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UBC Theses and Dissertations

Transpiration and stomatal movements of plants treated with sulphur dioxide Dill, Charlotte Elva 1939

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TRANSPIRATION AND STOMATAL MOVEMENTS OP PLANTS TREATED WITH SULPHUR DIOXIDE  by  Charlotte Siva  A Thesis submitted  Dill  f o r t h e Degree o f  MASTER OF ARTS i n t h e Department of BOTANY  The U n i v e r s i t y o f B r i t i s h C o l u m b i a April,  1939  AGKFOWLEDQ'BIffl¥TS » To Dr. A.H.  Hutchinson I am v e r y g r a t e f u l f o r h i s  a s s i s t a n c e i n t h i s work, f o r h i s a d v i c e i n the i n t e r p r e t a t i o of r e s u l t s , and f o r the use of the equipment necessary. To Dr. P. D i c k s o n I w i s h to express my a p p r e c i a t i o n f o r h e l p and a d v i c e i n growing  the p l a n t s and  setting  up the apparatus and f o r s u g g e s t i o n s of r e f e r e n c e s and methods of o b t a i n i n g d a t a . To the f o l l o w i n g I am a l s o d e e p l y i n d e b t e d . To Mrs. M i l e s R i t c h i e , who  was  o r i g i n a l l y to have  shared i n t h i s workj, f o r c o o p e r a t i o n i n s e t t i n g up the experiment  and making the f i r s t  first  weighings.  To Dr. D i c k s o n and Mr. J.D. Menzies f o r b r i n g i n g s o i l from the greenhouse. To the' Agronomy Department f o r seeds. To the Chemistry Department f o r the use of a wet t e s t meter. To Mr. A. L i g h t h a l l of the C i v i l E n g i n e e r i n g Department f o r the use of a p l a n i m e t e r .  TABLE OF CONTENTS.  A c knowiedg erne n t s. S t a t e m e n t o f t h e problem................  ..  . 1  Methods. The p l a n t c a b i n e t s a n d method o f s u l p h u r d i o x i d e t r e a t m e n t and analysis...................». « 0  3  The p l a n t s u s e d and methods o f g r o w i n g them ..... .«>. 7 0  Measurement o f l e a f a r e a Barley .  ........... 12  Beans .....p..........©.***..................  13  Examination of atomata. Barley  «> 14  Beans .....................<....».........»..<> 16 Method of t r e a t i n g d a t a  17  Data. P l r s t Experiment:  h i s t o r y , environment r e c o r d s  and appearance o f p l a n t s . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19 Second E x p e r i m e n t s  h i s t o r y , environment  r e c o r d s and a p p e a r a n c e o f p l a n t s . . . . . . . . . . . . . . . . . . . . 20 T h i r d E x p e r i m e n t i history., environment r e c o r d s and appearance o f p l a n t s Eo-urth. E x p e r i m e n t s  and  h i s t o r y , environment  22. records  a p p e a r a n c e o f p l a n t s . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23  Tables and graphs o f t r a n s p i r a t i o n measurements ...» 26 Tables and graph o f a t o m a t a l measurements........... 34  TABLE OF CONTENTS (continued) Discussion  of r e s u l t s  36  Conclusions  41  Summary.  43  Bibliography.  44  TRANSPIRATION  AND S.IOMATAL. MOVEMENTS  TREATED W I T H SULPHUR  OE P L A N T S r DIOXIDE.  STATEMENT OE THE PRO BLEU. The p r o b l e m o f t h e e f f e c t o f s u l p h u r  dioxide  gas on t h e f u n c t i o n s o f p l a n t s h a s been a p p r o a c h e d I n t h i s p a p e r f r o m the. p o i n t o f v i e w o f I t s e f f e c t on t r a n s p i r a t i o n c o r r e l a t e d w i t h the opening and c l o s i n g of the stomata. W h i l e t r a n s p i r a t i o n ^ a s a p h y s i o l o g i c p r o c e s s may or may n o t have any v e r y g r e a t p r i m a r y a plant 5 nevertheless  f u n c t i o n i n the l i f e of  measurements o f t h e amount o f  t r a n s p i r a t i o n c a r r i e d o n by a p l a n t s e r v e  a s one i n d e x o f  a p l a n t *s a c t i v i t y , a n d s e r v e as a n i n d i c a t i o n o f t h e d e g r e e o f a t o B i a t a l opening.. The d e g r e e o f s tornate1 o p e n i n g I s o f a c t u a l s i g n i f i c a n c e i n connection synthesis being  w i t h t h e amount o f p h o t o -  c a r r i e d o n . Maximow and K r a s n o s s e l s k y -  maximovr (.11) h a v e e x p e r i m e n t a l l y t r a n s p i r a t i o n and stomatal  c o r r e l a t e d photosynthesis«,  openings.  There I s c o n s i d e r a b l e  d i s a g r e e m e n t among t h o s e  who have w o r k e d on t h e p r o b l e m o f I n v i s i b l e I n j u r y ing the v a l i d i t y of the theory  that sulphur  d e t r i m e n t a l e f f e c t s o n p l a n t a v/hen p r e s e n t t h a t do n o t c a u s e v i s i b l e i n j u r y . W i e l e r  regard-  d i o x i d e has i n concentrations  (16.) f o u n d t h a t i n  3-10 y e a r o l d p i n e s , s p r u c e a n d c e r t a i n hardwoods t h e  - 2 -  a a s i i a i l a t i o n o f c a r b o n d i o x i d e was  reduced, at  dilutions,  b e l o w t h o s e n e c e s s a r y to d i s c o l o r t h e l e a v e s . However  the  c o n c e n t r a t i o n he m e n t i o n s I s v e r y h i g h , 2 p.p.m.  would  and  r  c a u s e v i s i b l e i n j u r y to s u c h p l a n t s as legumes and On  the o t h e r h a n d , Thomas and H i l l  (15)  grains. working  an. the r e l a t i o n o.f s u l p h u r d i o x i d e i n the a t m o s p h e r e to photosynthesis  and  respiration in alfalfa,  found that  con-  c e n t r a t i o n s , w h i c h p r o d u c e d no v i s i b l e i n j u r y a l s o d i d cause, i n v i s i b l e i n j u r y . The  p a p e r s o f Katz. and  not  Ledingham  a r e n o t a v a i l a b l e but have been quoted by S e t t e r s t r o m  et a l .  (13) to the e f f e c t t h a t t h e i r work s u b s t a n t i a t e s  of  Thomas and  Fill.  Setterstram  made I n v e s t i g a t i o n s on  Zimmerman and  9  that  Crocker  (13)  the e f f e c t of low non-marking  con-  centra.tia.ns o f sulphur- d i o x i d e on t h e y i e l d o f a l f a l f a  and  C r u c i f e r a e when grown i n v a r y i n g c o n d i t i o n s o f m o i s t u r e  and  n u t r i e n t supply.  used  had  no  They f o u n d t h a t t h e low  s i g n i f i c a n t e f f e c t on  the species, of C r u c i f e r a e a s i g n i f i c a n t Increase  s  the y i e l d of e i t h e r a l f a l f a  and  i n one  i n the sulphur' c o n t e n t and  o f the  leaves.  cause of  visible  d i o x i d e h a v e shown t h a t t h e d e g r e e o f  i n j u r y I s dependent upon the c o n c e n t r a t i o n s ^ e x p o s u r e and  the h u m i d i t y  duration  of the a i r ( 6 ) . A c c o r d i n g  of  to  Zimmerman and  Crocker (17) humidity  its  t h e s t o m a t a . They f o u n d t h a t w i l t e d p l a n t s  e f f e c t on  or  experiment they found  I n v e s t i g a t i o n s on t h e n a t u r e i n j u r y by sulphur  concentrations  more r e s i s t a n t t h a n t u r g i d o n e s , and  i s a f a c t o r because  of are  a t t r i b u t e the r e s i s t a n c e  to. t h e f a c t t h a t t h e s t o m a t a a r e c l o s e d . The f a c t t h a t a r e more r e s i s t a n t a t n i g h t  plants  than i n d a y l i g h t supports t h i s  idea. Sulphur d i o x i d e i s believed, to a c t through the stomata i n c a u s i n g v i s i b l e i n j u r y and t h e r e i s a p o s s i b i l i t y t h a t I t . m i g h t a c t upon t h e • g u a r d c e i l s t h u s a f f e c t i n g t h e s I z e o f t h e s t o m a t a . I f t h i s were t r u e i t w o u l d be a n explanation o f the reduced a s s i m i l a t i o n o f carbon  dioxide  s t a t e d to; have been f o u n d by some workers„ I n t h e w o r k o f Y/.E. J a c k (7) l o w n o n - m a r k i n g  concentrations  of sulphur  d i o x i d e w e r e f o u n d t o r e d u c e t h e amount o f t r a n s p i r a t i o n significantly  y  and t h e p r e s e n t e x p e r i m e n t was  undertaken  w i t h a view to c o r r e l a t i n g any r e d u c t i o n i n t r a n s p i r a t i o n , w h i c h might o c c u r , w i t h the s t o m a t a ! openings o f the p l a n t s .  ~4-  METHODS. Tlie p l a n t c a b i n e t s and method o f sulphur d i o x i d e treatment and a n a l y s i s . The p l a n t s were grown I n c a b i n e t s under a r t i f i c i a l l i g h t . The two . c a b i n e t s , one f o r sulphur d i o x i d e  treatment  and one f o r c o n t r o l , a r e I d e n t i c a l . I n c o n s t r u c t i o n except f o r the s u l p h u r d i o x i d e i n l e t and m i x i n g chambers on one. The c a b i n e t s a r e c o n s t r u c t e d a c c o r d i n g to the p l a n o f Davis and Hdagland ( 2 ) , except t h a t the l i g h t s a r e d i r e c t l y above the p l a n t s , a s suggested  by Swain and Johnson ( 1 4 ) , and  t h a t i n the base o f each c a b i n e t i s a water tank f o r t h e purpose o f i n c r e a s i n g the r e l a t i v e h u m i d i t y o f the atmosphere. Each c a b i n e t i s composed o f a base 6 f e e t l o n g by 2. f e e t wide by 2. f e e t h i g h i n which the c u l t u r e j a r s a r e p l a c e d on wooden frames. Above t h i s i s a. glass, w a l l e d  cover  6 f e e t l o n g by 2 f e e t wide by 5 f e e t h i g h which can be r a i s e d and lowered  to a l l o w easy access t o the p l a n t s . When lowered  i t i s f a s t e n e d i n p l a c e and the c a b i n e t s a r e p r a c t i c a l l y a i r t i g h t . The l i g h t s a r e seated i n 52 cm. r e f l e c t o r s w i t h the b u l b c e n t r e s 9 i n c h e s above the c a b i n e t t o p s . The h e i g h t o f the l i g h t s above the l e v e l o f the s o i l i s 5^- f e e t . Owing to the extreme heat produced by the l i g h t s the g l a s s tops a r e k e p t covered w i t h about one h a l f to one i n c h of water to absorb the h e a t . The l i g h t s a r e c o n t r o l l e d by a time s w i t c h . A. continuous  c i r c u l a t i o n o f a i r through the c a b i n e t s i s .  