d i g e s t t o  the f l a s k t i g h t l y w i t h a w e l l - f i t t i n g  and i n c u b a t e f o r 44 h o u r s  rubber  a t 37° C., s h a k i n g t h e  occasionally. C o o l t o room t e m p e r a t u r e ,  neutral  lead  a c e t a t e , shake,  a d d 50 t o 100 mg. o f powdered  and a l l o w p r e c i p i t a t e  and r e s i d u e  65 to  settle.  T e s t f o r completeness of the r e a c t i o n w i t h a s i n g l e  drop o f d i l u t e p o t a s s i u m o x a l a t e s o l u t i o n and f i l t e r , w i t h o u t washing, t h r o u g h a d r y h i g h l y r e t e n t i v e f i l t e r (Whatman No. 42)  paper  i n t o a d r y f l a s k c o n t a i n i n g 100 t o 200 mg. o f  powdered p o t a s s i u m o x a l a t e .  Shake, t e s t f o r completeness of  d e l e a d i n g w i t h a drop o f d i l u t e l e a d a c e t a t e s o l u t i o n , s t o p p e r , and l e t s t a n d from t h r e e t o f o u r h o u r s , or o v e r n i g h t i n a refrigerator. F i l t e r and h y d r o l y z e a 15 m l . a l i q u o t w i t h 0.75 m l . of 25$ h y d r o c h l o r i c a c i d f o r one h a l f hour on the b o i l i n g water b a t h , a t t a c h i n g t h e f l a s k t o a r e f l u x condenser.  Cool, transfer  q u a n t i t a t i v e l y t o a 50-ml. s t a n d a r d f l a s k , n e a r l y n e u t r a l i z e w i t h 25$ sodium hydroxide- s o l u t i o n ( u s i n g a few drops o f methyl - r e d s o l u t i o n as i n d i c a t o r ) , and make t o volume. The f i n a l e x t r a c t volume (50 ml.) c o n t a i n s 15/30  ( o n e - h a l f ) the  t o t a l a v a i l a b l e c a r b o h y d r a t e of t h e o r i g i n a l  digest.  Sugar d e t e r m i n a t i o n Reagent:  1 liter  o f t h e s o l u t i o n c o n t a i n s 28 gm. o f  anhydrous d i s o d i u m phosphate, 100 ml. g. normal  sodium  h y d r o x i d e , 40 gm. g. sodium p o t a s s i u m t a r t r a t e s a l t , 8 gm. of  c u p r i c s u l f a t e ( c r y s t a l l i n e ) , and 180 gm. o f anhydrous  sodium s u l f a t e .  The s o l u t i o n i s p r e p a r e d i n t h i s way.  The  phosphate and t a r t r a t e a r e d i s s o l v e d i n 'about 700 m l . of w a t e r , the of  sodium h y d r o x i d e i s added, and t h e n , w i t h s t i r r i n g , 80 m l . a 10$ copper s u l f a t e s o l u t i o n a r e i n t r o d u c e d .  F i n a l l y the  66  sodium  sulfate  to 1 liter  diluted  which time the  i s added a n d , when d i s s o l v e d ,  good g r a d e  of f i l t e r  determination.  and t h e remainder  paper.  with a glass  5 c.c. of the reagent i n a 30 x 200 mm.  funnel,  and h e a t e d  iodide  (2|-$ s o l u t i o n )  down t h e w a l l  agitation. sulfuric  acid  so t h a t  acidified  0.1N  a t once.  as  from  f o r the p l a n t  "total  available  Blank new c l a r a s e  i s used  i nthe  Pyrex  test-tube,  After  covered  i n a vigorous  cooling,  6 ml.  1.5  without  s t i r r i n g or  ml. of approximately  i s rapidly  the test-tube,  dropped,  with  from time  rather  simultaneous  c o n t e n t s of t h e tube  For t i t r a t i o n  2.ON  a r e mixed  0.05N t h i o s u l f a t e d i s  t o time  by d i l u t i o n  from  solution.  Subtract value  about  the e n t i r e  This i s prepared stock  indefinitely  i s added b y r u n n i n g i t f r o m a  a r e added; t h e a c i d  than p e r m i t t e d t o flow i n t o  used.  through a  and 5 c . c . o f t h e e x t r a c t  of the test-tube,  Following this,  agitation,  keeps  by immersion  water bath f o r t e n minutes.  pipette  and  This reagent  top part of  filtered  The i o d e m e t r i c t e c h n i q u e  a r e mixed  potassium  The c l e a r  of d e t e r i o r a t i o n .  Technique:  boiling  separate out.  i s decanted  w i t h no s i g n  solution  a n d a l l o w t o s t a n d f o r a day o r two, d u r i n g  impurities  solution  the s o l u t i o n i s  the blank t i t r a t i o n digest,  calculate  value the t i t r a t i o n  a s g l u c o s e , and r e p o r t  carbohydrate".  