POTASSIUM IB" RELATION TO TRANSPIRATION IN THE TOMATO BY Donald Richmond Le G a l l a i s A Thesis submitted i n P a r t i a l F u l f i l m e n t o The Requirements f o r the Degree of MASTER OP SCIENCE IN AGRICULTURE i n the Department of HORTICULTURE The U n i v e r s i t y of B r i t i s h Columbia SEPTEMBER, 1941 TABLE OP CONTENTS Introduction . Review of L i t e r a t u r e . . . . . . . . . . . 2 Object of Experiment . . . . . . . . . . . . . . . . . . . . 7 M a t e r i a l s and Methods I. The Nutrient Solutions . . . . . . . . 7 I I . Growing the P l a n t s . . . . . . . . . . . . . . . . . 10 I I I . The T r a n s p i r a t i o n Tests . . . . . . . . . . . . . . . . 13 ' IV. Determination of Green, Dry.and Ash Weights . . . . 14 V. E x t r a c t i o n of the P l a n t Sap and Determination of i t s P h y s i c a l Chemical Constants . . . . . . . . . . 16 VI. A n a l y t i c a l Methods . . . . . . . . . . . . . . . . . 19 VI I . Further T r a n s p i r a t i o n Tests . . . . . . . . . . . < . 25 Results I. General Appearance of the Plan t s . . . . . . . . . . 27 IX v ^AjnSjlysis of k^eeds » <» • * « * © « © » # « ® « © « # . o 8 IV. The Further T r a n s p i r a t i o n Tests . . . . . . . . . . 41 X} ISC IX 33X0 XX « « « » • • « c e e c « ' B S i c e « » « . 6 « e « i t 1 4 2 Xji'b©3T3J"fcLlX>6 G1 "t ©d. B « e • a « e « « • * e e • • « © « « « « 53 Acknowledgements • • . • . . 58 Append e « » • « e © . . . 59 POTASSIUM IB" RELATION TO TRANSPIRATION IN THE TOlfATO INTRODUCTION . Potassium is-one of the most abundant of the elements found i n p l a n t s , yet comparatively l i t t l e i s known of i t s exact func-t i o n . Unlike the other major e s s e n t i a l elements - carbon, hydrogen, oxygen,A. calcium, magnesium, phosphorus and sulphur. -potassium has not been found 3,s a part of any of the various organic compounds occuring i n p l a n t s . I t seems to occur in-soluble forms as i t can be completely removed by washing wi t h water (15). I t i s also the most r e a d i l y t r a n s l o c a t e d of the e s s e n t i a l mineral elements i n the pl a n t ash (9). Even though i t s - s p e c i f i c r o l e ha,s not been determined i t i s d e f i n i t e l y known to be ab s o l u t e l y e s s e n t i a l , as i n i t s absence normal growth does not occur. The many i n v e s t i g a t i o n s reported show that potassium d e f i c i e n c y r e s u l t s i n impairment of many aspects of p l a n t growth. I t was noticed that potassium d e f i c i e n t tomato p l a n t s , used i n n u t r i t i o n experiments c a r r i e d on by Department of H o r t i -c u l t u r e students, tended to w i l t before the corresponding f u l l n u t r i e n t ones d i d . A s i m i l a r observation was noted by T i n c k l e r and Darbishire (32) i n t h e i r experiment on Stachys tuber i f era Naudin. They noted that l a t e on a very hot day the potassium, d e f i c i e n t p l a n t s were w i l t e d whereas a l l the comparable p l a n t s supplied w i t h potassium were erect and t u r g i d . These observ-ations stiggested that i t would be worth while to i n v e s t i g a t e more f u l l y the Influence of potassium on t r a n s p i r a t i o n . Loss of water by t r a n s p i r a t i o n i s of considerable i n t e r e s t 2 and importance to those who work' wi t h p l a n t s , p a r t i c u l a r l y i n the dry a g r i c u l t u r a l regions, A large amount of water i s l o s t from the s o i l through p l a n t s i n t h i s way, the amount varying w i t h the d i f f e r e n t species of p l a n t s , the l o c a t i o n and the season. For t e r r e s t i a l p l a n t s of any given species the rate of t r a n s p i r a t i o n per u n i t of weight or of l e a f area i s not con-stant "but v a r i e s , "being influenced "by the f o l l o w i n g f a c t o r s ; A. C l i m a t i c f a c t o r s as, 1. Radiant energy, or the i n t e n s i t y of s u n l i g h t , 2. Temperature,. 3. R e l a t i v e Humidity, 4. A i r currents or wind; E. S o i l f a c t o r s as, 5. The degree of a e r a t i o n of the ro o t s , 6. The wa-ter content of the s o i l , 7. The concentration of solutes' i n the s o i l , 8. The mineral n u t r i e n t s i n the s o i l ; and C. i n t e r n a l f a c t o r s as, 9. Structure, e s p e c i a l l y of the l e a f , 10. The stage of growth of the p l a n t , and p o s s i b l y 11. The composition of the pl a n t sap (20). The c l i m a t i c f a c t o r s are l a r g e l y "beyond c o n t r o l , the s o i l f a c t o r s can often be brought under c o n t r o l , and the i n t e r n a l f a c t o r s , though l a r g e l y h e r e d i t a r y , are infl u e n c e d by n u t r i t i o n which i s c o n t r o l l a b l e , and i n some cases by photoperiod which can a f f e c t the growth phase of some p l a n t s . The f a c t o r s l i k e l y to be influenced by potassium i n the above observations on w i l t i n g would be 7, 8 , 9 and 11. REVIEW OP LITERATURE The e f f e c t upon t r a n s p i r a t i o n of the concentration-of the s o l -utes i n the s o i l s o l u t i o n . Not much work has been done on t h i s , "but the work done seems quite conclusive. Bouyoucos ( l ) i n h i s work on wheat 3 seedlings grown i n complete n u t r i e n t water, sand and s o i l c u l -tures showed that t r a n s p i r a t i o n per gram of dry matter de-creased w i t h r i s e i n density of the n u t r i e n t s o l u t i o n while the a c t u a l dry matter produced increased. This was true f o r the higher d e n s i t i e s only, as "below a varying lower density t r a n s -p i r a t i o n decreased w i t h decrease i n density. The same held true f o r corn and bean seedlings. Hoagland (10) working on b a r l e y observed that when pl a n t s of uniform, development were t r a n s f e r r e d to n u t r i e n t s o l u t i o n s of d i f f e r e n t concentrations, a greater t r a n s p i r a t i o n took place from s o l u t i o n s of lower con-• c e n t r a t i o n . Meyer (19) i n h i s work on the cotton p l a n t found that t r a n s p i r a t i o n per u n i t of l e a f area or of f r e s h or of dry weight of top p r o g r e s s i v e l y decreased i n amount w i t h progress-ive increase i n the concentration of any of the f o l l o w i n g s a l t s i n the s o i l , NaCl, NalTO^, KG1, GaCl2 and Ca(ITOg )g. The r e s u l t s of these three workers are i n general agreement, and i t seems to be an e s t a b l i s h e d f a c t t h a t , w i t h i n extreme l i m i t s , the i n -crease i n concentration of s o l u t e s , excluding t o x i c substances, i n the s o i l s o l u t i o n r e s u l t s i n a decrease i n t r a n s p i r a t i o n ! This f a c t i s the probable e x p l a i n a t i o n i n part at l e a s t of the r e s u l t s obtained by Lawes (16) i n 1850 and ~by Maercker (17) i n 1895. Lawes found that the a d d i t i o n of a f e r t i l i z e r c o n s i s t -ing of potassium sulphate, magnesium sulphate, sodium c h l o r i d e and mono-calcium phosphate decreased the amount of water r e -quired to produce a u n i t of dry matter i n wheat, peas and c l o v e r , but not i n beans. Maercker i n v e s t i g a t e d the influence of crude potash s a l t s , such as k a i n l t and c a r n a l l i t , on the consumption of water by mustard p l a n t s grown i n unsealed pots of s o i l i n which the amount of water was kept constant. Pie found that as' compared w i t h the plan t s grown i n s o i l without potash those having potash required l e s s water as the amount of potash was increased. The e f f e c t was much more pronounced i n the s o i l c o ntaining 27 per cent of i t s water capacity than i n that containing 60 per cent. Because h i s pots were not sealed to prevent -loss of water from the surface