maintained  by two S i r o c c o blowers,  d r i v e n by General E l e c t r i c  motors. The sulphur d i o x i d e was i n t r o d u c e d to the exper;Imental c a b i n e t through a g l a s s tube e n t e r i n g the a i r i n t a k e p i p e . The a i r w i t h the s u l p h u r d i o x i d e then passed through a l a r g e g a l v a n i z e d i r o n box c o n t a i n i n g b a f f l e p l a t e s ?/here the gases were t h o r o u g h l y mixed before e n t e r i n g the p l a n t cabinets. The a i r e n t e r s the p l a n t c a b i n e t s a t the bottom, i s d i v e r t e d by b a f f l e p l a t e s i n the base and passes up through the wooden frames s u p p o r t i n g  the p l a n t j a r s . The a i r  passes out through a pipe a t the t o p . The s u l p h u r d i o x i d e was o b t a i n e d from the A n s u l Chemical Company, M a r i n e t t e , W i s c o n s i n .  The 6 pound c y l i n d e r s *  c o n t a i n i n g l i q u i d sulphur d i o x i d e , a r e equipped w i t h a needle v a l v e to r e g u l a t e the f l o w o f gas., Erom the v a l v e c a p i l l a r y tubing- l e a d s i n t o a r e s e r v o i r o f l i q u i d through which the gaa bubbles r i s e . Glass t u b i n g  petrolatum, leads  from t h i s p o i n t through the w a l l to the a d j a c e n t room where i t e n t e r s the a i r i n t a k e to the p l a n t c a b i n e t . Counts o f the number o f gas bubbles per minute g i v e a rough e s t i m a t i o n o f the amount o f gas being e m i t t e d t o t h e c a b i n e t . The method used to determine the exact  concentrat-  i o n of sulphur d i o x i d e I n the c a b i n e t was t h a t of G r i f f e n and Skinner  ( 5 ) . By means o f a s u c t i o n pump a gram molecular  volume o f a i r from the p l a n t chamber i s bubbled through an  a b s o r b e r c o n t a i n i n g 100 p o t a s s i u m i o d i d e and bubbled  tower. The  and t i t r a t e d  solutions  a-second  b l u e end  thiosulphate, using a precise c . c . The  the e q u i v a l e n t  containing  difference  absorber i s  passed through a  between the two  by a s m a l l p r e s s u r e e q u a l i z i n g t a n k , and  was  readings  absorbed, regulated  measured  by  the a i r p a s s e d b e f o r e e n t e r i n g  t h e a b s o r b e r . The manometer was  c a l i b r a t e d with, a wet  m e t e r w h i c h had been p r e v i o u s l y  calibrated  test  by p a s s i n g t h r o u g h  a known volume o f a i r from a l a r g e a s p i r a t o r . The  o f a i r was  forced  meter by w a t e r adjusted  from the a s p i r a t o r t h r o u g h the wet  from t h e t a p . The  t o pass 22.4  N.  5 c c . burette with  The f l o w o f a i r t h r o u g h the a b s o r b e r was  it,  flasks  p o i n t w i t h .001  o f the s u l p h u r d i o x i d e  a U-manometer t h r o u g h which  iodine,  a r e t h e n drawn o f f i n t o  t o the same l i g h t  r e a d i n s t o .02 equals  s t a r c h . Through  the same volume o f a i r which has  soda-lime  sodium  e.c. of a s o l u t i o n  litres  a p p a r a t u s was  volume test  finally  o f a i r t h r o u g h the a b s o r b e r s .  in a definite  i n t e r v a l o f time and the manometer r e a d i n g f o r  this  recorded.  r a t e was The  recorded lights  temperature  but n o t c o n t r o l l e d .  the t e m p e r a t u r e  90' P. a t t h e end room t e m p e r a t u r e variation relative  and  relative  Owing t o t h e p r o x i m i t y o f the  varied  greatly, r i s i n g  o f the l i g h t  p e r i o d and  d u r i n g the p e r i o d  i n temperature h u m i d i t y which  h u m i d i t y were  t o about  falling  to  o f ' d a r k n e s s . The  caused a d i u r n a l v a r i a t i o n i n fell  d u r i n g the  light  p e r i o d and rose d u r i n g the dark p e r i o d . During the l a s t experiment an attempt was made to c o n t r o l the h u m i d i t y by the i n s t a l l a t i o n o f a h u m i d i s t a t i n each c a b i n e t . Each h u m i d i s t a t was connected to a h e a t i n g element i n the water tank i n the base o f the c a b i n e t , iihen the h u m i d i t y f e l l below the d e s i r e d percentage t h e h e a t i n g element was s w i t c h e d on a u t o m a t i c a l l y causing the water t o evaporate more f r e e l y thus i n c r e a s i n g the h u m i d i t y . When the h u m i d i t y rose the element was s w i t c h e d o f f . This method was f e a s i b l e d u r i n g the p e r i o d o f darkness when the temperature remained f a i r l y constants but d u r i n g the p e r i o d o f l i g h t the temperature r o s e above 90'E. c a u s i n g a drop i n the r e l a t i v e h u m i d i t y w h i c h c o u l d n o t be overcome by the e v a p o r a t i o n o f water u s i n g t h i s a p p a r a t u s . T h i s means o f changing the h u m i d i t y has an e x c e s s i v e l a g p e r i o d i n i t s r e a c t i o n to the h u m i d i s t a t and does not g i v e s a t i s f a c t o r y c o n t r o l o f the r e l a t i v e h u m i d i t y , .however, the r e a d i n g s f o r the two c a b i n e t s agree r e a s o n a b l y w e l l , so t h a t the c o n d i t i o n s were s i m i l a r and the v a r i a b l e f a c t o r s were p a r a l l e l except f o r the presence o f s u l p h u r d i o x i d e I n one. The p l a n t s used and method o f growing them* i h e p l a n t s used f o r the f i r s t and second experiments were D u c k b i l l b a r l e y , a pure l i n e o f seed and s e l e c t e d f o r u n i f o r m i t y o f growth, o b t a i n e d from the department of Agronomy, o f the U n i v e r s i t y , and two v a r i e t i e s o f dwarf beans f o r tne 3rd. and 4 t h experiment, B r i t t l e Wax i n exper-  -a-  iment 3 and M a s t e r p i e c e i n experiment 4» A q u a n t i t y o f r i c h loam s o i l s u f f i c i e n t f o r t h e experiment was o b t a i n e d from the U n i v e r s i t y greenhouse. I t was w e l l mixed to i n s u r e u n i f o r m i t y . The water h o l d i n g capa c i t y o f t h i s s o i l was then determined. Aluminum cups w i t h p e r f o r a t e d bottoms, l i n e d w i t h f i l t e r paper were used f o r the  s o i l samples. Ten siamples o f s o i l were d r i e d to- c o n s t a n t  weight a t 103'G. The cups were then immersed i n water t o t h e l e v e l o f the s o i l w i t h i n and water a l l o w e d to s a t u r a t e t h e s o i l . They were then a l l o w e d to d r a i n u n t i l a l l the s u r p l u s water had d r i p p e d o f f , and they were then weighed. Evapora t i o n from t h e s u r f a c e was prevented by p l a c i n g a l a r g e watch g l a s s on t o p o f each cup. The water h o l d i n g c a p a c i t y o f t h e s o i l was. found to be 8Q 5% o f t h e d r y weight o f t h e s o i l . 9  The- s o i l m o i s t u r e used i n t h e s e experiments was one h a l f the water h o l d i n g c a p a c i t y of the s o i l o r 4 0 ^ o f i t s d r y w e i g h t . In p r e p a r i n g the j a r s f o r the p l a n t s a s u f f i c i e n t q u a n t i t y of s o i l was t h o r o u g h l y mixed to i n s u r e u n i f o r m s o i l m o i s t u r e . The j a r s , two q u a r t Mason j a r s w i t h wide mouths, w h i c h ( w i t h the w a t e r i n g apparatus to be d e s c r i b e d below), had been p r e v i o u s l y weighed, were f i l l e d w i t h s o i l w h i c h was tapped down t o prevent l a t e r s e t t l i n g . A t the same time ten  samples o f s o i l were taken and weighed, then d r i e d to  c o n s t a n t weight to determine the water content of t h e s o i l at  the time* Immediately a f t e r f i l l i n g , the j a r s were weighed,  and assuming the wateE content o f t h e s o i l to be u n i f o r m , the  d r y weight of the s o i l I n each j a r c o u l d be c a l c u l a t e d from the v a l u e determined f o r the s o i l samples. A base weight was then c a l c u l a t e d f o r each j a r to b r i n g the water content to 50$ o f the water h o l d i n g c a p a c i t y o f the s o i l . S i n c e the experiment was an attempt to f i n d the r e l a t i v e amounts of water t r a n s p i r e d by two groups of p l a n t s , i t was n e c e s s a r y to prevent e v a p o r a t i o n from the s u r f a c e o f the s o i l and a t the same time to have a means o f w a t e r i n g the p l a n t s * The method used by K i e s s e l b a c h (8, p.50) was adopted w i t h s l i g h t m o d i f i c a t i o n s . A s m a l l i n v e r t e d f l o w e r pot was p l a c e d i n the bottom of the j a r . A p i e c e of f i n e g l a s s t u b i n g was a t t a c h e d to the s i d e o f a t h i s t l e tube w i t h e l a s t i c bands, and the two tubes were i n s e r t e d through the h o l e i n the f l o w e r pot wi t h the t h i s t l e tube e x t e n d i n g n e a r l y to t h e bottom of the j a r and the s i d e tube ending about one h a l f i n c h w i t h i n the h o l e . The lower e l a s t i c band p r o j e c t i n g around the tube was s u f f i c i e n t to keep them i n p l a c e i n the f l o w e r p o t . The t o p o f the t h i s t l e tube was f i t t e d wi t h a r u b b e r s t o p p e r and the s i d e tube l e f t open. When t h e j a r s were f i l l e d and the s o i l covered wi t h wax, water c o u l d be added through the t h i s t l e tube and the a i r escaped through the s i d e tube. L i k e w i s e , as water was t r a n s p i r e d by the p l a n t s a i r was drawn i n through the s i d e tube. Check j a r s were prepared to t e s t the e v a p o r a t i o n o f w a t e r . The l o s s o f water per j a r averaged 1.1 gm. over a p e r i o d o f f i f t y days and the i n d i v i d u a l r e s u l t s were i n c l o s e  «L0->  agreement* Th.erefo.re no c o r r e c t i o n was considered, to be necessary f o r water l o s s from the c u l t u r e j a r s . Owing to the d i f f e r e n c e i n s t r u c t u r e between b a r l e y and beans d i f f e r e n t procedures were f o l l o w e d from the time of p l a n t i n g * The b a r l e y seeds, which had been germinated f o r t h r e e days, were s e l e c t e d f o r u n i f o r m g e r m i n a t i o n and p l a n t e d f i v e t o a j a r . The s u r f a c e s o f the j a r s were then covered to a d e p t h o f a p p r o x i m a t e l y 2 m.m. w i t h a wax m i x t u r e of three p a r t s p e t r o l a t u m and seven p a r t s p a r a f f i n i n the 1 s t experiment.  