d e t e r m i n a t i o n s s h o u l d be c a r r i e d  o u t whenever t h e  ( t r a d e name o f t a k a d i a s t a s e ) s o l u t i o n  i s used.  67 For t h i s buffer  p i p e t t e 10 m l . o f d i s t i l l e d  purpose,  solution,  and 10 m l . o f t h e c l a r a s e  100-ml. e r l e n m e y e r the  blank  Incubate,  solution  (except  omitted  i n t h e case  glucose  and s u b s e q u e n t l y  f o r the g e l a t i n i z a t i o n of the b l a n k s ) .  i s used.  Procedure  B.  treatment  plug with  determination.  lined with  replace with ether  ( l + 2)  f o r four hours.  Replace the  allowing the Soxhlet  to f i l l  t w i c e and  ( t h e h o t - p l a t e must be c o o l e d down b e f o r e  t h e e t h e r on) f o r o n e - h a l f h o u r .  C. i n t h e oven f o r one h o u r ,  100 m l . w i d e - m o u t h e r l e n m e y e r . i n 0.1N H c l , w e t t i n g  Dry the thimble a t  and t r a n s f e r  Add 40 m l . ifo  sample t o a solution of  sample w e l l b y a d d i n g  of the s o l u t i o n ,  finally  w a s h i n g down t h e s i d e s o f f l a s k s w i t h r e m a i n d e r Incubate  Add  a t 40°C.  or shaking  asbestos  t h o r o u g h l y and of  overnight.  20 - 30 m l . h o t w a t e r and f i l t e r  crucible with a thin Transfer  stirring  a small  portion  solution.  filter  c o t t o n w o o l and p l a c e i n t h e S o x h l e t . E x t r a c t  extractor with alcohol,  pepsin  40 mg.  METHOD USED FOR THE DETERMINATION OF LIGNIN  with alcohol-benzene  130°  which i s  f o r the standard  of blank  W e i g h 1 gm. o f sample i n t h e t h i m b l e  placing  treat  For the standard,  and t r e a t m e n t  a r e e x a c t l y t h e same a s i n t h e c a s e  paper,  into a  d i g e s t i n e x a c t l y t h e same way a s t h e o t h e r  digests  of  flask.  10 m l . o f  water,  layer,  through  wash w i t h  gooch  water.  t o a 600 m l . b e a k e r w i t h 150 m l . 5$ HgSO^.  Reflux  68  vigorously to  maintain  with a thin ml.  on h o t p l a t e  f o r 1 hour,  original  volume.  asbestos  layer.  portions ether.  adding  Filter  through  D r y i n oven a t 1 3 0 ° C .  hours,  filter  paper  u s i n g 150 m l . 3 $ RgSO^.  and r e f l u x Filter  1 0 5 - 1 1 0 ° C. and d e t e r m i n e  ignition  lignin  a s b e f o r e f o r two  r e s i d u e onto free  by l o s s  gooch w i t h  of acid.  i n weight  Dry on  a t 6 0 0 ° C.  Preparation  o f Sample  Samples a r e o v e n - d r i e d and g r o u n d through  stirring  wash w i t h w a t e r .  a s b e s t o s p a d a n d wash w i t h h o t w a t e r u n t i l at  crucible  (+ 1 5 m i n u t e s ) .  at 20°C,  Add 1 2 5 m l . HgO, f i l t e r ,  Wash r e s i d u e f r o m  gooch  Add 20 m l . 7 2 $ HgSO^  2 0 ° C . t o r e s i d u e a n d h o l d two h o u r s  occasionally.  occasionally  Wash r e s i d u e w i t h t h r e e 20 - 30  T r a n s f e r r e s i d u e t o 200 m l . b e a k e r . at  E^O  a 40 - mesh s c r e e n .  containers u n t i l  ready  i n a Wiley  Samples a r e k e p t  f o r use.  mill  in air-tight  69  LITERATURE  1.'  A.  0.  A.  C.  CITED  O f f i c i a l methods o f a n a l y s i s o f t h e A s s o c i a t i o n of O f f i c i a l A g r i c u l t u r a l Chemists. 9th E d . (i960). 91.92.  2.  A b e r g , E . , I . J . J o h n s o n and C. P. W i l s i e (1943). A s s o c i a t i o n s between s p e c i e s o f g r a s s e s and l e g u m e s . J . Amer. S o c . A g r o n . 35* 357-69.  3.  Ahlgren,  4.  B a k e r , H. 1955.  5.  B o g g i e , R., 1958.  6.  B o g g i e , R. & K n i g h t , A. H. i960. S t u d i e s of r o o t development i n a sward g r o w i n g on deep p e a t u s i n g active tracers. B r i t . Grassland  H. L . and 0. S. Aamodt ( 1 9 3 9 ) . H a r m f u l r o o t i n t e r a c t i o n s as a p o s s i b l e e x p l a n a t i o n f o r e f f e c t s n o t e d between v a r i o u s s p e c i e s o f g r a s s e s and l e g u m e s . J . Amer. S o c . A g r o n . 3 1 : 982-5. K. The e f f e c t o f c u t t i n g on t h e r o o t d e v e l o p ment and h e r b a g e p r o d u c t i o n o f D o l i u m perenne. Ph.D. T h e s i s , U n i v . Durham, Durham, E n g l a n d . H u n t e r , R. P., and K n i g h t , A. H. 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