of the s o i l , h i s f i g u r e s show t o t a l water l o s s , not merely t r a n s p i r a t i o n a l l o s s ; nevertheless the experiment shows greater conservation of water w i t h increase i n concentration of f e r t i l i z e r a p p l i c a t i o n . The e f f e c t upon t r a n s p i r a t i o n of the mineral n u t r i e n t s i n the s o i l " . Besides the e f f e c t of t o t a l concentration of the solutes i n the s o i l s o l u t i o n there i s the separate e f f e c t of the i n d i v i d u a l ions which go to make up that t o t a l . The r e s u l t s of Lawes and of Maercker' are probably also p a r t l y due to the e f f e c t s of these i n d i v i d u a l ions as w e l l as to t o t a l concentration. I n v e s t i g -ations on the influence upon t r a n s p i r a t i o n of the mineral nut-r i e n t s , e s p e c i a l l y ¥, P and K, have also been r e l a t i v e l y scarce, and those done show considerable disagreement i n r e s u l t s . Sachs (28) i n 1859 observed that the a d d i t i o n of KUO^, (ifH^)gSO^, or gypsum to the s o i l decreased the amount of tra n s -p i r a t i o n compared w i t h that of a s i m i l a r p l a n t i n c o n t r o l s o i l . S i m i l a r l y the a d d i t i o n of NaCl or (EH 4)gS0 4 to a d i s t i l l e d water c u l t u r e decreased t r a n s p i r a t i o n . He also observed that a small amount of H1TO3 added to a d i s t i l l e d water c u l t u r e caused a great increase i n t r a n s p i r a t i o n , but a small amount of KOH caused r e t a r d a t i o n of t r a n s p i r a t i o n . B u r g e r s t e i n (2) i n 1876 5 reported that acids accelerated t r a n s p i r a t i o n and that a l k a l i e s retarded i t , t h i s "being i n agreement w i t h Sachs. He also r e -ported that s o l u t i o n s of calcium n i t r a t e , potassium n i t r a t e , potassium phosphate, potassium carbonate, ammonium n i t r a t e , magnesium sulphate, ammonium sulphate, and sodium c h l o r i d e were found to increase t r a n s p i r a t i o n up to a c e r t a i n p o i n t . These t e s t s were not reduced to one va r y i n g f a c t o r as these workers d i d not take i n t o c o n s i d e r a t i o n the separate e f f e c t s of con-c e n t r a t i o n . The same also a p p l i e s to Reed. Reed (26) i n 1910 working on wheat grown i n s o i l and i n s o i l - e x t r a c t s found that i n the case of lime and of sodium phosphate treatments the tra.nspira.tion showed m a t e r i a l i n c r e a s -es, whereas treatments w i t h potassium s a l t s decreased i t , while the e f f e c t of sodium n i t r a t e treatment was somewhat v a r i -able u s u a l l y operating however to cause a decrease i n trans-p i r a t i o n ; He found i n contrast to Sachs and B u r g e r s t e i n that inorganic acids retarded t r a n s p i r a t i o n while the e f f e c t s of organic acids were somewhat v a r i a b l e . Reed also states that potassium always showed i t s i n h i b i t i n g e f f e c t and calcium i t s a c c e l e r a t i n g e f f e c t on t r a n s p i r a t i o n whether the potassium or calcium were combined w i t h CI, NO^, or SO^. Bouyoucos ( l ) i n 1911 added e x a c t l y the same amount of complete n u t r i e n t s o l u t i o n to f i f t i e t h normal s o l u t i o n s of various s a l t s , and used these i n water and sand c u l t u r e s of wheat seedlings. The order of magnitude of the e f f e c t was not the same i n both types of c u l t u r e s f o r a l l the s a l t s . In the s o l u t i o n c u l t u r e the r e l a t i v e t r a n s p i r a t i o n was i n h i b i t e d i n 6 t h i s order: (1TH 4) 2C0 5> MgS04 >MgClg> ICgGOj > ( E H 4 ) 2 S 0 4 > KNO- > Ga(N0 3) 2 > lalTO 3 > GaClg > NagHP04> KgliPC^; ^while i n the sand • c u l t u r e i t was reduced thus: (NH 4 ) 2 S 0 4 > (NH 4) gC0 3 > }igS0 4 > Ca(lT0 5) 2 > MgCl 2> KN0 3 > CaClg > K 2C0 3> Na 2HP0 4> K 2HP0 4. Hans teen-Cranner (8) In 1914, working on wheat, oats and rye seedlings grown f i r s t i n 'normal Hnop's n u t r i e n t s o l u t i o n and then t r a n s f e r r e d to d i l u t e s i n g l e s a l t s o l u t i o n s , reported that the calcium i o n was found to exert a r e t a r d i n g Influence on water absorption and an a c c e l e r a t i n g e f f e c t on t r a n s p i r a t i o n , while potassium i n isomotic concentrations stimulated water absorption and retarded t r a n s p i r a t i o n . K i s s e r (14) i n 1927 reported r e s u l t s i n general agreement w i t h these i n h i s work on wheat plants treated i n somewhat the same "way. Since both these I n v e s t i g a t o r s used very d i l u t e concentrations of the various s a l t s employed, i t would seem that the r e s u l t s were l a r g e l y due to s p e c i f i c i o n e f f e c t s upon t r a n s p i r a t i o n and not to the concentration e f f e c t s shown-by Bouyoucos and Hoagland. Ghilders and Cowart (3) i n 1935 grew-young apple trees i n sand c u l t u r e s using f u l l n u t r i e n t , minus P, minus K, minus PK, and minus ¥> n u t r i e n t s o l u t i o n s based on Knop' s formula. They found that the t r a n s p i r a t i o n per u n i t of l e a f area was greater f o r the minus.P and the minus PK treatments than f o r the f u l l n u t r i e n t , while I t was l e s s f o r the minus K and much l e s s f o r the minus N than f o r the f u l l n u t r i e n t . James (12) i n 1930, and N i g h t i n g a l e , Schermerhorn and Bobbins (23) i n 1930 published papers d e a l i n g w i t h p l a n t s t r u c -ture i n r e l a t i o n to potassium, but neither of these papers threw any d e f i n i t e l i g h t on the r e l a t i o n of t h i s structure to t r a n s -7 p i r a t i o n . Before s t a r t i n g t h i s experiment no papers were found on the r e l a t i o n of potassium to the composition of the plant sap i n r e l a t i o n to t r a n s p i r a t i o n . OBJECT OE EXPERIMENT The purpose of the f q l l o w i n g experiments was 1. to deter-mine by a c t u a l measurement whether or not potassium d e f i c i e n t tomato plan t s t r a n s p i r e d more per u n i t of weight than d i d com-parable f u l l n u t r i e n t p l a n t s ; 2. to compare the e f f e c t of potassium d e f i c i e n c y on t r a n s p i r a t i o n i n tomato plan t s w i t h that of a' phosphorus deficiency? and that of a combined phos-phorus and potassium d e f i c i e n c y ; 3. to see i f the e f f e c t of potassium d e f i c i e n c y on t r a n s p i r a t i o n i n the tomato held good for- another type of p l a n t , f o r example, the r a d i s h ; 4. to see i f there was any r e l a t i o n between several of the p h y s i c a l chem-i c a l constants of the plan t sap of the plant s tested and t h e i r t r a n s p i r a t i o n ; 5. to see i f there was any r e l a t i o n between the chemical composition of the plan t ash and the t r a n s p i r a t i o n . These experiments were c a r r i e d on at the U n i v e r s i t y of B r i t i s h Columbia at Vancouver, B. C. during the summers of 1936 and 1937, and the 1940 - 41 term. MATERIALS AND METHODS L* 332£ N u t r i e n t S o l u t i o n s . Hoagland's n u t r i e n t s o l u t i o n s of osmotic pressure 0.72 atmospheres were made up as f o l l o w s . The stock s o l u t i o n s were made up as i n d i c a t e d i n Table I. In each case the amount of Chemically Pure s a l t i n d i c a t e d was d i s s o l v e d i n a convenient 8 amount of d i s t i l l e d water. In the case of the i r o n s o l u t i o n s , however, one -gram of s a l t was d i s s o l v e d i n water and made up to 100 cc. In the case of s o l u t i o n s No, 1 and No. 4, where two s a l t s were used i n the one s o l u t i o n , each s a l t was f i r s t d i s -solved separately. The two so l u t i o n s were then mixed and made up to a volume of one l i t e r . Table _1 The Stock Solutions No. M a t e r i a l Amount D i r e c t i o n s 1. 