The p r o p o r t i o n s were l a t e r changed to f o u r o f  p e t r o l a t u m and s i x o f p a r a f f i n . This i s the method d e s c r i b e d by B r i g g s and Shantz; ( l ) . The b a r l e y c o l e o p t i l e s p i e r c e d the wax c o v e r i n g i n about two days and growth i n the j a r s appeared to be normal. I n the f i r s t experiment  the percentage  of p l a n t s to  f i n i s h g e r m i n a t i n g was low, due, p r o b a b l y , to l a c k of s u f f i c i e n t oxygen w h i l e g e r m i n a t i n g . I n t h e second  experiment  f o u r h o l e s were punched i n t h e wax s e a l o f each j a r . These were a g a i n s e a l e d over a f t e r the s e e d l i n g s had come through the x?ax. I n t h i s case there was p r a c t i c a l l y 1 0 0 $ g e r m i n a t i o n of the s e e d l i n g s . The j a r s were weighed two to three times per week and were brought  to t h e i r base weights by the a d d i t i o n of  water. The s c a l e s used had a c a p a c i t y o f 4-g- k i l o g r a m s and were s e n s i t i v e to one f i f t e e n t h o f a gram. The t o t a l  weight  o f a j a r was a p p r o x i m a t e l y 2 4 0 0 gm. and the j a r s were weighed  to  .1 gm.. The  beans were p l a n t e d f o u r t o a j a r . Owing t o the  l a r g e c o t y l e d o n s t h e j a r s c o u l d n o t be waxed following  t h e c o t y l e d o n s w e l l above the s o i l ,  were t h i n n e d t o • t h e t h r e e b e s t p l a n t s experiment  days and d e f i n i t e v e n i n g days.  quantities  except  on a l t e r n a t e  t h e j a r s were weighed and  f o r a few o c c a s i o n s on which  definite  were.added. In b o t h t h e e x p e r i m e n t s of the plants  on beans i t was f o u n d t h a t a  large  percentage  about  f o u r weeks o l d . I n a l l c a s e s e v e r y p l a n t  permanently  j a r w i l t e d . I n no c a s e d i d one p l a n t remained  area  o f water were added oh t h e i n t e r -  I n the f o u r t h experiment  daily  leaf  o f water s o d u r i n g t h e  t h e j a r s were weighed and watered quantities  The p a r -  over t h e s u r f a c e  o f between 45' and 50'C.. The l a r g e  o f t h e bean p l a n t s c a u s e d a g r e a t l o s s experiment  they  per j a r i n the t h i r d  and p e t r o l a t u m m i x t u r e was t h e n poured  watered  then  and t h e two b e s t i n t h e f o u r t h e x p e r i m e n t .  at a temperature  third  immediately  p l a n t i n g . The p l a n t s were a l l o w e d t o grow u n t i l t h e  s t a l k had r a i s e d  affin  over  n o r m a l . When t h e w i l t e d  found t h a t t h e r o o t  wilted  when they were  i n a particular  In a j a r w i l t  while others  p l a n t s were examined, i t was  systems had h o t d e v e l o p e d a p p r e c i a b l y and  no r o o t n o d u l e s w e r e . f o u n d on them. A g r o w t h of mold was found immediately had  rotted  below t h e wax c o v e r and i n some c a s e s  j u s t below t h e s u r f a c e . When h e a l t h y p l a n t s were ex-  amined t h e r o o t s y s t e m with root but  t h e bean stem  was f o u n d t o be e x t e n s i v e and c o v e r e d  n o d u l e s . A growth o f mold was f o u n d  i t was more e x t e n s i v e i n t h e j a r s  i n these  jars  also  i n which t h e p l a n t s had  wilted.> The mold a p p a r e n t l y a t t a c k e d the "bases of the stems of those p l a n t s which w i l t e d but caused no s e r i o u s e f f e c t s on those p l a n t s which s u r v i v e d . There may  a l s o have been some  I n j u r y to the p l a n t s caused by the heat of the wax when i t was  a p p l i e d . Those p l a n t s which d i d not w i l t when f a i r l y  young remained h e a l t h y u n t i l the end of the  experiment.  Therefore to o b t a i n u n i f o r m m a t e r i a l the p l a n t s which showed no s i g h o f w i l t i n g a f t e r a few weeks were s e l e c t e d and  evenly  d i s t r i b u t e d among those to be t r e a t e d and those t o serve as controls. Measurement of l e a f a r e a . Barley. Ta o b t a i n a c c u r a t e comparisons of the amount o f water t r a n s p i r e d i t was necessary  to o b t a i n the l e a f area of  the p l a n t s . To measure i n d i v i d u a l l y by graph paper or by a p l a n i m e t e r , the a r e a o f e v e r y l e a f would take too long? so an e a s i e r method was sought. The method of comparing the weight o f p i e c e s of l e a f o f known a r e a w i t h the weight of a l l the l e a v e s was  not used because the l e a v e s v a r y a g r e a t d e a l i n  t h i c k n e s s and t h e r e f o r e i n weight compared to a r e a . Graf-Marin  (4) found t h a t t h e r e i s a c o r r e l a t i o n between the  area of b a r l e y l e a v e s and the product of t h e i r l e n g t h s .widths. H i s method was  used i n t h i s experiment.  times  A number of  l e a v e s of a l l siz.es were p l a c e d under a t r a n s p a r e n t sheet of c e l l u l o i d and t h e i r o u t l i n e s t r a c e d w i t h a p l a n i m e t e r , which had been p r e v i o u s l y checked w i t h known areas to determine the  a c c u r a c y of the i n s t r u m e n t .  The a r e a s obtained were p l o t t e d  on a graph ( J i g . l ) w i t h the p r o d u c t s o f t h e i r l e n g t h times w i d t h . The v a l u e s were found to f a l l e i t h e r s i d e o f a s t r a i g h t l i n e w i t h i n a s m a l l d i s t a n c e . The f a c t o r f o r converti n g the product of the l e n g t h times w i d t h to the area was found to be .70, w i t h v a r i a t i o n s between .556 and .890. The area, o f the stems was obtained  by measuring the l e n g t h and  t a k i n g a n average diameter about the middle o f the stem. The a r e a was then c a l c u l a t e d . To make sure t h a t the leaves measured had a c t u a l l y been f u n c t i o n a l , a l l dying leaves were removed from the p l a n t s p r e v i o u s to the second l a s t weighing and a l l the leaves, l e f t on were measured a f t e r the f i n a l weighing. Beans. Two methods were used t o o b t a i n t h e l e a f a r e a . Samples o f l e a v e s were weighed and measured by the p l a n i m e t e r . Then the t o t a l weight of the l e a v e s of a p l a n t was compared w i t h t h a t o f the measured sample and t h e t o t a l a r e a  calculat-  ed. The sample was s e l e c t e d t o c o n t a i n r e p r e s e n t a t i v e s i z e s and. t e x t u r e s of l e a v e s . The  o t h e r method was t o c o r r e l a t e the l e a f area  wi t h the l e n g t h . Graphs were made o f t e r m i n a l and l a t e r a l l e a v e s o f b o t h v a r i e t i e s . ( F i g s . 2-5). The p o i n t s on the graphs i n each case were found to f o l l o w a curve, the curves i n each o f the f o u r cases being s l i g h t l y d i f f e r e n t . These graphs were used t o f i n d the l e a f a r e a o f the p l a n t s from  "J5  1 0 l ' : 5 Area  of leaves  ~~  "25  "  i n :sq. icm„  25  "30  -14-  the Bieaaur.em.ents of the l e n g t h s of the l e a v e s . I n some cases "both the above methods were used on the same p l a n t s and were "Sfo.  found to oheclc w i t h i n l i m i t s approximating Examination  of  stomata.  Barley. For c o u n t i n g the number of stomata i n d i f f e r e n t a r e a s , p i e c e s of the l e a v e s and stems were f i x e d i n a s o l u t i o n of a b s o l u t e a l c o h o l and a c e t i c : a c i d , p l a c e d on a s l i d e and eslamined under the  microscope.  Ebr d e t e r m i n i n g the degree of opening, the method of L l o y d (9) was used, t h a t o f s t r i p p i n g the epidermis p l u n g i n g i t immediately i n t o a b s o l u t e a l c o h o l . The  and  theory  behind the method i s t h a t the a b s o l u t e a l c o h o l dehydrates the c e l l u l o s e so q u i c k l y t h a t there Is not time f o r the c e l l s to change t h e i r shape b e f o r e the c e l l u l o s e i s hardened and t h e r e f o r e the s t o m a t a l opening remains f i x e d . A b s o l u t e a l c o h o l f i x a t i o n cannot be used f o r whole l e a v e s because t h e r e i s s u f f i c i e n t water i n the mesophyll to d i l u t e the a l c o h o l and prevent the immediate hardening  of the epidermal  L o f t f i e l d (10} made comparisons of l e a v e s f i x e d by method with, l e a v e s examined w h i l e a l i v e and s t i l l  cells.  