67 g rams Dissolve separately, mix MgS04 '7H20 100 it and d i l u t e to 1 l i t e r . 2. Ca(N0 3) 2 4H 20 207.5 11 Dissolve and d i l u t e to 1 1, KH 2P0 4 50 ti 11 11 11 II u 11 4.*- NaN03 57 11 Dissolve separately, mix MgS04 7H 20 100 11 •'and d i l u t e to 1 l i t e r . 5. - NaH 2P0 4 H 20 50 n Dissolve and d i l u t e to 1 1. 6. PeP0 4 H 20 1 ii 11. 100 cc 7. K C 1 27.5 11 " 1 1. 8, NaCl. 21.5 I I 1 1 11 11 11 11 11 9. F e r r i c t a r t r a t e 1 '. 11 " 100 cc The n u t r i e n t s o l u t i o n s were made up from the stock s o l u t i o n s i n the proportions i n d i c a t e d i n Table I I . The po r t i o n s of stock s o l u t i o n s were not mixed together f i r s t and then d i l u t e d , but were added to a considerable p o r t i o n of water which was then made up to 4 l i t e r s . This was done to avoid p r e c i p i t a t i o n of the s a l t s , i n p a r t i c u l a r of the i r o n . In the 1937 experiments stock s o l u t i o n No. 9, f e r r i c t a r t r a t e , was used i n place of No. 9 Table I I The Nutrient Solutions F u l l n u t r i e n t 22 cc. of Stock S o l u t i o n No. 1 25 ii 11 'i « ii 2 12 " " " " " 3 4 " " " " • " 6 or 9 Half f u l l n u t r i e n t and h a l f potassium -d e f i c i e n t 11 cc. of Stock S o l u t i o n No. 1 11 " " " " 11 4 26 " " " " " 2 6 " " " ." " 3 6 " " " " " 5 4 " " " " . 11 6 Potassium d e f i c i e n t 22 cc. of Stock S o l u t i o n No. 4 26 " " » 11 " 2 12 " " / " II " 5 4 " " " " » 6 or Phosphorus d e f i c i e n t 22 cc. of Stock S o l u t i o n No. 1 26 " 11 " " " 2 12 " " " " 7 zj_ II II ii II II q Combined phosphorus and potassium d e f i c i e n t 22 cc. of Stock S o l u t i o n No. 4 26 " " " " 2 12 " ! L « " II 8 4 H II II II II g 10 6, f e r r i c phosphate. This time to avoid p r e c i p i t a t i o n of the i r o n , the f e r r i c t a r t r a t e was not mixed i n wi t h the other n u t r i e n t s "but was applied separately at a l t e r n a t i n g times w i t h the regular n u t r i e n t treatment. For t h i s purpose 1 cc. of stock s o l u t i o n No. 9 was d i l u t e d to 1 l i t e r . Tap water was used i n these d i l u t i o n s as the experiment was r e l a t i v e , not absolute, and i t was thought at the time that the tap water i n Vancouver was s u f f i c i e n t l y free of d i s s o l v e d substances to cause no in t e r f e r e n c e w i t h the n u t r i e n t treatment. I I . Growing the p l a n t s . ( l ) Tomatoes 1936. The A i l s a C r a i g v a r i e t y of tomato was used. Seeds were planted i n two small f l a t s of thoroughly washed sand on May 30. Two weeks l a t e r feeding w i t h n u t r i e n t s o l u t i o n s was commenced and continued twice each week. F l a t I was given f u l l n u t r i e n t t s o l u t i o n and f l a t I I was given potassium d e f i c i e n t n u t r i e n t s o l u t i o n . -The plan t s were l e f t out of doors and watered when necessary w i t h tap water. Four weeks from the time of p l a n t i n g the seedlings were transplanted to thoroughly cleaned 4 Inch c l a y pots. The p l a n t s were d i v i d e d i n t o three s e r i e s based on n u t r i t i o n a l treatment as f o l l o w s . Series A - f u l l n u t r i e n t , 3 p l a n t s ; Series B - h a l f f u l l n u t r i e n t and h a l f potassium d e f i c -i e n t , 2 p l a n t s ; and Series C - potassium d e f i c i e n t , 3 p l a n t s . The p l a n t s f o r s e r i e s A and B were taken from f l a t I, and those f o r s e r i e s C from f l a t I I . Each pla n t was given 100 cc. of n u t r i e n t s o l u t i o n twice each week and water when needed. This treatment was continued f o r about one month a f t e r t r a n s p l a n t i n g By the end of t h i s time blossoms were forming and the t r a n s p i r -11 'ation t e s t was made commencing on July 30. (2) Tomatoes 0.937 0The Bonny Best v a r i e t y of tomato was used. Seeds were planted i n May i n f l a t s of well-washed sand. The plant s were l e f t out of doors and watered w i t h tap water when necessary. On June 12, the true leaves "being w e l l s t a r t e d , the seedlings . were transplanted to four separate small f l a t s and watered w i t h n u t r i e n t s o l u t i o n as f o l l o w s ; F l a t I - f u l l n u t r i e n t , F l a t I I - potassium d e f i c i e n t , F l a t I I I - phosphorus d e f i c i e n t , and F l a t IV - combined phosphorus and potassium d e f i c i e n t . From then on the plant s were watered w i t h n u t r i e n t s o l u t i o n i n s u i t a b l e amounts each two or three days. In between times they were watered w i t h the i r o n s o l u t i o n . About two weeks l a t e r 10 f u l l n u t r i e n t p l a n t s - Series 1, and 10 potassium d e f i c i e n t p l a n t s - Ser i e s . 2 , were transplanted to large cans of sand. The remaining p l a n t s i n these f l a t s ( I and II) were l e f t there and given the same n u t r i e n t t r e a t -ment as. those i n the cans. On July 13 7 pl a n t s from each of f l a t s I and I I were transplanted to smaller cans of sand, and from then on those from.Flat I received phosphorus d e f i c i e n t n u t r i e n t s o l u t i o n - Series 3, while those from F l a t I I received combined phosphorus and potassium d e f i c i e n t s o l u t i o n - Series 4. . The 4 f u l l n u t r i e n t p l a n t s remaining i n F l a t I were also transplanted to smaller cans of sand. These continued to receive the f u l l n u t r i e n t treatment and formed Series 5. At t h i s time, Ju l y 13, one month a f t e r the commencement of d i f f e r e n t i a l n u t r i e n t feeding, the plant s i n F l a t I I I - phos-phorus d e f i c i e n t , and those i n F l a t IV - combined phosphorus 12 and potassium d e f i c i e n t , were showing strong d e f i c i e n c y symp-toms. These p l a n t s were only about three inches high as com-pared to the f u l l n u t r i e n t and potassium d e f i c i e n t p l a n t s which were about nine inches high. Five of the best p l a n t s from-each of f l a t s I I I and IV were transplanted to small cans. From t h i s time on the phosphorus d e f i c i e n t p l a n t s - Series 6, were given f u l l n u t r i e n t treatment, and the combined phosphorus 'and potassium d e f i c i e n t p l a n t s - Series 7,, were given potassium d e f i c i e n t treatment. On August 7, almost two months a f t e r feeding w i t h n u t r i e n t s o l u t i o n s was commenced, blossoms were forming, and the t r a n s p i r a t i o n t e s t was s t a r t e d . (3) Radishes 1937. The French Breakfast v a r i e t y of r a d i s h was used. On June 23 the seeds were planted i n two f l a t s of sand. About three weeks l a t e r , J u l y 12, the radishes wefre transplanted to large cans of sand. From t h i s time on 10 were given f u l l n u t r i e n t treatment - Seri e s I , and another 10 were given potassium d e f i c i e n t treatment - Series 2. In a d d i t i o n to t h i s 2 r a d i s h p l a n t s were transplanted to small cans s e v e r a l days l a t e r and given potassium d e f i c i e n t treatment, thus becoming part of Series 2. The p l a n t s were watered .with the n u t r i e n t s o l u t i o n s about twice a week and in. between times w i t h the i r o n s o l u t i o n . On August 7, about one month a f t e r feeding w i t h the n u t r i e n t s o l u t i o n s was- commenced, the t r a n s p i r a t i o n t e s t was s t a r t e d at the same time as that of the tomatoes. (4) The Cans. The large cans used i n these experiments were about s i x inches i n diameter and about seven inches i n height, and 13 enameled on the i n s i d e . The smaller cans were about f i r e inch-es i n diameter and about f i v e inches i n height, and enameled i n s i d e and out. A hole about h a l f an inch i n diameter was punched i n the bottom of each can f o r drainage. Over t h i s hole was placed a small metal cap about h a l f an inch deep. This was to receive the cork stopper when.the t r a n s p i r a t i o n t e s t was made. The sand used i n these experiments was i n a l l cases f i r s t screened and then thoroughly washed. I I I . The T r a n s p i r a t i o n Tests. (1) Tomatoes 1936. As t r a n s p i r a t i o n was determined by l o s s of weight i t was necessary to s e a l the containers completely. This was done by means of melted parawax. Care was taken not to l e t the hot wax come ' d i r e c t l y i n t o contact w i t h the stems of the p l a n t s . The hole i n the bottom of the pot was plugged. Before being sealed each pot was w e l l watered and a l l excess Y/ater was allowed to d r a i n o f f . The. pots were then sealed, weighed, a-nd set out i n the open but i n the shade f o r 21 hours from 2:00 P.M. July 30 to 11:00 A.M. July 31. The pots were then reweighed i n the same order and set out f o r 23 hours, t h i s time i n the sun, t i l l 10:00 A.M. August 1, when they were weighed f o r the f i n a l time. (2) Tomatoes and Radishes 1937. As cans were used i n these exxoer iments only the tops were sealed and not the whole container, as was the case w i t h the pots i n 1936. The hole i n the bottom of each can was plugged w i t h a cork stopper. Before s e a l i n g , the cans were, w e l l watered and drained. At the time of s e a l i n g , a piece of glass 14 tubing about three inches long, 5/16 inch inner diameter, and f i t t e d with- a:, small cork stopper, was placed i n each can pro-j e c t i n g through the wax s e a l . This tube was used to permit a d d i t i o n of water during the experiment. A f t e r s e a l i n g the cans were weighed and set out i n the open. -As i t took about two hours to weigh a l l the cans, the weighing was done at night when the water l o s s through t r a n s p i r a t i o n was at i t s l e a s t . The p l a n t s were always weighed i n the same order and as nearly as p o s s i b l e at the same rat e so that time i n t e r v a l between any two sets of weighings would be the same, w i t h i n a few minutes, f o r a l l the p l a n t s . On August 7 the weighing was s t a r t e d at 10:20 P.M., on August 8 at 8:20 and on August 9 at 1%20. I t was planned to take weighings e a r l y i n the morning, but i t was found that the weight of dew on the p l a n t s was greater than the l o s s In weight due to t r a n s p i r a t i o n . I t was also planned to continue the experiment one or two days longer but r a i n i n t e r -vened and the experiment was terminated. On the morning of August 9 50 grams of water were added to each tomato plant i n s e r i e s 1, 2, and 5. The balance used i n these experiments i s shown i n one of the photographs appended to t h i s paper. IV. Determination of Green, Dry, and Ash Weights. At the termination of the t r a n s p i r a t i o n t e s t s , the heights of the p l a n t s were measured. The pla n t s were then cut and the green weights of tops and roots were determined separately. In the 1936 experiment, however, before the p l a n t s were cut, water was added to the pots to allow those p l a n t s which were s l i g h t l y w i l t e d to become t u r g i d again. The tomato p l a n t s 15 were cut at the surface of the wax, the r a d i s h p l a n t s at the juncture of* the leaves and root. The 1936 tomato plants were weighed to 0.1 gram, while the 1937 plants were weighed to 0.5 gram on the "balance used i n the t r a n s p i r a t i o n t e s t s , as -a more s e n s i t i v e "balance of s u f f i c i e n t s i z e was not a v a i l a b l e at the time. Most of the smallest p l a n t s , however, were weighed to 0.1 gram on a small hand balance. A f t e r the top of each of the 1937 tomatoes was weighed, the l e a f y portions were pinched o f f and the weight of the stem and p e t i o l e s was determined. A f t e r the tops had been weighed, the roots were washed as fr e e as p o s s i b l e from sand, the excess water was squeezed out, the remaining excess moisture was allowed to dry o f f , and the . roots were then .weighed, 1936 tomatoes and 1937 radishes to 0,1 gram, and 1937 tomatoes to 0.5 gram. In the case of the radishes only the e d i b l e , and not the f i b r o u s p o r t i o n was weighed. A l l the r o o t s , and a l l the tops except those used f o r plant sap e x t r a c t i o n , were d r i e d to constant weight i n an oven at 100° -105°C. The weights were taken to 0.1 gram. As the oven could take only a l i m i t e d number of samples i n weighing t i n s at one time, a l l the samples were d r i e d as soon as p o s s i b l e i n paper bags at about 70°G. f o r about f i f t e e n hours, t h i s being s u f f i c -i e n t to preserve them. A l l the tops of the 1937 p l a n t s , except those used f o r plant sap e x t r a c t i o n , were then ashed i n an e l e c t r i c muffle furnace at 600° - 650 G. Above t h i s temperature the ash. tended to fuse w i t h the c r u c i b l e . Before being placed i n the muffle, furnace, however, the d r i e d m a t e r i a l wa.s charred over a Bunsen flame 16 under the hood. Iron t a r t r a t e s o l u t i o n (3b, 9) was found use-f u l f o r marking the c r u c i b l e s . The s o l u t i o n was applied with a pointed match s t i c k to the warmed c r u c i b l e s . When strongly heated the mark became dark yet i t could be removed with "Dutch Cleanser" i f desired. The ash weights were taken to 0.001 gram on a s e n s i t i v e a n a l y t i c a l balance. The r a d i s h roots were ashed and the weights were recorded. The ashing of the 1937 tomato roots was commenced but discontinued as i t was found that a large p r o p o r t i o n of the ash weight was sand which could not be r e a d i l y eliminated or allowed f o r at that time. In determinating the dry weights an attempt was made to com-p l e t e l y eliminate the sand. This was not suc c e s s f u l but i t was found l a t e r , that the weight of the sand l e f t was, at the mostj, l e s s than 0.1 gram. V. E x t r a c t i o n of the Pl a n t Sap and Determination of I t s P h y s i c a l Chemical Constants. S i x tomato plan t s from each of s e r i e s 1 and 2, four p l a n t s from each of s e r i e s 5 and 4, two plant s from s e r i e s 5, and s i x r a d i s h p l a n t s from each of s e r i e s 1 and 2 were used i n these experiments. The methods used were based on those given i n "Biochemical Laboratory Methods" by Morrow (21), Chapter I I P h y s i c a l Chemical Constants of P l a n t Saps, ( l ) E x t r a c t i o n of the Sap. The.plants (tops only) selected f o r t h i s experiment were cut f i r s t . A f t e r each one was cut and weighed i t was placed w i t h crumbled s o l i d carbon dioxide on s, b o t t l e of convenient s i z e . This was to freeze the t i s s u e s , thus making the extrac-17 t i o n of sap easier? and also to preserve them t i l l they could "be placed i n /the r e f r i g e r a t o r . In the tomato s e r i e s 1, 2, and 5 each plant was put i n a separate b o t t l e , i n s e r i e s 3 and 4 two p l a n t s were put i n one b o t t l e , and i n the r a d i s h s e r i e s 1 and 2 three p l a n t s were put i n one b o t t l e . As soon as a l l these p l a n t s were b o t t l e d the b o t t l e s were taken to the lab o r -atory (about three miles from where the p l a n t s were grown) and placed, i n the refr i g e r a . t o r . The f r o z e n t i s s u e was ground i n a, small hand meat grinder. At a l l times i n the process