this attached  t o the p l a n t and found t h a t the two methods gave s i m i l a r r e s u l t s . The w r i t e r assumed f o r purposes o f t h i s  experiment  t h a t L o - f t f I e l c L s r e s u l t s were c o r r e c t . To make the stomata r  more c l e a r l y v i s i b l e the s t r i p s are s t a i n e d i n Congo Red, s a t u r a t e d s o l u t i o n i n a b s o l u t e a l c o h o l , f o r a day  before  a  -15examining,* They may be examined i n a b s o l u t e according passing  t o L l o y d t h e s l i d e s may be made permanent b y  t h e t i s s u e t h r o u g h c l o v e o i l and m o u n t i n g i n B a l s a m , It i sdifficult  epidermis  a l c o h o l , or  to o b t a i n a l a r g e p i e c e o f b a r l e y  due t o t h e r i d g e s and p a r a l l e l d e p r e s s i o n s  on i t s -  s u r f a c e . The u p p e r s u r f a c e i s - so d e e p l y r i d g e d t h a t a l l attempts to o b t a i n the epidermis  resulted i n obtaining  shreds o f v a s c u l a r bundles w i t h the epidermis  above them  o n l y . The s t o m a t a l i e i n l o n g i t u d i n a l d e p r e s s i o n s t h e bundles: and t h i s p o r t i o n o f t h e e p i d e r m i s  between  d i d n o t come  o f f when s t r i p p e d . F o r t h i s r e a s o n t h e l o w e r s u r f a c e was used f o r a l l the samples because the r i d g e s a r e n o t a s l a r g e and  the epidermis  c o n t a i n i n g t h e s t o m a t a c a n be s t r i p p e d ' o f f .  A shallow  c u t was made a c r o s s  the l e a f w i t h a sharp  s c a l p e l and a s m a l l p i e c e o f t h e e p i d e r m i s piece of epidermis  was r a i s e d . The  was t h e n g r a s p e d by t h e f o r c e p s ,  stripped  down t h e l e a f a n d w i t h t h e same movement o f t h e h a n d p l u n g e d Into a v i a l of absolute  a l c o h o l . I n examining the s t r i p ,  s t o m a t a i n t h e p o r t i o n f i r s t r a i s e d by t h e s c a l p e l w e r e n o t measured. The  l e a f s a m p l e s t a k e n were t h e s e c o n d y o u n g e s t  l e a f i n e a c h c a s e , t o be s u r e  t h a t t h e s t o m a t a were m a t u r e  and  still  f u n c t i o n i n g . Samples were t a k e n f r o m t h e t r e a t e d  and  c o n t r o l p l a n t s a t i n t e r v a l s throughout the day.  -16• Transverse  measurements were ma.de o f s e v e r a l  s t o m a t a w i t h a f i l a r m i c r o m e t e r . The s i z e s were d i v i d e d i n t o s i x groups as f o l l o w s : S'X_2L.G  0  o-  & c*  GJ-.O S GCL»  S i s E 1 e « » & u.p "to 1 &.(5x1 & -1- ©  &&&o  S-X. Zt.&  "fc.o 3 p Qui. ©.  S o l t o 4 . 4u . S i z e 4 « .«,. 4,5 t o 5.8u»  I t was f o u n d t h a t t h e s t o m a t a c o u l d he p l a c e d i n these  s i s e groups q u i t e a c c u r a t e l y , by j u d g i n g  o f o p e n i n g w i t h t h e eye.,  supplemented w i t h  the degree  occasional  m i c r o m e t e r r e a d i n g s . The number o f s t o m a t a i n e a c h g r o u p p e r h u n d r e d s t o m a t a was r e c o r d e d  f o r each sample, and the  a v e r a g e w i d t h o f t h e s t o m a t a i n e a c h sample was c a l c u l a t e d . Beans. The number o f s t o m a t a p e r s q u a r e mm. o n u p p e r a n d lower  s u r f a c e s o f t h e bean l e a v e s was c a l c u l a t e d u s i n g t h e  c o l l o d i a n method,, A d r o p o f c o l l o d i o n i s p l a c e d on t h e l e a f and a l l o w e d  t o f o r m a t h i n f i l m . When t h i s h a r d e n s i t i s  s t r i p p e d o f f and examined,  F o r s t o m a t a l measurements t h e  u n d e r s u r f a c e was u s e d s i n c e t h e r e i s . a p p r o x i m a t e l y t e n times  t h e number o f s t o m a t a p e r s q u a r e mm. o n t h e l o w e r  s u r f a c e a s on t h e u p p e r s u r f a c e  ( T a b l e 9 ) . Tlie l e a v e s  n o t be s t r i p p e d b y making a p r e l i m i n a r y c u t because a r e t o o t h i n . To o b t a i n a a t r i p a r i d g e on t h e u n d e r  could  t h e leaves, surface  -17-  c a u s e d by  s m a l l v e i n was g r a s p e d w i t h t h e f o r c e p s and t h e n  t o r n i n a d i r e c t i o n a t r i g h t angles t o the v e i n . I n t h i s way a p i e c e o f e p i d e r m i s was o b t a i n e d • w i t h v e r y  little  o t h e r t i s s u e c o n n e c t e d t o i t . I t was i m m e d i a t e l y p l u n g e d i n t o a b s o l u t e a l c o h o l and s t a i n i n g was f o u n d t o be u n n e c e s s a r y . L e a f samples  o f d i f f e r e n t ages were t a k e n f r o m t h e  t r e a t e d and c o n t r o l p l a n t s . T r a n s v e r s e measurements o f t h e s t o m a t a were made w i t h a f i l a r  micrometer.  On one o c c a s i o n s u f f i c i e n t s u l p h u r d i o x i d e ' was g i v e n t o cause v i s i b l e  l e s i o n s . The l e s i o n s f i r s t  appeared  as w a t e r s o a k e d a r e a s . Samples were t a k e n o f t h e e p i d e r m i s f r o m t h e w a t e r s o a k e d p a r t s and f r o m t h e n o r m a l p a r t s o f t h e same l e a v e s and samples the  were t a k e n f r o m c o n t r o l l e a v e s a t  same t i m e . These l e a f samples were t a k e n w i t h i n one h a l f  hour o f the time the i n j u r y o c c u r e d . Comparisons of  t h e degree  were made  of opening of the stomata i n a l l cases. Method o f t r e a t i n g d a t a .  T r a n s p i r a t i o n measurements. For  e a c h e x p e r i m e n t t a b l e s have been made s h o w i n g t h e  amount o f t r a n s p i r a t i o n  i n grams p e r j a r p e r d a y d u r i n g t h e  greater part of the period orated  o f g r o w t h . T h i s d a t a has been  incorp-  i n a graph i n c l u d i n g the c o n c e n t r a t i o n and d u r a t i o n o f  s u l p h u r d i o x i d e . A second  t a b l e gives the t r a n s p i r a t i o n of t r e a t -  ed a n d c o n t r o l p l a n t s i n grams p e r h o u r p e r s q u a r e d u r i n g t h e l a s t few days  metre  o f t h e e x p e r i m e n t . The l e a v e s were  -18measured on. the l a s t day of the experiment and i t i s assumed t h a t v e r y l i t t l e Increase i n l e a f area w i l l have occured I n tlie t h r e e days p r e c e d i n g measurement, Stomatal measurements. In Experiment  2 a graph was made w i t h the average  t r a n s v e r s e measurement of stomata p l o t t e d a g a i n s t the time I n hours a f t e r the b e g i n n i n g of l i g h t o r of darkness. I n Experiments: 2, 3, and 4 the data i s g i v e n as percentage stomata open, p a r t i a l l y o r e n t i r e l y , open stomata.  of  and average w i d t h o f  -19-  DATA.  F i r s t Experiment. P l a n t m a t e r i a l usedr D u c k b i l l b a r l e y . History of p l a n t s : Seeds s e t to germinate  Nov. 1 7 .  Seeds p l a n t e d and j a r s s e a l e d ................. H O Y . 1 9 . J a r s p l a c e d I n p l a n t chambers ................. Dec. 1 . Periods of sulphur d i o x i d e  treatment:  J a n . 1 7 , 9 : 3 0 P . I . to J a n . 1 9 , 4 : 3 0 P.M. Concentration:  average .2 p a r t s p e r m i l l i o n .  J a n . 2 5 , 6 : 0 0 P.M. to J a n . 2 9 , 1 : 0 0 P.M. Concentration:  . 4 1 to . 5 7 p.p.m..  J a n , 2 9 , 5 : 3 0 P.M. t o J a n . 3.1. 5 3 0 P.M. Concentration? Total treatments  .3 t o .5 p.p.m.. 182  hours.  P l a n t s measured and d i s c a r d e d ....,.».........* J a n . 3 1 . Environmental Soil:  conditions:  R i c h loam s o i l . Water h o l d i n g c a p a c i t y - 8 0 . 5 $ . S o i l m o i s t u r e used - 4 0 $ o f d r y w e i g h t .  L i g h t : Two 1 0 0 0 Watt lamps above each c a b i n e t , 5-f f e e t , above the p l a n t s . 1 6 hours p e r day.  -20Temperature:  58*]?. t o 91'F.  A v e r a g e d a i l y maximum  - 77.5'F.  A v e r a g e d a i l y minimum  - 65.0'F.  - Relative humidity:  3 1 $ t o 6.2$;.  A v e r a g e d a i l y maximum  - 56.8$".  A v e r a g e d a i l y minimum  - 42.0$.  Appearance of p l a n t s a f t e r treatment:  The l e a v e s o f t r e a t e d p l a n t s were a s l i g h t l y l i g h t e r green than those of the c o n t r o l p l a n t s . A f t e r the treatment o f .2 p.p.m. there was p r a c t i c a l l y no v i s i b l e i n j u r y t o the p l a n t s . F o l l o w i n g  the treatment o f .5 p.p.m  I r r e g u l a r l y shaped a r e a s bleached to a y e l l o w i s h w h i t e appeared on t h e l e a v e s s t a r t i n g from the t i p s . The w h i t e merged i n t o brown on the edges o f the a r e a s ,  Second Experiment. P l a n t m a t e r i a l used:  Duckbill barley.  H i s t o r y of p l a n t s : Seeds s e t t o germinate  *  Seeds p l a n t e d and j a r s s e a l e d  Jan. 31. Feb. 3.  Shoots appeared above wax s e a l and j a r s p l a c e d i n plant cabinets  Feb. 5.  A i r a t i o n h o l e s s e a l e d over and j a r s brought to base weight  Feb. 8•  -21P e r i o d s of s u l p h u r d i o x i d e t r e a t m e n t : Feb. 18 t o Feb. 20, 21 hours, p e r day. Concentration:  average .32 p.p.m..  Feb. 21 to Mar. 13, 21 hours per day. Concentration:  average .22 p.p.m..  Mar. 18 t o Mar. 23, 21 hours p e r day. Concentration: Total treatment:  average .18 p.p.m.. 588 h o u r s .  Samples o f l e a v e s o f t r e a t e d and c o n t r o l p l a n t s taken on the f o l l o w i n g days: Mar, 9,  38 t h day, 12M., 2 P.M..  Mar. 10, 3 9 t h day, 12M., 2, 7, 8, 9, 10 P.M.. Mar. 1 1 , 4 0 t h day, 8, 10, 11:30 A.M., 2, 5 P.M.. Mar. 19, 4 8 t h day, 3, 4:30 P.M.. Mar. 21, 50th day, 8:30, 10:30 P.M.. Mar. 22, 51st day, 9, 10:30, 11:3.0 A.M., 3, 5, 9:15P.M. Mar. 2 3 , 52nd day, 10 A.M., 2. P.M.. P l a n t s measured and discarded:  Mar. 2 3 .  Environmental c o n d i t i o n s : Soil:  As i n Experiment One.  L i g h t r As i n Experiment One. Temperature:.  59 * F .  t o 92*F.  Average d a i l y maximum Average d a i l y minimum  - 77 F , ,  68.7 *F.  -22Relative  humidity :  23$ t o 56$.  Average  d a i l y maximum -  47.6$.  Average  d a i l y minimum -  36.8$.  Appearance  of p l a n t s  after  treatment:  There was a s l i g h t leaves  o f b o t h t r e a t e d and c o n t r o l  of younger the  browning o f the t i p s  leaves  plants.  o f the  Some o f the t i p  became d r i e d out b u t n o t b l e a c h e d  during  l a s t .treatment. Third  Plant  material  History  of  used:  Experiment.  Dwarf b e a n s ,  sealed  Periods  \  i n plant  29 t o S e p t . light  Sept.  -  2,  ,17  14 t o S e p t .  d u r i n g the l i g h t Concentration: limits Sept.  -  16,  . 1 t o .26  Concentration: .10 t o  .11 p . p . m . ,  s i x hours  p e r day  period.  21 t o S e p t .  -  p e r day d u r i n g  p.p.m.  average  d u r i n g the l i g h t  limits  treatment:  s i x hours  average  .08 t o  J u l y 27 Aug.  period.  Concentration: limits  cabinets  w i t h wax.  of s u l p h u r d i o x i d e  Aug. the  Wax'variety.  plants:  Beans p l a n t e d and p l a c e d Jars  Brittle  .2 p . p . m . ,  p.p.m. 26,  s i x hours  p e r day  period.  average  .175  .21 p . p . m .  p.p.m.,  8  -23-  Leaf samples taken on the days o f t r e a t m e n t . P l a n t s measured and d i s c a r d e d ............... Sept. 26, Environmental conditions? •Soil:  As i n Experiment One.  L i g h t : Pour 1000 Watt lamps per c a b i n e t , 5-f- f t . above the p l a n t s . 11 to 12 hours per day. Temperature:  65 'F. to 95'F.  Average d a i l y maximum - 88.4'F. Average d a i l y minimum - ?1.7; F. t  R e l a t i v e humidity?  38$ to 73$.  Average d a i l y maximum - 63$. Average d a i l y minimum - 46.7$. Appearance o f p l a n t s a f t e r treatment. There was no v i s i b l e i n j u r y to the p l a n t s . Both t r e a t e d and c o n t r o l groups appeared to be s i m i l a r .  Fourth Experiment. P l a n t m a t e r i a l used: Dwarf beans, Master p i e c e v a r i e t y . H i s t o r y of p l a n t s . Beans p l a n t e d , f o u r per j a r .................. J a n . 1. The two best p l a n t s per j a r s e l e c t e d , the o t h e r s removed and t h e s u r f a c e o f the j a r s waxed ..... J a n . 25.  *~24P e r i o d s of s u l p h u r d i o x i d e treatments Feb. 20, f o u r hours d u r i n g the l i g h t p e r i o d . Concentration;  average .11 p.p.m.,  l i m i t s - .09 to .14 p.p.m.. Feb. 23, f o u r hours d u r i n g the l i g h t p e r i o d . -Concentration:  average .16 p.p.m.,  l i m i t s - o i l t o .18 p.p.m.» Feb. 27 to Mar. 1, f o u r hours per day d u r i n g the l i g h t p e r i o d . Concentration:  average .15 p.p.m.,  l i m i t s - .08 to .17 p.p.m.. Mar. 3 t o Mar. 9, seven hours p e r day d u r i n g the l i g h t p e r i o d . Concentration:  average .24 p.p.m.,  l i m i t s - .11 to .32 p.p.m.. Mar. 14 to Mar. 19, t e n hours p e r day d u r i n g the l i g h t p e r i o d . C o n c e n t r a t i o n : , average .17 p.p.m., l i m i t s - .12 t o .19 p.p.m.. T o t a l treatment 94 h o u r s . Leaf samples taken on the days o f t r e a t m e n t . P l a n t s measured and d i s c a r d e d  Mar. 20.  Environmental c o n d i t i o n s : Soil:  As i n Experiment One.  L i g h t : Four 1000 Watt lamps above each c a b i n e t , 5-f f t . above the p l a n t s .  12 t o 13 h o u r s per T e m p e r a t u r e : 58'P.  day.  t o 99' F.  A v e r a g e d a i l y maximum-  93 F.  A v e r a g e d a i l y minimum-  66'P.  R e l a t i v e h u m i d i t y : 25$ t o  1  89$  A v e r a g e d a i l y maximum-  64$  A v e r a g e d a i l y minimum- 36.5$ Appearance of p l a n t s a f t e r B o t h t r e a t e d and  treatment. control plants were.similar i n  appearance u n t i l the treatment i n j u r y o c c u r e d . The r o s e t o ,32 sized  9 when c o n s i d e r a b l e  c o n c e n t r a t i o n at the time of the  injury  p.p.m. w h i c h c a u s e d i n j u r y t o v i g o r o u s medium  l e a v e s o f a good g r e e n c o l o u r . Tlie y o u n g e r l e a v e s  b e l o w 5 cm. 8 cm,  of Mar.  i n l e n g t h and  o l d e r l e a v e s above  i n l e n g t h were u n i n j u r e d . The  approximate^  l e a v e s most b a d l y  a t t a c k e d w i l t e d f r o m t h e base o f t h e main p e t i o l e and d r i e d out c o m p l e t e l y . The first  i n j u r e d areas  a p p e a r e d as w a t e r s o a k e d a r e a s  f r o m t h e v e i n s . The normal.  The  on o t h e r  leaves  i n t h e r e g i o n s removed  r e g i o n s c l o s e to the v e i n s  i n j u r e d areas d r i e d  soon  out c o m p l e t e l y  remained in a  few  h o u r s l e a v i n g a d r y l i g h t brown p a p e r y a r e a . A s e c o n d of l e s s e x t e n t occured  d u r i n g t h e t r e a t m e n t -of Mar.  t h e c o n c e n t r a t i o n was  119  the r e l a t i v e h u m i d i t y  42$.  p.p.m., t h e t e m p e r a t u r e  injury  17 when  S 3 P. 1  and  -26T a b l e 1. Transpiration  i n grams per day.  F i r s t Experiment. J a r So. C 1. C 2. C 3. C 4. C 5. C 6, C 7. C 8« C 9. CIO. 1  No. o f Plants 3 3 2 3 3 4 3 3 3 5  Total 32 Average per j a r Average per p l a n t  T 1. T 2. T 3. T 4. T 5. T 6. T 7. T 8, T.9.  26 -30  30-33  No. of days of growth. 33-51 61-63 63-69 51-61  8 .73 10 .63 6 .9 10 .87 8 . 55 12 .8 10 .3 8 .27 7 .87 10 .5  12.5 12.6 6.8 12.1 4.5 13.5 11.6 9.9 8.6 9.5  17.0 17.5 16.2 17.7 12.4 19.0 17.9 17 .2 17.7 19.6  95 .42 101.6  172.2  35.8 43.1 21.9 37.6 28.1 38.1 41.4 36.2 39.4 40.2  55.5 48.5 35.9 52.1 40.6 51.5 55.7 48.7 ' 52.1 47.8  57.3 68.5 37.3 55.9 32.65 60.25 38.45 49.7 56.6 65.6  322.35 361.8  488 .4  522.25  10.16  17.22  29.29  32.24  36.18  48.84  52.23  2 .98  3.17  5.38  9 .16  10.08  11.30  15.25  16 .33  24.6 51.5 42.6 37.6 28.8 31.6 23.6 36.7 29.1  PT 34.7 49.6 48.8 43.9 37.6 40.6 31.9 55.3 39.1  PT 27.5 34.6 24.2 27 .6 22.5 27.4 33.9 32.2 21.9  9.3 2 2.3_ 11.5 14.8 5.2 11.5 14.0 21»*o 6.0  Total 30 Average per j a r Average per p l a n t  115.6  5  292.9  33.3 34.1 31.4 35.9 27.3 30.45 41.8 30.3 30.3 27.5  73-75  9 .54  3 5 3 4 2 3 3 5 2  C Control ^T Treated PT.... Periods  29.7 29.5 28.5 29 . 6 26.8 31.1 28 .2 28.9 31.2 29.4  69-73  10.4 22 0 11.9 9.6 6.7 13.1 13.6 23 • 3 6.6  16.1  25.3  19.0 17.9 11.8 19.5 18.6 22.8 16.7  32.0 28.5 27 .7 33.0 29.7 32.3 27 .7  - 3 PT 30.1 31.9 32.0 31.6 30.1 27.2 26.1 40.8 27.8  165.2  259.3  278.6  306.1  381.5  251.8  28.8  31.0  34.0  42.3  26 .1  10.2  12.71  op  o  ft  117.2  12.84  13.02  18.35  3.83  3.91  5.51  plants. plants. of treatment.  « L  8.64  9.29  8.4  -27T a b l e 2.. Transpiration  In grams p e r clay.  Second. E x p e r i m e n t . Jar No. \  No. o f Plants  C 1, C 2. C 3. C 4. .0.5. 0 6. C 7. C 8. C 9. CIO.  4 5 5 4 5 : 4 4 3 3 6.  1  Total 43 Average per j a r Average per p l a n t  T 1. T 2. T 3. T 4, . T 5,. T 6. T.7. T 8. T 9. TIO. 2  . 4: 4 4 4 5 5 4 4 - 4 4  42 -.Total Average per j a r Average per p l a n t  No. o f days o f g r o w t h . 9- 16 16-19 19-21 21-31 31-37 37 -.42 42-47 47-52 9 .6 6 .9 7 .7 7 .9 7 .7 7 .8 9 .8 -8 .6 5 .9 7 .4  15.6 13.0 13.2 14.6 15.1 14.8 15.6 16.4 12.9 15.3  Z 3  33.0 34.8 28,0 •'26.1 40.1 31.1 28.3 33.1 36.4 39.8 30.7 48.1 33.7 39.1 30.2 26.8 29.6 29.6 26.0 33.5  42.6 38.4 41.2 37.9 44.4 44.7 42.9 44.1 .33.1 47.8  39.7 42.4 41.5 44.8 37.9 28.6 36.3 30.7 30.0 48.5  46.4 30.3 40.1 26.8 40.9 23.2 27.7 28.8 25.6 45 .4  79 .3 133.6 268.4 310.4 347.6 417.1 380.4 335.2 7 .9 1 .85  12 .2 12 .1 •6 .8 8 .0 7 .9 8 .7 9 .5 6 .5 8 .3 7 • 0".  13. 4 3.41  26-.S 6.72  39.1 21.3 25.0 55.5 12.4 20.3 20.1 .31.3 16.9 29.5 11.6 22.5 23.2 28.8 16.4. 2 3 . 1 18.6 28.7 16.6 3T.15  31.0  34.8  7.21 ••' 8.08 • fT 46,5 50.5 28.8 43.8 35.7 35.2 40.2 34.8 45.6 41.7  ET 41.9 57.5 34.9 45.2 38.1 39.9 49.6 33.9 50.3 40.3  41.7 9.7 FT 45.9 DO » * o 34.6 46.2 40.2 35.8 ' 52.1 37.2 45.9 43.7  38.0 8.85  33.5 1 7.79  PT 27.1 26.3 37.0 49.5 . 37.1 ..32.3 28.5 34.3 37.8 •32 * 3 41.7 30.5 31.8 ,3.9.4 34.0 32.8 37. 9 < 46.9 31.4 26.3  87 .0 182.1 289.9 402.8 431.6 436 .8 331.9 3,63.0 8 .7 2 .07  18 .2 4.34  C... . . C o n t r o l p l a n t s . T...Treated plants. PT..Periods of treatment.  1  30.3 21.2 27 .5 47.2 33.2 26 .3 30.8 28.5 20.8 23.4  2.9.0 6.9  40.3 9.58  43.2  43 .7  10.25 10v37  3.3.2 7.9 ,  36.3 8.64  ILoja_t.r„oJL Treated P e r i o d of) t r e a t m e n t w i t h c o n c e n t r a t i o n  i n p a r t s ipen mi 11 i o n  N. B. Dayj o f growth" i s m i d - p o i n t betwejen beg i n n i!rig and end of J2©?liod„Qj^  •3  -28Table 3-. Transpiration Jar No. 1. 2. 3. 4. 5, 6. 7.  No. o f Plants 2 3 2 2 • 3 2  3  2 '3 Total 22 Avera_ per j a r Average per plant  T 2. 3.. 4. 5. 6. 7. 8. 9.  2 2 3 3 3 2 2 3 3  Total 23 Average per j a r Average Per p l a n t l 'T. PT c  3  Control Treated Periods  In grams per day.  T h i r d Experiment. 14-17  17-20  17.6 31.5 23.8 12.9 28.5 21.8 30.8 20.6 21.8  20.6 58.8 26.8 14.4 '35.4 25.2 30.6 '22.1 25.2,  28-33 37.5 54.2 53.0 29.1 69.3 42.7 41.7 31.6 27.8  33- 35  No. o f days o f growth. 35-37 37-44 44-46 46-50  13.6 32 .1 33.2 33.3 40.4 55 .6 72 .5 • 71.7 36 .8 74 .3 102 .8 83.0 22.9 45 ..4 59.0 60.6 38.5 76 .7 101.6 97.8 37.9 - 72 .9 66.6 74.1 25.0 51 7 70.7 70.5 21.6 57 1 74.7 77 .8 17.8 30 3 . 31.3 41.8  31.0 52.2 97.7 55.0 64.1 40.4 65.0 42.5 26.0  55.7 75.3 89.2 49.0 84.8 74.5 70.5 73.5 59.5  50-52 66.4 74.9 125.4 90.1 72.8 81 .8 92.4 95.2 56.2  52-55'  55'57  52.2 82.1 67.4 101 .7 71.7 102.0 '73.4 54.7 70.4 ' 98.3 70.7 ' 83.8 73. S 86.6 51.0 75.8 42.0 68.7  57-59  '59-61  66.8 80.9 87.2 67.3 98.3 86,2 93.0 72.0 63.3  -47.7 116.4 87.7 76. i 66.5 59.4 79.0 75.3 65.1  209.3  259. T  386.9  254.5  496 1  510.0  474.7  23.2  632 .0  29.7  43.C  28.3  715.0  673.2  55. 2  67.9  67.8  52.8  70 .2  84.1  63.5  83 .'7  79.5  74 8  22. 5  23.26  23.2  21.6  28 .7  32.5  26.0  34.  32.5  .30.6  73.7 50.4 85-. 8 35.3 57.5 87.9 27.] 52.8 41.2  45.1 45.6 80.3 30.C 35.7 4fe.5 27.4 37.5 35.0  74 70 5 86 0 63 7 73. 0 75. 2 59. 0 67. 8 68. 5  PT 84.0 59.2 56.4 66.5 84.5 62.8 74.2 67. ] 84.0  PT 82.5 6C .9 76.6 '6E .4 74.5 74.5 75.9 9C.1 8S.6  PT 98.7 73.5 66.4 65.4 67.6 80. 9 79.8 78.6 68.4  -9.13  20.1 30.7 28.3 25-. 5 30.2 35.2 26.1 27.4 28.9 252.4 28.1 10.9  11.78  23 . 