everything was kept as cold as p o s s i b l e . In the tomato s e r i e s 1, 2, and 5, each plant was ground separately, and i n s e r i e s 3 and 4 the plan t s were ground i n groups of two. In the radishes the s i x plants of s e r i e s 1 were ground together, as were those of s e r i e s 2. A f t e r each p l a n t or group was ground, the grinder was r i n s e d o f f and placed i n the r e f r i g e r a t o r while the ground t i s s u e was being pressed. The ground t i s s u e was wrapped i n two paper towels which had been wetted and then squeezed i n the press. . The wrapped t i s s u e was placed i n a small c y l i n d e r ica,l metal cup of about two and three-quarters inches i n diameter and i n height, such as i s used as a small cheese mould. There were four small holes i n the bottom and several around the side of the cup. A small metal p l a t e of the same diameter as the cup was placed on the top of the wrapped t i s s u e , and a c y l i n d r i c a l block of wood was placed on top of the p l a t e . This cup was set i n a screw press, which was then screwed down as t i g h t l y as p o s s i b l e . The expressed j u i c e was c o l l e c t e d i n a metal pan placed Under the cup, and immediately b o t t l e d and placed i n the r e f r i g e r a t o r . 18 (2) Determination of Percentage of Total S o l i d s and E l e c t r i c a l Resistance.* » The j u i c e was next cleared by c e n t r i f u g i n g f o r h a l f an hour at about 1700 r . p. m. The cleared j u i c e was placed i n "50 cc. c y l i n d e r s and brought to 20*0. i n water bath. The percentage of t o t a l s o l i d s was then determined by means of a B r i x scale hydrometer (used u s u a l l y f o r sugar s o l u t i o n s ) . While s t i l l at the same temperature and i n a water bath the r e l a t i v e e l e c t r i -c a l r e s i s t a n c e of the j u i c e was determined. The j u i c e was then replaced i n the r e f r i g e r a t o r . (3) Determination of Freezing Point Depression. For t h i s experiment a Beckman thermometer and the standard f r e e z i n g p o i n t depression apparatus was used. The procedure used was as that given i n Morrow (21) f o r the determinationr.df the Hyd r o p h y l l i c C o l l o i d Content, About 10 - 12 grams of p l a n t sap was weighed out e x a c t l y to 0.001 gram and placed i n the apparatus. The p o i n t to which the sap underccol-ed and the po i n t at which i t fr o z e were recorded. The i c e was then allow-ed to melt and enough f i n e l y ground succrose to make e x a c t l y a molal s o l u t i o n was added and d i s s o l v e d . Again the tube was placed i n the f r e e z i n g mixture and the point to which the s o l u -t i o n underdooledr and that at which i t fro z e were recorded. The exact amount of succrose to add i n each case was determined by c a l c u l a t i o n , given that 3.422 grams of succrose i n 10.000 grams of water gives a molal s o l u t i o n . The amount of water present In the sap i n each case was c a l c u l a t e d from the exact weight of sap used and the percentage of moisture of that p a r t -i c u l a r sample, which was determined by s u b t r a c t i n g the percent-19 . age• of t o t a l . B b l i d s readingr'fromllOO. VI. A n a l y t i c a l Methods. In 1941 a mineral a n a l y s i s was made of the ash of the tops of the 1937 tomatoes, s e r i e s 1 - 5 i n c l u s i v e . Tests were run f o r potassium, sodium, calcium, magnesium, phosphorus and sulphur. The ash of the .radish tops was analysed f o r potassium-only. Some tomato and r a d i s h seeds were analysed f o r potassium, ( l ) Making the HC1 Extract.' . The ash was placed i n evaporating dishes on a hot pl a t e and moistened w i t h d i s t i l l e d water. 3 cc. of concentrated C P . hydr o c h l o r i c a c i d was added and allowed to b o i l gently f o r a few minutes. Then a 10 cc. p o r t i o n of E/2 HC1 was added and.., when i t had b o i l e d p a r t l y away, another 10 cc. p o r t i o n of the IT/2 a c i d was added. A f t e r a few minutes of f u r t h e r b o i l i n g , t h e ' s o l u t i o n was decanted through a f i l t e r i n t o a 100 cc. graduate c o n t a i n i n g about 20 cc. of d i s t i l l e d water. In de-canting, the r e s i d u a l carbon and sand i n the s o l u t i o n was care-f u l l y r e t a i n e d i n the evaporating d i s h . This r e s i d u a l matter was extracted three more times w i t h 10 cc. l o t s of the l\f/2 HC1. The sand l e f t i n the evaporating d i s h was then d r i e d and weigh-ed to 0.001 gram. This was subtracted from the f i r s t ash weight to give the corrected ash weight. D i s t i l l e d water was added through the f i l t e r s to the s o l u t i o n In the graduates. "When the s o l u t i o n was c o o l , the volume was made up to 100 cc. f o r tomato s e r i e s 1 and 2, and to' 50 cc. f o r s e r i e s 3, 4, and 5. In the case of the radishes l e s s concentrated a,nd l e s s l / 2 I-IC1 was used and the volume was. made up to only 25 cc. 20 The a c i d e x t r a c t s were then poured i n t o convenient s i z e d b o t t l e s , w e l l stoppered, and placed i n the r e f r i g e r a t o r . 200 tomato seeds and 100 r a d i s h seeds were weighed, ashed, and ex-tr a c t e d w i t h H01 as above but using p r o p o r t i o n a t e l y smaller amounts of a c i d . The volume was made up to 10 cc. (2),Estimation of Potassium. The method used was -'that of S h e r r i l l (29) s l i g h t l y modi-f i e d . 10 cc. of the unknown was p i p e t t e d i n t o a 15 cc. gradu-ated tube. One drop of phenolphthalein was added. A concen-t r a t e d s o l u t i o n of IfeOH was added drop by drop t i l l the un-known was made a l k a l i n e , then g l a c i a l a c e t i c a c i d drop by drop t i l l the s o l u t i o n became c o l o r l e s s again. The volume was then made up to 12. cc. and the gelatinous p r e c i p i t a t e formed was f i l t e r e d o f f through a small f i l t e r . 10 cc, of the f i l t r a t e was added to 15 cc. of sodium c o b a l t i n i t r i t e i n a S h e r r i l l potash c e n t r i f u g e tube. 5 cc. of standard (15.83 grams of KOI per l i t e r ) were treated i n the same way. As 10 cc, of the standard' f i l t r a t e gave too heavy a p r e c i p i t a t e f o r comparison w i t h the unknown, only 1, 2, 3, or 4 cc. of t h i s were d i l u t e d to 10 cc. and then used. The p r e c i p i t a t e often tended to s t i c k to.the sides of the centr i f u g e tube' and i t was necessary to use a rubber policeman to remove-It. I t would then s e t t l e i n the narrow graduated stem a,s i t should. The tubes were then ce n t r i f u g e d f o r 5 minutes at step 20 on the centrifuge rheostat. A standard was always included i n each l o t of tubes put i n the ce n t r i f u g e . The-potassium was estimated by comparison w i t h the standard. (3) E s t i m a t i o n of Sodium. 21 The procedure followed was that, of Wall (53), A l l the t e s t s f o r s e r i e s 1, 2, 3, 4 and 5 were run at the same time, • In t h i s t e s t the sodium i s p r e c i p i t a t e d as the uranyl zinc acetate. The uranyl r a d i c a l i s then converted into uranyl potassium ferrocyanide. Phosphate i n t e r f e r e s and must he r e -moved. Calcium, magnesium, strontium, "barium, i r o n and potass-ium do not i n t e r f e r e . . Phosphate i s most s a t i s f a c t o r i l y removed by p r e c i p i t a t i o n as magnesium ammonium phosphate. Reagents. 1. Zinc uranyl acetate. 10 gm. uranyl acetate . i n . 50 cc. of "boiling water containing 2 cc. of g l a c i a l a c e t i c a c i d j and 30 gm. Zinc acetate i n 50 cc. of "boiling water con-t a i n i n g 1 cc. of g l a c i a l a c e t i c a c i d . Mix the "boiling s o l u -t i o n s , heat again to b o i l i n g and l e t stand overnight. F i l t e r ( i f there i s any sediment) and mix the f i l t r a t e w ith an equal volume of 9b% a l c o h o l . Let stand f o r 48 hours at 0° C. The reagent i s stable at room temper8.tu.re but i s best Icept i n dark-ness, 2, Magnesium n i t r a t e - 13 grams per l i t e r (magnesium c h l o r i d e - 10.5 l i t e r was used in s t e a d ) . 3. Concentrated ammon-ium hydroxide. 4. 9b% a l c o h o l . 5. 20%' potassium ferrocyanide. 0.1271 grams HaCI i n 100 cc. (lcc.=, 0.5 mg. Ha) was used as a standard. Procedure. 2cc. of ash s o l u t i o n was p i p e t t e d i n t o a. 15 cc, cen t r i f u g e tube. 2cc. of magnesium c h l o r i d e was added a.nd the tube was placed i n a, water bath and heated to 100° C. Then 2 cc. of concentrated ammonium hydroxide was added a.nd the tube was corked and l e t stand overnight. The tubes were then c e n t r i -fuged f o r 5 minutes at step 20 on the cent r i f u g e rheostat. A 2cc. a l i q u o t was p i p e t t e d i n t o another centrifuge tube, care 22 being.taken not to d i s t u r b the p r e c i p i t a t e of magnesium ammon-ium phosphate. The tubes were heated i n a b o i l i n g water bath f o r 15 - 20 minutes to dr i v e o f f the excess ammonia. The s o l -u t i o n was a c i d i f i e d w i t h 1 or 2 drops of g l a c i a l acetic' a c i d , and 4 cc. of the a l c o h o l i c z i n c uranyl acetate reagent was add-ed. The mixture was s t i r r e d or shaken t i l l p r e c i p i t a t i o n began A f t e r standing f o r one hour or longer, the tubes were c e n t r i -fuged f o r 5 minutes as before. The supernatant f l u i d was de-canted and the tubes were set upside down on f i l t e r paper to .drain. The mouth of the cen t r i f u g e tube was wiped w i t h f i l t e r paper. The p r e c i p i t a t e was then washed twice w i t h 5 cc. of 95% a l c o h o l , followed by c e n t r i f u g i n g and d r a i n i n g each time as before. The pr.ecipita.te was d i s s o l v e d i n water and t r a n s f e r r e d to a 100 cc. graduate. 4 drops of g l a c i a l a c e t i c a c i d a.nd 2 cc (6 drops i s s u f f i c i e n t ) of potassium ferrocyanide reagent was added and the s o l u t i o n was made up to volume-,' The. s o l u t i o n s were w e l l s t i r r e d and compared wi t h a. sta.nda.rd containing 0,5 mg. of sodium. 1 cc, of standard was treated as the unknowns from the point of a c i d i f y i n g w i t h a c e t i c a c i d and a.dding the a l c o h o l i c zinc uranyl acetate. When the a l c o h o l i c z i n c uranyl.acetate i s added to the un-known the a l c o h o l may p r e c i p i t a t e some ammonium and magnesium salts.- These do not a f f e c t the determination and are ea.siEy soluble i n water. (4) E s t i m a t i o n of Calcium. The method used was s i m i l a r to that used by Wall (33) and i s based on that of McCance and Shipp (18). This element was determined by p r e c i p i t a t i o n as the oxalate and t i t r a t i o n of the 23 l a t t e r w i t h potassium permanganate. 5 cc. of the ash s o l u t i o n were p i p e t t e d i n t o a 15 cc. graduated centrifuge tube. 0.2 cc. of a 0.02^ s o l u t i o n of phenol red was added and a concentrated s o l u t i o n of ammonia was slowly run i n with constant shaking or s t i r r i n g t i l l the c o l o r changed from orange through yellow to p u r p l i s h red. This ammonia should be of such a strength that l e s s than 0.6 cc. of i t i s required to n e u t r a l i z e the s o l u t i o n . Next j u s t enough g l a c i a l a c e t i c was added drop by drop, with shaking, to make the s o l u t i o n b r i g h t yellow. • Water was run i n . to' b r i n g the t o t a l volume up to 6.5 cc. Then 1.5 cc. of a saturated s o l u t i o n of ammonium oxalate were added to p r e c i p -i t a t e the calcium. Thus 5 cc. were d i l u t e d to 8 cc. The mix-ture was allowed to stand f o r 1 hour and then centrifuged f o r 5 minutes at step 20 on the c e n t r i f u g e rheostat. The super-natant f l u i d was poured o f f i n t o a clean t e s t tube and kept (corked) f o r the estimation of magnesium. The p r e c i p i t a t e was drained and washed w i t h 5 cc. of 1% ammonia. The mixture was then c e n t r i f u g e d again, decanted and drained. To the washed residue i n the c e n t r i f u g e tube 1 cc. or more of 4 N sulphuric a c i d was axlded, and the tube was placed i n a b o i l i n g water bath f o r a few minutes. When the p r e c i p i t a t e was d i s s o l v e d the s o l u t i o n was t r a n s f e r r e d to a small beaker or small f l a s k . The tube was r i n s e d and the r i n s i n g s were added to the beaker. The beakers were set on a hot p l a t e and the s o l u t i o n was t i t r a t e d while hot w i t h potassium permanganate. The normality of the permanganate was near N/50 i n the one case and near N/lOO i n the other. . In each case the permanganate was standardized w i t h sodium oxalate j u s t before t i t r a t i n g the unknowns. The t i t r a -24 t i o n was c a r r i e d to a f a i n t pink end p o i n t . The end point was quite sharp* (-.one drop made the d i f f e r e n c e ) and quite permanent. Tests on s e r i e s 1 and 2 were run at one time and on s e r i e s 3, 4 and 5 at another time. '• . (5) E s t i m a t i o n of Magnesium. 0.3 cc. of the supernatant l i q u i d from the calcium estim-a t i o n were p i p e t t e d i n t o a 15 cc. graduated centrifuge tube and d i l u t e d to 4 cc. 1 cc. of 2%> ammonium phosphate and 2 cc. of concentrated ammonia were added, and the mixture, a f t e r "being shaken was l e f t to stand overnight. The tubes were then c e n t r i -fuged f o r 7 minutes, drained and washed w i t h 5 cc. of 10% ammonia, r e c e n t r i f u g e d and drained i n the usual'way. The pre-c i p i t a t e was next d r i e d by p l a c i n g the centrifuge tube i n a b o i l i n g water bath. To the magnesium phosphate ( p r e c i p i t a t e ) 1 cc. of IT/10 h y d r o c h l o r i c a c i d was added and 5 cc. of water. Care was taken at t h i s p o i n t to ensure that the p r e c i p i t a t e . h a d a l l gone in t o s o l u t i o n before proceeding to the next stage. Eor the standard, 1 cc. of a s o l u t i o n of potassium di-hydrogen phosphate c o n t a i n i n g 0.1 mg. of phosphorus per cc. was placed i n a t e s t tube together w i t h 1 cc. of l / l O HC1 and 4 cc. of water. To a l l tubes was then added 1 cc. of Deniges ammonium molybdate, followed by 0.5 cc. of 20% sodium s u l p h i t e , and 0.5 cc. of f r e s h l y prepared "0,2% hydro qui none. The contents of the tubes were mixed, allowed to stand f o r h a l f an hour and then matched i n the colo r i m e t e r . This procedure was found by t e s t w i t h known amounts of magnesium to give a s l i g h t l y high value, but since i n t h i s experiment r e l a t i v e , not absolute r e s u l t s were r e q u i r e d , t h i s s l i g h t l y h i g h value d i d no't: seriously,, a f f e c t 25 the r e s u l t . Series 1 and 2 were run i n one l o t and se r i e s 3, 4 and 5 i n -one l o t . (6) Estimation of Phosphorus. The procedure followed was as that f o r magnesium from the poi n t where the magnesium has "been p r e c i p i t a t e d as magnesium phosphate and then d i s s o l v e d . E i r s t though, 1 cc. of the unknown was p i p e t t e d i n t o a graduated tube. One drop of phen-o l p h t h a l e i n was added, followed by enough HaOH to make a l k a -line,-, and then enough g l a c i a l a c e t i c a c i d to render the solu -t i o n c o l o r l e s s again. "The volume was ma.de up to 5 cc. The prepara t i o n "of the standard and the a d d i t i o n of the reagents to develop c o l o r was done as under 'Estimation of Magnesium' from the point mentioned. (7 ) Estima t i o n of