6 30 .7 32 .5 30 .4 34 2 36 1 30 9 25 9 32 1  17.6  22 .5 45 62 .6 22 .8 39 7 67 9 35 2 22 1 35 7  11.56  16,0 31.3 38.9 18.9 27.6 26.8 20.1 17.9 20.8  44.0 34.9 73.4 15.1 2S.0 65.7 11.8 29.1 37.9  276. 4. 353. 7 30. 7 12.03  plants. plants. of treatment.  39. 5 15.53  24.; 12.2  PT 64.6 40.6 93.7 25.9 40.6 84.4 25.2 44.4 34.4  r  .  572.4  PT 64 . 7 72.3 78.6 47.7 67.2 47. C 59.7 41.0 70.2 -54.4 85.4 62.4 66.4 47.7 71.2 62.6 75.0 56.0  753.7  453.8  511.7  379.1  637.9  638.4  491.1  638.7  696 .0  37.9  680.3  50.2  56.7  42.1  70.8  71.0  54.5  71.0  77.4  14.81  75.6  19.7  22.2  16.4  27.7  27.7  21.4  27.7  3C.2  29.6  T a b l e 4. Transpiration  In crams per day.  F o u r t h Experiment. No. o f P l a n t s 29- 32 32-34 34- 36 36- 39 39-41 , No. o f days o f growth. 41- 43 43-45 45-46 46-47 47-48 48-50 50-51 51-52 52-54 54-55 55-57 57G 1. 2 26 .7 46.7 39 . £ 41 .7 '58.5 60 .3 68.6 74.2 111.2 98.4 74.5 C 2. 2 20 .8 36.3 96.2 119.4 101.0 100.6 42 . 5 38 .6 48.6 54 .7 68.5 106.8 51.4 63.2 85.3 89.2 68.7 0 S. 2 26 .8 37.5 91.0 98.4 76.f 34 .8 39 .4 46.3 96.2 97.1 56 . 9 62.8 57.7 85.6 82.3 74.3 C 4. 2 85.3 17 .2 78.2 66.3 24.5 4t 36 .5 33 .7 51 .8 58. 36.2 56 .4 54.7 64.4 81.2 89.7 82.3 • 95.6 C 5. 2 20 .0 37; 4 34 .7 34 .0 48.9 93.6 105.9 ll'.b 99.4 94. 56 .8 58.2 61.2 90.6 74.8 69.0 86.8 C 6. 2 71.2 74.4 24.9 45.3 62.7 59. 64.7 34 .1 43 .6 46.7 63 .1 55.3 91.6 105.9 98.3 88.8 0 7. 1 91.4 10].5 100^6 18 .7 37.3 79. C 95.8 28 .7 38 1 49.3 98.7 55 1 63.5 61.4 87.4 80.6 70.7 92.1 98.6 86.1 78.1 89.6 97.9 Total 13 155 1 265.0 250 269 1 334.5 434 414.5 453 .7 657.2 613.; Average 528.3 Sc5.6 663.5 632.7 520.0 566.0 612.9 per ja r 22 2 37.8 35 7 38 g 48.1 61 7 58.3 64.7 93.7 87.! Average 75.5 90.7 94.5 90.5 74.3 80.7 87.5 per p l a n t 13 0 20.4 19 2 20 7 25.7 33 4 31.9 34.9 50.5 47.; 40.7 49.0 51.0 48.7 40.C 43.5 47.2 Jar No. 1  T T T T T T  2  1. 2. 3. 4. 5. 6.  2 2 2 •2 2 2  Total 12 Average per j a r Average per p l a n t C *T PT J  3  35. 0 21. 3 22. 4 19. 8 22. 2 31. 8  50.1 36.8 38.4 31.7 39.3 39.5  PT .8 100.3 114.4 121 .4 78.3 106.1 97. 75.7 84.2 98.3 75.1 117.8 114 .9 92.8 134.7 67.7 64.8 78.4 73 .8 123.7 89.2 64.2 74.1 98.£ 104 2 87. £ 93.7 113.1 74.7 112.3 78. 0 94.8 88.1 100.9 3  41.1  43.8  51.5 66.3  47.2  41.7 44.9  90.1 43.6  60.1 68.7 64.2 65.6  58.3 74.2 56.4  62.5  68.2  152.5 235.8 258.7 249.6 360.4 387.1 399.5 458.2 626.5 598 25.4 12.7  39.2 19.7  43.1 2i.6  Control plants. Treated plants. Periods of treatment.  41.6 20.8  60.1 30.1  64.5 32.2  66.5 33.3  76.3 104.3 -38.2  52.2  99, 49.  0 573.5 604.3 7 8  95.5 ICC. 7 47.8  50.3  PT 125.1 111 .3 119.8 85.9 116.4 ]14.7 673.2  .6 .0 .4 .0 .2 .5  PT 1C2.7 104.8 103.8 95.3 106.9 113.6 95.6 104.7 107.3 86.8 87 . 2 97.7  58-59  -62 62-64 64-  116.3 119.6 95.0 97.2 53 .2 52.4 95.1 97.6 62 .6 64.2 105.8 103.6 124.1 109.8 652.1 93.2 50.1  PT 108.4 93.2 158.7 108.1 116.0 121 .2  62.7 48.1 49.5 76.4 39.6 56.3 72.4  58.2 56.1 48.3 71.8 43.7 55.4 56.1  70.4 41.2 48.9 87.6 42.2 54.3 74.9  76-  7 8  60. 41, 50.4  436.3 519.5 405.0 339.6 419.5 318.6  83,5  85.1  70.5  57.8  55.6  59.9  45.5  49.G  37.8  45.0  45,8  37.9  5.5  39.9  31.1  30.0  32.3  24.5  FT FT 72.3 97.2 95.5 75.4 80.4 88.1 91.4 74.2 64.7 104.8 113.6 104.1 92.1 99.7 97.1 79.8 73.3 105.4 95.3 76. 7 68.9 86.0 1C1 .S 76.1  48.0 28.3 54.7 52.2 51.1  46. 7 59.4 54.3 63.6 70. £ 62.6  PT 43.6 56.4 55.7 64.2 61.6 50.0  PT 36.2 59.1 52.4 69.8 68.0 56.9  PT 40.9 63.2 45.1 71.6 72.3 60.2  PT 34.4 50.6 31.S 60.7 50.8 41.1  103 100 104 102. 98. 84.  456.7 581.2 594.8 486.  9G.C  76.1  47.1  .9  49. s  j.g.c  58.7  57.5 91.7 46.2 90.1 61.2 67.8 85.0  70.2  .7 603.5 602.9 705.6 592  50.1  76.2 78.4 27.8 76.1 34.2 77.7 65.9  92.0  .9 ICO.3 100.2 117.6 50.2  83.9 78.4 39.3 89. £ 49.7 69.1 83.4  644.9 491.5 585.6 596.6 493.0  94.2 112.1 56.1  65-66 66-68 68-69 69-71 71-73 73-74 74-76  74.3 113.0 96 84.6 87.4 99 44.1 49.3 43 88.0 104.2 10£ 47.6 57.3 67 79.1 76.7 9] 73.8 97.2 95  331.5 344.4 353.5 268.8  96.8  81.0  55.1  57.3  58.8  44.8  48.4  40.5  27.6  26.7  29.4  22.4  .  I  _ _ F i g u r e _8 .  Transpiration  i n grams per p l a n t  per  day!  per  day.  [. T h i r d E x p e r i m e n t .  Nb.  of days' of growth.  Transpiration  i n grams per  ......  •  ..j  :~r~ plant  .. ...  F o u r t h Experiment,,  Period  ofj treatment) w i t h c o n c e n t r a t i o n ) . I n  N .BDay  of. growth i s  p a r t s (per  million  m i d - p o i n t between b e g i n n i n g and  end jof  T a b l e 5. Plant area for  final  and r a t e period  First  of t r a n s p i r a t i o n o f measurement.  Experiment.  Jar No. o f No. o f No. p f Stem L e a f T o t a l No. - P l a n t s Stems Leaves A r e a A r e a P l a n t - . Area , _ • p cm. cm. cm. C 1. C 2. C 3. C 4. G 5. C 6. C 7. C 8. C 9. CIO.  2 3 3 4 3 3 3 5  8 7 5 8 7 7 6 9 8 10  32'  75  1  Total  3  A v e r a ge pen j a r •7  T T T T T T T T  5 3 4 .2 3 3 5 2  2. 3. 4. 5i 6. 7. 8. 9.  Total  30  Average per j a r  221  7.5  T 1. Z  19 25 15 22 20 24 17 21 27 31 .  6 10 7 7 : 7 7 10 8 8 70 7.8  •  209 163 171 162 185 174 117 191 152 183  256 287. 234 387 343 419 253 308 419 416  1707 3322  721 738 640 935 870 1012 623 807 990 1015  Transpiration final period of 51 h o u r s ,  Transpire ation i n gm./hr./m of plant surface.  114.6 gm. 137.0 74.6 111.8 65.3 120.5 76.9 99.4 113.2 131.2  29.8 39.9 22.85 23.4 14.74 12.22 24.25 24.1 22.46 25.7  8351 1044.5 gm.  239.42  22.1  171  332  835  104.5 gm.  23.94  14 23 20 27 19 14 24 22 16 ;  124 192: 169 142 153 206 187 148 146  211 295 301 318 237 221 273 282 182 .  546 782 771 775 627 647 733 712 510  55.0 •gm. 69.3 48.5 55.1 45.1 54.8 67.9 64.4 43.7 gm.  19.8 17.4 12.32 13.94 14.1 16.63 18.15 19.57 16.83  1467 2320 . 6103  503.8 gm.  148.74  179 19.9  163  C .... . C o n t r o l plants.. T.....Treated plants. ^ L e a f area,"one s i d e only. 4 T o t a i plant area includes area of leaves.  258  678  56.0  16.53  2  . . . o f stems and b o t h s i d e s  -31. Table Plant area  and. r a t e  for f i n a l  period  6. of t r a n s p i r a t i o n  o f measurement.  Second E x p e r i m e n t . Jar No.  N'o. Of Plants  No. o f Stems  No. o f Leaves  Fresh Weight  Stem Area  gm. C C C C C C C •C C  !. ..4 2. 5 • : 3. 5 4. 4 '•: 5. 5 6-. ' . 4 7. .. . 4 . 8. 3 9.. 3 6 cio.;  6 9 6 7 10 9 9 7 6 9•  20 23 21 18 24 21 ' 20 18 15 26  Total 43 Ave.ra ge per j a r  78  206  1  T 1. ••' 4 T 2. 4 T 3. 4 T 4. . 4 T. 5. . 5 ' T 6. 5 T 7. 4 : T 8. 4 T 9. 4 TIO. . •4 2  Total 42 A v e r a ge per jar  7.8 11 10 12 9 11 7 10 5 . 7, 10 92 • !: 9.2  sq.  Leaf Area  cm. s q .  16.8 149.8 1.4.3 144.3 16 .0 134.6 11.8 111.6 17.2 . 173.4 13.3 131.2 14.1 142.2 13.2 •113 .6 11.6 . 114.6 19 .6 193 .0 :  3  cm. s q .  419. C 371.0 392.5 283.5 433.0 324.0 333 .0 350.7 514.0 546.0  147.9  1408.3  20.6  14.8  140.8  23 27 28 18 28 21 ' 24 12 24 20  12.7 17.6 15.1 15.2 16.4 14.8 14.6 14.9 15.9 13.6  153.6: 283.0 212.1 401.5 175.6 596 .5 194.3 312.0 178.3 376.0 147.7 347.0 157.. 4 . 361.5 187 .7 245.0 168.9 407.0 159.6 284.0  225 22.5  C.....Control plants. *T.....Treated plants. L e a f area,.one s i d e o n l y . T o t a l plant area Includes area  Total Plant , Area  3766 .7  987.8 886,3 919.6 678.6 1039.4 779.2 808.2. 815.0 742 .6 1285.0  1735.2  3413.5  15.1  173.5  341.4  gm.  19.33 14.25 18.25 16.93 16.40 17.22 14.30 14.70 17.23 14.72  8941.7  1675.7  gm.  163.33  894.2  .167.6  gm.  16.33  719.6 131.4 gm. 1015.1 247.6 968.-6. 161.3 818.3 171.4 930.3 161.5 • 841.7 208.5 880.4 - •' 197.1 677.7 170.2, 982.9 .234.3 727.6 131,7 gm.;  15.2.0 20.30 13.89 17 .45 14.47 20.70 18.68 20.90 19.85 15.10  8562.2 856 o 2  18.15.0 gml 181.5  1  3  4  Transpiration in gm./hr./sq. metre of plant s u r f a c e .  231.8 151.5 200.7 133.8 204.5 116 .1 138.5 143.8 127.9 227.1  376.7,  150.8  Transpiration : final period of cm. 120 h o u r s . 4  o f stems and b o t h s i d e s  of leaves.  gm.  .176 .54 17.65  T a b l e 7. Leaf area for  and r a t e  final  period  of t r a n s p i r a t i o n o f measurement.  T h i r d Experiment.. No. o f Plants  C C C C C C C C C  1  Leaf A r e a i n s q . cm. 3  !. 2 2. ; , 3 3. 2 4. 2 • 5. 3 6. 2 7. 3 8. •" 2 9.. 3  Total .  22  Average per j a r T 1. T 2. •T .3. T 4. T 5. \ T 6. T 7. T 8. T 9. 2  Total Average per j a r  1  3  2 2 3 3 3 2 2 3 3 23  .  Transpiration i n gm. : f i n a l p e r i o d o f 48 hours.  Transpiration i n gm. p e r h r . p e r s q . metre of l e a f surface.  1774.1 2380.9 2293.0 1873.0 2010.0 1931.0 2040.5 2513.3 1646.0  95.4 232,8 175.4 152.2 . 133 .0 118.7 .158.0 .150.6 130.1  11.20 20.64 15.96 16.94 13.70 12.80 16.69 12.28 16.47  18,461.8  1346.2  136.68  2051.3  149.6  15.18  1933.5 1784.0 1644.4 1427.0 2047.8 172*9.0 1327.0 1551.0 2041.1  197.3 147.0 132.9 130.8 135.2 161.9 159.5 .159.2 136.8  21.25 17.17 •16.83 20.20 13 .73 19.59 25.00 21.35 13.95  15,484.8  1360.6  168.98  1720.5  151.1  18.77  C.....Control plants. ....Treated plants. L e a f a r e a , one s i d e .  T a b l e 8, Leaf  a r e a and r a t e of t r a n s p i r a t i o n d u r i n g f o u r l a s t  periods  o f measurement  Fourth Experiment. 71st-73rd Jar No.  •No. o f Plants  No. o f L e a f Leaves Area p  cm. C C C •C C C G  2 2 2 2 2 2 1  66 50 61 60 52 50 56  13  395  1. 2. 3. 4. 5. 6"^ 7.  Total  Average per j a r  Transpiration gm/hr.  73rd-to74th Rate ^per uh i t leaf area  No. o f Leaves  Leaf Area cm.  2.62 ' 17.2 2.00 12.3 2.06 22.9 3.19 20.0 1.605 18.4 2.71 30.0 3.00 19.3  47 47 60 58 49 48 52  1033.6 1483.2 859.7 1511.3 842.7 840.1 1352.6  8907.2 17.18 140.1  361  7923.2  day  Transpira t i on gm/hr 2.42 2.33 2.00 3 .00 1.83 2.29 2.33  7 4 t h - 7 6 t h day Rate per unit leaf area  No. o f Leaves  Leaf Area O cm. d  23 .4 15.7 23.2 19.85 21.7 27.3 17.2  39 42 50 56 43 46 52  16.20 148.35  328  782 .1 1307 .9 694 .4 1455 .3 760 .0 821 .4 1352 .6  Trans- Rate" spir'per ation unit gm/hr leaf area 2.92 1.71 2.04 3.66 1.75 2.25 3.12  7173 .7 17.45  32 38 42 52 40 46 52 302  51.6 1131.9  2.31  21.19  46.9 1024.8  2.49  25.5  43.1  2 2 2 2 2 2  44 63 44 73 76 76  1.81 2.71.  21.3 30.8 38.0 28.0 17.2 15.3  42 61 44 73 73 76  797.5 843.0 611.7 953 .3 1368.0 135.8.2  1.50 2.46 2.17  18.8 27.9 35.5 30.7 20.7 18.1  39 61 43 73 70 76  1.71 2.61 1.875 3.00 3.00 2.50  22.5 31.1 31.2 31.5 22.5 18.4  39 47 38 48 53 53  12  376  6255.2 14.17 150.6  369  5931.7  14.34 151.7  362  4697.2 14.69 157.2  278  851.0 880.9 611.7 953.3 1500.1 1358.2  62.7 1042.5  2• 32 2.67 2.58 2 .08  2.36  25,. 1  61.5  988.6  C.....Control plants. T.....Treated plants. Rate o f t r a n s p i r a t i o n i n grams p e r h o u r p e r s q u a r e  2»02 2.83 2.46  2.39  25.3  60.3  706.7 843.0 601.6 953.3 133 5.0 1358.2  782  2.45  metre o f l e a f s u r f a c e , one  side only.  26.2  Leaf Area  Tran spination gm/hr  cm^  20.0  1  3  37.4 13.1 29.4 25.1 23.0 27.4 23.0  No. o f Leaves  2.45  Average per j a r  Z  7 6 t h - 7 8 t h day  56.4 1272.4  T 1. T 2. T 3. 4. 5,  Total  1526.0 1562.7 897.5 1595.0 872.9 900.5 1552.6  dav  46.3  616.9 1174.2 546.9 1327.7 - 690.1 821,4 1352.6  Rate per unit leaf area  2.69 1.39 1.36 2.92 .805 1.735 1.89  43.70 11.85 24.90 22.20 11.67 21.20 14.00  6579.8 12.79 149.52 940.0 706.7 481.9 554.6 275.1 1012.7 776.9  :  1.83  21.36  . 1.69 1.29 1.76 1.375 2.53 2.18  23.90 27.30 31.80 50.00. 25.00 28. 10  3807.9 10.82 634.6  1.67  186.10 31.01  -34Table Number of stomata  9. per square mm.  Duckbill barley Leaf sheaths Leaves Upper s u r f a c e Lower s u r f a c e  32 32.9 28.8  B r i t t l e Wax beans leaves Upper s u r f a c e Lower s u r f a c e  43 395  M a s t e r p i e c e beans Leaves Upper s u r f a c e Lower s u r f a c e  40.8 335  Table  10.  T r a n s v e r s e measurements Plant  of  stomata.  A v e r a g e w i d t h of stomata Control  Treated unin jured  i n microns.  Treated injured  Barley Medium aged l e a v e s  1.5 l u .  1.6 l u .  B r i t t l e Wax beans Medium aged l e a v e s  3.29u.  2.46u.  M a s t e r p i e c e beans Young l e a v e s  3.48u..  3.75u.  3.86u.  Medium aged l e a v e s  3.97u.  3,49u.  4.08u.  Old Leaves  2.6 2 u .  2.28u.  2.02u.  F i g u i-e 11.  „ ... jlverage taken a f t e r  w i d t h of stomata  various  periods  per  of  Leaf sampl 3  l i g h b and of d a r k n e s s .  Second E x p e r i m e n t . Duckbil"L b a r l e y .  0  CQ  <  o 2u  •— • • •• o  X  : %  •  '• X  o X x*  X •H  ferage wid  3  <  o  X  l u 't  0  x  o  <>  X  X  X  X  ° * o  oo  o  *  6 Hours of  4  2  0  2  fc  6  ft  Hours of  10  IE  ^ 4 ] J 6  light.  Control Treated  i n w i d t h of stomata i s  c o n t r o l 1.eaves as ; f o r t r e a t e d  Ei i.  1  1 )  0  darkness.  Variatioii  <«  o<  o  X  8  x X  leaves.  as  creat  for  -35-  T a b l e 11. P e r c e n t a g e Of stomata Plant  open.  Control  Treated uninjured  Treated injured  Barley Medium aged l e a v e s  73.5$  71.5/  B r i t t l e Wax beans Medium aged l e a v e s  62.7/  51.3/  M a s t e r p i e c e beans Young l e a v e s  64.2/  62.6^  61.4/  62.4/  67.3/  6 5.4/  51.8/  47.2/  48.5/  Medium aged l e a v e s Old l e a v e s  -36-  .  " '•  DISCUSSION-OP In  comparing.the  RESULTS  average t r a n s p i r a t i o n  i n grams p e r day f o r each o f the two groups ment t h e r e iment  i s considerable v a r i a t i o n  1 t h e two groups a r e f a i r l y  per p l a n t  i n each  experi-  i n r e s u l t s . In Exper-  equal u n t i l a f t e r a t r e a t -  ment o f .5 p.p.m. w h i c h caused i n j u r y , whereupon t h e transpiration  from, t r e a t e d  plants  i m m e d i a t e l y dropped  (Table 1  and P i g . 6) due, p r o b a b l y , t o t h e r e d u c t i o n i n f u n c t i o n a l l e a f a r e a by i n j u r y . there  2 ( T a b l e 2 and F i g . 7)  i s f o u n d t o be no s i g n i f i c a n t d i f f e r e n c e between the  two groups the  In E x p e r i m e n t  i f the d i f f e r e n c e s between' t h e i r average v a l u e s f o r  transpiration  calculation difference  p e r p l a n t p e r day a r e t e s t e d by a  o f t h e s t a n d a r d d e v i a t i o n from t h e mean. A of twice the standard d e v i a t i o n from the a r i t h -  m e t i c mean i s c o n s i d e r e d show a g e n e r a l t r e n d  t o be s i g n i f i c a n t  of increase  (3(). B o t h  i n transpiration  groups  t o the  4 0 t h day a f t e r w h i c h t h e r e  i s a d e c r e a s e . Presumably t h e  same f a c t o r s  i n b o t h cases and the r e d u c t i o n  1  is  are operative  p r o b a b l y due t o I n c r e a s i n g age. I n E x p e r i m e n t s 3 and 4  ( T a b l e s 3 a n d 4 and F i g . 8 and 9) t h e t r a n s p i r a t i o n t r e a t e d and c o n t r o l p l a n t s shows a g e n e r a l t r e n d  of both  of i n c r e a s e  up  t o the p e r i o d  between the 5 0 t h and 6 0 t h days o f growth  at  w h i c h p o i n t E x p e r i m e n t 3 was d i s c o n t i n u e d and E x p e r i m e n t  w h i c h c o n t i n u e d t o the. 7 8 t h day shows a g r a d u a l r e d u c t i o n in  t h e amount o f t r a n s p i r a t i o n . The- r a t h e r deep d e p r e s s i o n s  4  -37- . in  t h e g r a p h s ( P i g . 8 and 9} o c c u r e d on c e r t a i n occasions,  when t h e l i g h t s were r e d u c e d a t u r e rand h i g h e r h u m i d i t y  i n number. W i t h lower  t h e r e was a r e s u l t a n t d e c r e a s e i n  t r a n s p i r a t i o n , , T h i s shows t h a t t h e r e I s a more [ positive to  significant  c o r e l a t i o n between t h e two groups i n t h e i r r e a c t i o n  the e n v i r o n m e n t a l  humidity  temper-  than  factors  o f temperature and r e l a t i v e  there i s a negative  c o r e l a t i o n between the  c o n t r o l and t r e a t e d plants„ I n E x p e r i m e n t 3 ( T a b l e 3 and Fig*  8) t h e g e n e r a l average shows g r e a t e r  transpiration  f r o m the c o n t r o l p l a n t s than f r o m t r e a t e d p l a n t s , however the  two c u r v e s  come t o g e t h e r a t the f i n a l  d e t e r m i n a t i o n and  the a v e r a g e r a t e o f t r a n s p i r a t i o n p e r u n i t a r e a as d e t e r mined f o r t h e f i n a l  period, i s a c t u a l l y higher f o r treated  than f o r c o n t r o l as shown i n T a b l e 3, Owing to the g r e a t e r leaf  a r e a o f the c o n t r o l p l a n t s t h e t r a n s p i r a t i o n  approximately to  the 4 5 t h  be p r a c t i c a l l y  e r e d more f u l l y  from  to the 62nd days c a n be c o n s i d e r e d  t h e same* The f a c t o r o f a r e a i s c o n s i d -  below. P r e v i o u s  to t h a t p e r i o d the r a t e may  have been l e s s f r o m t r e a t e d than f r o m c o n t r o l p l a n t s * b u t the data Fig,  i s n o t c o n c l u s i v e * I n E x p e r i m e n t 4 ( T a b l e 4 and  9) the p a r a l l e l  between t h e two g r a p h s i s a g a i n  marked showing t h e e f f e c t s occurred during  this  o f v a r y i n g temperature*  very  Injury  experiment a t a c o n c e n t r a t i o n o f  .32 p.pan., and e i g h t days l a t e r a t .19 p*p,m. showing t h a t beans a r e e x t r e m e l y  sensitive  to s u l p h u r d i o x i d e ,  A c o m p a r i s o n o f the. r a t e o f t r a n s p i r a t i o n f o r t h e  final  period  of three  days  i n grams per hour  metre o f l e a f a r e a "between the c o n t r o l and shows i n E x p e r i m e n t spiration  from the t r e a t e d  The; r e d u c t i o n the  plants  two  is a slight  difference  i n Experiment  In E x p e r i m e n t for four  periods  i n the average  2 the d i f f e r e n c e  3 the d i f f e r e n c e  4 (Table  deviation  groups  to increase  s l i g h t l y during  the f i r s t  period  8) the r a t e was  than  the r a t e three  groups.  calculated of  between the  i s l e s s than the  standard is a  tendency  of t r a n s p i r a t i o n  periods,  whereas i n the  measured, t h e t r a n s p i r a t i o n from the  control plants  decreases appreciably  treated  increases^  plants  show t h a t the l i g h t was  on one day and for t h i s period  that  and t h a t from t h e  as shown i n the graph, F i g . 10.  A- s t u d y o f the hygrothermograph period  two  i s less  from the mean o f each group. There  i n b o t h groups  final  i s less  o f one t o two days each near the end  f o r the two  records  of t h i s  last  r e d u c e d f o r a few  t h e minimum and maximum  are l o w e r than u s u a l .  a c c o u n t f o r the d e c r e a s e i n r a t e  These  6  rate for  from the means o f the two  e x p e r i m e n t . Here a g a i n the d i f f e r e n c e  averages  2 and 3 ( T a b l e s  from the mean o f the  t w i c e the s t a n d a r d d e v i a t i o n  tran-  t o i n j u r y would a c c o u n t f o r  groups, but i n E x p e r i m e n t  g r o u p s , and  less  plants  than, from the c o n t r o l s .  r e d u c e d t r a n s p i r a t i o n . In E x p e r i m e n t s  t h a n the s t a n d a r d d e v i a t i o n  the  treated  5) s i g n i f i c a n t l y  i n l e a f a r e a due  and 7) t h e r e the  1 (Table  per square  hours  temperatures circumstances  of t r a n s p i r a t i o n  -39f o r the- c o n t r o l p l a n t s . The i n c r e a s e d  r a t e of t r a n s p i r a t i o n  f r o m t h e t r e a t e d p l a n t s may be a s e c o n d a r y e f f e c t o f t h e i n j u r y w h i c h o c c u r r e d p r e c e d i n g the p e r i o d under Badly i n j u r e d leaves  were removed so t h a t t h e r a t e  be c a l c u l a t e d on a b a s i s o f f u n c t i o n a l l e a f a r e a * i s o n o f t h e number o f l e a v e s t h i s p e r i o d w i t h 'the i n c r e a s e during  the p e r i o d  of leaves  as shown i n t h e f o l l o w i n g  0  25 0 36 37 38 42  A compar-  i n rate of transpiration  the increase  the number  i n transpiration,,  table;  of leaves  'removed* 0 14  3  could  removed i m m e d i a t e l y p r e c e d i n g  shows r o u g h l y t h a t t h e g r e a t e r  removed t h e g r e a t e r  fo, of J a r H T o  discussion.  