Sulphur. The method used was based on that of Richards and Wells (27) 5 cc. of unknown i n a graduated tube was placed i n a b o i l i n g water bath. Once i t s temperature had r i s e n to near 100°C. 5 cc. of a 2% s o l u t i o n of barium c h l o r i d e was added. Heating was continued f o r a few minutes and the volume was made up to 10 cc. 5 cc. of a standard c o n t a i n i n g 1000 p.p.m. (5 mg.) of SO4 was trea t e d i n the same way. Sulphur was estimated by comparison w i t h the standard i n b l a c k bottom cups i n the colorimeter. V I I . Further T r a n s p i r a t i o n Tests. Since i n d i v i d u a l tomato p l a n t s w i t h i n each s e r i e s showed considerable v a r i a t i o n i n t r a n s p i r a t i o n r a t e , f u r t h e r measure-ments were attempted i n the greenhouse during the l a t e f a l l and e a r l y winter of 1940. F i r s t a number of shoots were taken from two l a r g e p l a n t s and placed i n water. Some others were placed 26 i n moist sand. Although tomato shoots are supposed to root quite readi-ly i n water or moist sand, these d i d not. Had these shoots rooted i t might have "been po s s i b l e to show whether or not the great v a r i a t i o n i n t r a n s p i r a t i o n rate w i t h i n a nu t r i e n t s e r i e s was due to heredity. Next twelve small tomato plants growing i n a f l a t of s o i l were transplanted to dark water culture j a r s . The roots were washed f r e e of s o i l and each plant was weighed to 0.1 gram before t r a n s p l a n t i n g . The pl a n t s were set i n cork stoppers and the space between the stem and the cork was f i l l e d w i t h parawax. The p l a n t s were l e f t i n tap water one week a.nd the water l o s s was measured each one or two days. One week l a t e r the weight of the plant s was again taken as f o l l o w s . The t o t a l .weight ( j a r + water, p l a n t , cork + wax +• water adhering to i t and to the plan t roots) was recorded. The plan t w i t h the cork was t r a n s f e r r e d to another j a r of water, and the j a r f water was weighed. Then, since the weight of the cork •}• wax + water adhering to i t and to the plan t roots was already known from when the experiment was set up, i t was pos s i b l e to c a l c u l a t e the weight of the p l a n t . The p l a n t s were p a i r e d o f f , those having nearly the same t r a n s p i r a t i o n r a t e s being together, and the d i f f e r e n t i a l nut-r i e n t treatment was begun, one plant of each p a i r r e c e i v i n g f u l l n u t r i e n t and the other potassium d e f i c i e n t c u l t u r e s o l -u t i o n s . T r a n s p i r a t i o n losses were recorded f o r a few da.ys more, but then due to several nights of low temperature, lack of a e r a t i o n 'of the r o o t s , and p o s s i b l y to the fungus growth on the r o o t s , the pl a n t s s t a r t e d to lose weight a.nd d e c l i n e . The 27 cu l t u r e s were kept going f o r some time longer "but the plants f a i l e d to recover and the experiment was discontinued. RESULTS Z.' General Appear a, nee of the P l a n t s . In general appearance the f u l l n u t r i e n t p l a n t s and the pot-assium d e f i c i e n t ones were very much the same? the potassium d e f i c i e n t p l a n t s being j u s t as healthy as the f u l l n u t r i e n t ones i n the case of both radishes and tomatoes. This s i m i l a r -i t y i s shown i n the photographs appended to t h i s pa,per. The leaves of some of the r a d i s h p l a n t s i n each s e r i e s were damaged by slugs. The f o l l o w i n g observations r e f e r to the 1937 tomatoes at the time of c u t t i n g . The f u l l n u t r i e n t a,nd potassium d e f i c i e n t plants, both had good c o l o r . At the time of c u t t i n g , a l l the p l a n t s i n these two s e r i e s ( l and 2) were i n blossom and the second c l u s t e r of blossoms was forming. F r u i t s were j u s t form-ing i n some of the f u l l n u t r i e n t p l a n t s . As none of these tomatoes were i n a.ny way pruned, a l l these plants ( s e r i e s 1 and 2) had two or three w e l l developed shoots a r i s i n g from the a x i l s of the f i r s t leaves. Series 5 also received f u l l n u t r i e n t treatment but was l e f t i n the shallow f l a t and only t r a n s p l a n t -ed .from i t to smaller ca,ns two weeks l a t e r than was s e r i e s 1. These p l a n t s had good c o l o r but were not- so b i g as those trans-planted to the la.rge cans. These plan t s were not i n f u l l blossom as were those of s e r i e s 1, and the secondary shoots were only a l i t t l e developed. The p l a n t s d e f i c i e n t i n phosphorus, s e r i e s 3 and 4, were quite d i f f e r e n t i n appearance. These plan t s were smaller than 28 those of s e r i e s 5 , and much smaller than those of s e r i e s 1 and 2. The plant s of s e r i e s 3 were the smallest. The blossoms and secondary shoots were s l i g h t l y more developed than those of ser i e s 5 , s e r i e s 4 having some blossoms open. I t i s seen that the plants of s e r i e s 4 were a l i t t l e bigger and more developed than those of s e r i e s 3. This might be because they had been i n a l e s s crowded and a much deeper f l a t . The l e a f l e t s i n ser-i e s 3 and 4 were smaller and of a more ye l l o w i s h green color than those i n s e r i e s 1, 2, and 5. The l e a f l e t s were also some-what c u r l e d , and showed a l i g h t p u r p l i s h c o l o r i n the under side; s e r i e s 4 showing a s l i g h t l y deeper p u r p l i s h t i n t than s e r i e s 3. The lowermost leaves i n these p l a n t s ( s e r i e s 3 and 4) were turning, y e l l o w i s h and had p a r t l y decayed brownish areas. The roots of these p l a n t s were darker and l e s s healthy looking than those of s e r i e s 1 and 2. In s e r i e s 6 and 7 the new leaves were of good s i z e and c o l o r , s i m i l a r to those of s e r i e s 1 and 2. Nevertheless the pl a n t s were much smaller and had not formed blossoms, .though one p l a n t i n s e r i e s 6 had blossom buds. In most p l a n t s , secondary shoots had formed i n the a x i l s of the f i r s t leaves. These f i r s t leaves had improved i n color but only very l i t t l e i n s i z e since the change to n u t r i e n t s o l u t i o n s containing phos-phorus. On the whole, s e r i e s 6 made more recovery than d i d s e r i e s 7 from the e f f e c t s of the phosphorus d e f i c i e n c y . I I . A n a l y s i s of Seeds. 200 tomato seeds were found to average 3.5 mg. i n weight, and to contain 0.024 mg. of potassium ( i . e . 0.69^ K) per seed, while 200 r a d i s h seeds averaged 9.9 mg. i n weight and contained 0.071 mg. of potassium ( i . e . p.72 % K) per seed. Table I I I A. Height of Tops; Fresh and . Dry Weight, Per Cent Moisture, and Per Cent Dry Matter of Roots of a l l Series of Tomatoes and Radishes. CM co PH • o EH s; p=t o E-f 03 EH O EH H H H •2 aS EH I PH MM FH sf I I fzj P4 to P=H 1 O lO to 03 o • • H <0 rH o to in CM O to sf to to CM CM H O LO CO sf CM o •si 1 tO sf H sf H CD o sf to to H to to CD to CO to 03 to CM to H o o CO to o CO sf LO H -p a a) a) a) f-i EH SH (D CO a) u 3 CQ Cli • o ;S tO CM CO C\i 01 co OJ rH rH CM CO CD 03 CO to to H CO 03 H CM H sf CM" CM to to CO to CD CD to ID • • • • CO o o O " 0! to t> CD O Sf • • • • CD rH O O H CM to CQ H O to , to CD !> tO lO O C\) tQ O rH CM sf sf to H O O CD to o o co sf o o o rH • • to to o K O sf CD CD CD o z> sf CM' to 1 10 1 o> to cv to o 03 to to H O to • • CO CD o to rH to st" CM to H CO rH o o to 0! co sf to CO • t» H O o rH to CO o r-sf sf sf rH H 03 to o CO CM to CO 1 1 O rH to 1 CD to 1 sf to to CD to to 03 CO in to to to to co sf co CT> CM H to o LQ tO CD CD CO to CD CD O 03 sf to tO to o to Sf rH CD to • « • • Z> CD • • • * to to o OJ o 03 CD CD CD to . 