5  25 17 23  Change i n t r a n s p i r a t i o n . compared w i t h p r e c e d i n g  period,  + 114 " 3" & Q + =6 + '18»5  +  -f-  a, 5 9,7  I t I s p o s s i b l e t h a t t h e r e m o v a l o f the i n j u r e d l e a v e s  caused  i n c r e a s e d l o s s o f w a t e r a t t h e p o i n t s where t h e y were removed f r o m t h e stem. The r e s u l t s f r o m t h e measurements o f s t o m a t a show the  same l a c k o f a n y s i g n i f i c a n t d i f f e r e n c e between t r e a t e d  p l a n t s n o t showing v i s i b l e i n j u r y and c o n t r o l p l a n t s * I n E x p e r i m e n t 2. ( E i g , 11} t h e measurements f r o m i n d i v i d u a l leaves  show g r e a t  v a r i a t i o n s w i t h i n t h e c o n t r o l g r o u p and  w i t h i n t h e t r e a t e d g r o u p . When e a c h g r o u p i s a v e r a g e d t h e y show no s i g n i f i c a n t d i f f e r e n c e  ( T a b l e 10}„ E x p e r i m e n t  3  -40( T a b l e 10); on the aperture  o t h e r hand, shows a w i d e r average  f o r c o n t r o l p l a n t s than  the d i f f e r e n t  determinations  the. o n l y case where t h e r e  storaatal  f o r t r e a t e d p l a n t s , and  are q u i t e c o n s i s t e n t . This i s  is a significant  difference.  In  E x p e r i m e n t 4 t h e r e i s no s i g n i f i c a n t d i f f e r e n c e between stomatal apertures of but  of the c o n t r o l  t r e a t e d l e a v e s and there  leaves, of u n i n j u r e d  of i n j u r e d areas  is a distinct  d i f f e r e n c e i n stomatal aperture  of stomata open between yoimg, medium aged and  leaves,  ( T a b l e 10), the medium aged l e a v e s h a v i n g  the  agree with susceptible and  the  a v e r y harrow a p e r t u r e . These  i n appearance  dioxide affects  w a t e r s o a k e d a r e a s . The  the  results  injury.  leaf  no n o t i c e a b l e  of i n j u r e d  areas  a r e a s . I t i s p o s s i b l e t h a t the cells  w a l l s then  making t h e m . f r e e l y  p r o d u c e the t h i n  of the e p i d e r m i s  the m e s o p h y l l  s o l u t i o n I n the moist  of  and  t o s u l p h u r d i o x i d e . Mien s t r i p p e d from the  compared w i t h m n i n j u r e d  cells  old  o b s e r v a t i o n t h a t medium aged l e a v e s a r e most  examined under the m i c r o s c o p e t h e r e was  difference  and  widest  s t o m a t a l a p e r t u r e , the young l e a v e s s l i g h t l y narrower o l d leaves having  areas  of t r e a t e d l e a v e s ,  percent  the  the  first,  penetrates  permeable and  d r y i n g out  p a p e r y patches  thus  by g o i n g and  into  kills  causing  the  the  of t h e s e dead a r e a s  w h i c h a r e the f i n a l  sulphu  would  form  -41-  C01TCLTJSI0E3.  The c o n c e n t r a t i o n s  a t which- i n j u r y -occurred show-  t h a t beans a r e more s u s c e p t i b l e t o t h e i n j u r i o u s e f f e c t o f sulphur  d i o x i d e t h a n barley» When i n j u r y occurs- medium a ged l e a v e s  s u s c e p t i b l e a n d young a n d o l d l e a v e s  a r e most  a r e more r e s i s t a n t *  Sulphur- d i o x i d e i n c o n c e n t r a t i o n s - w h i c h d i d c a u s e i n j u r y r e d u c e d t h e t r a n s p i r a t i o n from, t r e a t e d p l a n t s by ' reducing  the f u n c t i o n a l l e a f  area,  There was no e v i d e n c e o f pronounced  e f f e c t on  the t r a n s p i r a t i o n o f plants- t r e a t e d w i t h ' sulphur at concentrations  w h i c h d i d n o t cause  dioxide  injury»  There was no e v i d e n c e o f a s i g n i f i c a n t  difference  between t h e degree o f opening o f stomata o f c o n t r o l p l a n t s and t r e a t e d p l a n t s • T h i s was t r u e o f s t o m a t a f r o m a r e a s w h i c h h a d b e e n i n j u r e d . , The s u g g e s t i o n sulphur  d i o x i d e a f f e c t s the meaophyll  causing  injury„ . Although negative  t o be c o n c l u s i v e  i s made t h a t t h e c e l l s f i r s t , when  r e s u l t s c a n n o t be  the evidence from the f o r e g o i n g  Indicates that sulphur  considered experiments  d i o x i d e i n the c o n c e n t r a t i o n s  used  w h i c h d i d n o t cause i n j u r y * under t h e c o n d i t i o n s o f l i g h t  r  t e m p e r a t u r e and r e l a t i v e h u m i d i t y w h i c h p r e v a i l e d a t t h e t i m e does n o t c a u s e a marked e f f e c t o n t h e t r a n s p i r a t i o n o r  -42-  s t o m a t a l o p e n i n g s * The c l o s u r e o f s t o m a t a r e c o r d e d i n E x p e r i m e n t 5 i s a n e x c e p t i o n w h i c h i s n o t c o n f i r n e d "by t h e o t h e r results-» The e v i d e n c e from-'.these experiments.,,- a l t h o u g h indecisive*  i s a g a i n s t the t h e o r y t h a t ' s u l p h u r d i o x i d e  causes I n v i s i b l e i n j u r y i n c o n c e n t r a t i o n s below those w h i c h cause v i s i b l e  injury*  /'  SUMMARY. Four E x p e r i m e n t s were c o n d u c t e d , plants treated  a n d two. o n bean plants,, w i t h s u l p h u r dioxide,  half  o f the p l a n t s  calculations  ion per unit  being  and h a l f u s e d a s c o n t r o l s .  R e c o r d s were made o f t h e t r a n s p i r a t i o n and  two. on "barley  from the plants?  were made o f t h e f i n a l r a t e  of transpirat-  o f l e a f a r e a . Measurements o f s t o m a t a were  made i n t h e two g r o u p s and- comparisons 'drawn. The  results  showed no s i g n i f i c a n t i n c r e a s e o r  d e c r e a s e i n t h e amount o f t r a n s p i r a t i o n or  i n either  barley  beans due t o the e f f e c t o f s u l p h u r d i o x i d e when u s e d i n  c o n c e n t r a t i o n s w h i c h d i d n o t cause Injury«, Where t h e s u l p h u r d i o x i d e transpiration  caused i n j u r y the  was r e d u c e d .  There was i n two experiments, no s i g n i f i c a n t difference  between the- o p e n i n g s o f stomata o f t h e two  groups» I n one e x p e r i m e n t t h e r e was a s l i g h t b u t d e f i n i t e r e d u c t i o n i n the s i z e . o f  t h e s t o m a t a l a p e r t u r e i n the  treated, p l a n t s » I t has been c o n c l u d e d t h a t support effect.  to t h e " I n v i s i b l e i n j u r y "  the d a t a g i v e no  theory o f sulphur  dioxide  ' -44-  .BIBLIOGRAPHY 1. B r i g g s , L . J . , and S c h a n t z , determining moisture, 2. D a v i s j "A.  t h e lower  H. L. limit  A wax s e a l method f o r  of available  soil  B o t . Gaz. 51:210-219.. 1911.  R., and Hoagland, D. R.  An a p p a r a t u s  growth o f p l a n t s i n a c o n t r o l l e d  f o r the  environment.  Plant  P h y s i o l o g y 3:277-292. 1928. 3. F i s h e r , R. A.  S t a t i s t i c a l methods f o r r e s e a r c h workers.  O l i v e r and Boyd, E d i n b u r g h . 1932. 4. G r a f - M a r i n , A.  S t u d i e s on powdery mildew o f c e r e a l s .  C o r n e l l U. A g r i c . E x p . S t a . Memoir 157. 1934. 5.  Griffen,  S. W. , and S k i n n e r , W.'W.' ..Small amounts o f  s u l p h u r d i o x i d e i n the atmosphere. I . Improved method for  d e t e r m i n a t i o n o f s u l p h u r d i o x i d e when p r e s e n t i n  low  concentrations i n a i r .  I n d . and E n g . Chem. 24  1932. 6 . •Holmes', J . A., F r a n k l i n , E . C., and Gould, of  the Selby Smelter  Interior, 7.  J a c k , W. R.  Commission.  Bureau o f . M i n e s .  Bull.  98. 1915.  The a b s o r p t i o n o f i n o r g a n i c n u t r i e n t s by  University  8. K i e s s e l b a c h , T. A. production. 1916.  Report  U. S. Dept. o f t h e  plants t r e a t e d with sulphur dioxide. thesis.  R. A.  Unpublished  o f B. C. 1937.  T r a n s p i r a t i o n as a f a c t o r Bull.  i n crop  A g r i c . E x p . S t a . N e b r a s k a . No.. 6.  -45-9.  L l o y d , F. E .  The-physiology.'of  Wash. Pub. 10. L o f t f i e l d ,  82.  J . V.  G.  The  S c a r t h , G.. W. factors 504.  13.  low  F l u c t u a t i o n s i n the  Ben.  D e u t s c h . Bot.  ( B i o l . A b s t r a c t s 4: No.  Zimmerman, P.  concentrations and  14. .Swain, R.E.,  and  Ind. and  46:  1930.)  and  other  P l a n t P h y s i o l o g y 7:481-  W.,  and  C r o c k e r , Wm.  Cruciferae.  Johnson, A.  B-.  Effect  A c t i o n a t low  Hill,  G. R.  d e r Holzgewachse.  1933.  Zimmerman, P.  W.,  dioxide  concentrations.  R e l a t i o n of s u l p h u r and  P l a n t Phys. 12:309.-383.  Uber d i e E i n w i r k u n g  ilation  of s u l p h u r  Chem. 28:42-47, 1936..  Thomas, M..-D..,. and  16. W i e l e r , A.  of  1938.  Eng.  alfalfa.  Effect  C o n t r . Boyce Thompson I n s t .  i n the atmosphere t o p h o t o s y n t h e s i s  17.  619.  Ges.  of s u l p h u r d i o x i d e on y i e l d  on wheat development.  543.  Carnegie  1932.  9:179-198.  of  Inst.  1921.  on s t o m a t a l movement.  alfalfa  15.  o f stomata.  Mechanism of the a c t i o n of l i g h t  S e t t e r s t r o m , C., of  314.  of photosynthesis.  383-391. 1928. 12.  behavior  Krasnosselsky-Maximov.  course  Carnegie  1908.  I n s t . Wash. Pub. .11. Maximov und  stomata.  von  I n s t . 6:455-470.  d i o x i d e gas. 1934.  1937,  Jahrb. Wiss. Bot.  C r o c k e r , Wm.  containing sulphur  respiration  Sauren a u f d i e A s s i m -  ( B i o l . A b s t r a c t s 8: No. and  dioxide  78:483-  15234. 1934.)  Toxicity  of a i r  C o n t r . Boyce Thompson  

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