03 to co t> e. • to to o 03 o 03 CD CD CD -sf CM CD CD in 03 t> to 03 • • • • CD tO H 03 03 CD CD CD CO CM B K a •H u CM I> lO CD £- CO O) LO to • • • CD tO CO o sf a a o •rH -P a •H (H o o CD C0 o o o sf CM O CD CD to CO O H O rH CD CD CD 60 a as td ri =1 •P "H CD CD 03 tO o o O CD CD CD tO 03 CO H O O CD CD CD 0 bO a Si CD rt H^ m . m •H CQ -p O -P o O o O K "el K o o O LO CD to co in o co CO CD 03 to LO to 03 ID CD CO oi r- co f> LO CO in to to co -co i> sf CM ^f • • • CD !> CO CM t- O CD CO CD CO H CD CD CO CD CO sf CD CD a! SH CD CD HJ si cc u O -r-\ 3* . Ai © - — ^ > AH 4* 2 -H 01 a? +J id i>- & a i> —-'2 •— & g i^J 43 T3 TO <^ 0) o Xi CQ C5 a " ; u 10 I -P ifl a> 3d Si ^ JH to i' a>, -a o o AH U S S ® ^ ^ O -r-4 O O >H o o -H a ^ •H Vl P| P •p In a) a d a> a r4 a) A ,.q 'H ^ g ? H 2 -H O CD ^ +3 f?EJ , o P o d o PH O CQ O r4 PH PH , Table.. I l l B. ..Fresh Weight of Tops, Per Gent Leaf i n Tops-, and T r a n s p i r a t i o n i n a l l Series of Tomatoes and Ladishes. £5 PH M -C- LO I 1 PH is. I [if MM PH c-i I S P4 w o • H M i S3 ft u 3 -p S3 05 r-i PH CO a> COW in to *^ IO CO to H to io to to O to to H . C7> r-t- tO j> to CO J> CNI H to CO o> to CJ> to CNJ to CNJ CNJ ^< -* CNJ to *H< o » • • • • to to to o CNI •St 1 H ^ "H< t-« • o to to o> to to to >rf< to CO r-i o to to to C\)'tO « CNJ to ^ CO at to i> CNJ m CO to c- to o £> in in • o o CNJ • in in I—1 rH to rH' in H o » NO o to co • o to CO ON to to to H CO • m o co to • co e> to CNJ to w to H tO E> •* to to CNJ CO H in to to co' o to CNJ to to to tO CNJ c-to ON CNJ H a •H S3 O •H -P 0) bp • «5 S3 W) -H K • < oj > in * • to o to CNJ to to CNJ to I* a> a> co in o> to to CNJ CNJ H CNJ :tO • O o . to m tO H co in CO H r-i in to to I-i CO CO B -tf CO c-H • CO B H ON CO 1-1 CO • o ON * to • • CO H to . • CO E- CNJ CNJ CNJ rH p o E-t 0 u o tH 03 •p CO a Hi CO CO ' m co j> ON co m % r-i • B CO NO B CO H in c-!> H I I I I I I I I S3 trj H p o H I I l I o tH MH 0 s CD hO S3 03 P3 60 o S3 H MH +3 S3 tH tH a) to CNJ m in co CNJ to CNJ CNJ CNJ o ^i in a> CN! CO to • co to . H r-i CO H •sji in CNJ o CNJ CO CNJ c- in to CNJ CNJ CNJ CNJ rH O J> CNJ r-i O CO CNJ H O £> CNJ H <» 05 ho H S3 a> cS n !> P3 CO S3 S3 o •H -H •P P cS cS 54 ^1 •H •P Pf (Q o S3 -p a H (U EH -d oS o ^3 •H CO -P 03 a •H 60 S3 tr) (H H S SH o S3 •d S3 o >> . tD ^3 H 05 tH H -P K tu ^3 CD H 03 !> CD H -P S3 •H H O M SH tu I Table IV. .Dry Weight, Per Cent Moistures Per Cent Dry Matter, 'Ash Weight, and Per Cent Ash i n Dry Weight of Tops of a l l Series of Tomatoes and Radishes. -ft l I 1 ft B to • ' CM ft KM ft ft i CNI -HJ ft -P a u EH H 1) CO TH. CD H CO (d tt> a B H ft O H CD a rH r-i t£) OI r-i iH to C\2 o 01 to H rH rH CO oi CO OI o o 0 to 01 CO CO CO CO CO CO ON co o to CNI rH rH ON r-i tf1 to CO CO ON to w to t> CNI C--ON • • S1 H CM to CO to CV o CN! rH CC rH o> CO r-i ' oi o> ON en >H< CO ON *H< H oi ON OV ON CO to D-H r-i H o> o> ON OI ^F CO H CO ON D-O CO rH CO ON to O ON ON 00 o o o ON ON ON -Ht r-i KF CO c- to CO CN] to bo a tri p o EH •P N •p H CH O co CO CO O ON ON CO CNJ to CO rH to r-i • • • * ON ON ON CO rH co co CO 60 cS bo cS U CD 4 p O EH CO O CO C to «D ^ r-i ON CNI o CO to £> C\! to co to •31 CNJ CO CO O ON rH O to o Oi to CO ON CNJ a> H to ^ H O co ON O ON ON CM • • o o M a ID bo u is p o EH u CD -P Si SI to CO CO 01 CNJ H rH CO OJ OI r-i CO CO tF H O o a> z> co CO CNJ co co ON CNJ to to to o tO CNJ c- CO to to tO %F OJ to to OI CO ON rH rH rH tO £> t> OI ON O rH rH o to •sF !>• rH CO O CNI to OJ rH t I I I I I I i o to o tF CO H CNI rH CNI ON CO CNJ CO ON CNI OJ H CNI rH ON O co z> co rH r-i H co to 01 co c-CO H H rH C- ON ON ON £> CO r-i H . rH to to tO KF O CNJ HH rH CNJ O ON CO CNI CNJ r-i rH rH bO bO a K J-t SI 1^ CO 40 4.7 5.1 3,9 4.6 4.8 o«5 — -4.65 4.95 3.7 3,9 1,5 4.3 7.6 3-5 4-3 4-5-< 5% >10^ <5fo ! RADISH *Extreme value - beyond normal range. ^ Range Moist. 95.9 95.4 96,2 95,3 j 1 95.4 ! 95.3 95.2 94.9 96,5 96.1 -- --Avg, 95.6 95, 6 95.4 , i 95.0 96,3 95.4 96.1 Range 'Resistance i n ohms Avg. Coef, of Var. i n % 14.1 13,8 14,0 1 o 1 17.8"^ 16,0 14.7 15.7 11^7 12.1 ! 4.7 12.0 11,3 11.6 4.2 14.7 15'. 0 2.8 11.3 11.7 S i g n i f i c a n c e 2 — -- <1 - i % 5-3 3-4 >40% 5-4 < 2% Range Osmotic Pressure i n atm, Avg. Coef. of Var. i n %. 6.14 5.30 5.66 5 « S 6.14 5.54 4.46* 5.54 10.3 6,63 5. 65 6.15 11.0 5.67 5,30 5.48 4.8 4.28 4.82 4.82 1 6.27 5,90 S i g n i f icance 1 -->60 2 1 3-5 >10% 3-4 >20% 4-5 Table . VI 36 Mineral Analysis Data Treatment TOMATOES RADISH F.N, K F.N. P.N. s % P Range i n Ash Avg. 1. 89 2.01 2.26 2.03 2.18 0.78 0,66 0.74 0,73 0.65 0.69 1.61 Coef. Var. % 7.1 5 • [3 7.9 6,0 _ ^ S Range i n Ash Avg. Coef. Var. % 3.94 4.48 1.43 1.04 _ 3.08 3.45 1.09 0.94 1.86 3. 63 3.95 1 © 21 1.00 10.4 14.7 14.4 5.9 — Series No. of Plan t s 1 1 2 4 4 - P -PK 3 4 5 j 1 2 3 3 2 ' 1 4 4 % K Range i n Ash Avg, .Coef. Var. - % 26.9 17.7 23,6 15,3 24,6 16.0 6.4 6.9 15.5 12,6 30.3 a I..13v2 6.1 11.5 9,0 15,0 b j 9,3 1.3 13.6 10,6 - j-11.3 4.1 1 4-7 17.0 - j 14.8 45.4 Na Range In Ash Avg. Coef. Var. % 3.15 2.88 2.15 2.06 2.64 2.45 18.4 4.8 3.47 3,23 2.84 2.65 3,79 b 3.18 2.85 10.0 11.4 i — I I % Ca Range 15.7 19.5 i n j 13.7 16.0 Ash Avg. j 14.6 18.0 Coef. Var. % j 6.6 8.2 • l 24.9 24.5 16.1 b 20.2 22.3 12.6 a 22,7 ' 23.1 10.4- 5.2 _ - ! i % Mg Range 1 6.09 7,97 8.70 7,46 6.9? a ™ K f 4 « 5 7 6.54 j 6.10 3.84. 5.03 b Ash Avg. 15.47 7.30 j 7,07 5.72 Coef. Var. % | 12.2 10.3 j 20.1 31,8 - 1 -37 The s i g n i f i c a n c e recorded i n tables V and VII i s the s t a t -: i s t i c a l s i g n i f i c a n c e of the di f f e r e n c e of the means expressed as p r o b a b i l i t y i n per cent. " I f the p r o b a b i l i t y i s very small the assumption can be s a f e l y made that the samples do not be-long to the same population, i . e . , that there i s some fund-. amental d i f f e r e n c e between the v a r i a b l e s . " (25) A p r o b a b i l i t y of l e s s than 5 % i s u s u a l l y considered s i g n i f i c a n t , while one of l e s s than 1 % i s considered h i g h l y s i g n i f i c a n t . The s t a t i s -t i c a l c a l c u l a t i o n s here recorded were made according to the methods of Paterson (25) which are based on those of Pisher of Rothamstead. I t i s shown i n table VI - Mineral a n a l y s i s data - that the potassium d e f i c i e n t p l a n t s contained a. f a i r amount of potassium. Another poin t of i n t e r e s t i s that the plan t s which received no sodium i n the n u t r i e n t s o l u t i o n had, as great a percentage of sodium i n the ash as d i d those which received the sodium. The d e f i c i e n t s e r i e s , 2, 3 and 4, showed a higher percentage of both calcium and magnesium i n the ash than d i d the c o n t r o l s e r i e s , 1. Only two p l a n t s of s e r i e s 5, the small f u l l n u t r i e n t c o n t r o l s , were analysed, and as one of these (b) showed the ash character-i s t i c s of s e r i e s 2 ( - K) while the other (a) showed the char-a c t e r i s t i c s of s e r i e s 1 (F.N.) the r e s u l t s were not averaged, but reported separately. P l a n t (a) t r a n s p i r e d as d i d those .of s e r i e s 1, while pl a n t (b) wi t h only h a l f the percentage of potassium i n the ash t r a n s p i r e d as d i d the plant s of ser i e s 2, which had a s i m i l a r low percentage of potassium. 38 R e l a t i v e Differences and S i g n i f i c a n c e TOMATOES RADISH Series F N - K AB 0 F N - K 1 2 F N - K FNs - P -PK 3 4 5 - P -PK F N - K 6 . 7 F N - K . 1 2 Wt. Rts. Fresh S i g n i f , 100 127 C -- AB > 20 % 4 — — 100 105 2 1 >40 % 50 72 100 5-3 4-3 5-4. ,5^ >5^ 100 29 6 -- 7 < 1 % 100 92 1 -- 2 > 40 # Wt. Rts. Dry S i g n i f . 100 118 C — AB >50 % 100 102 2 -- 1 >50 % 58 . 83 100 5-3 4-3 5-4 100 36 6 — 7 O erf ~fC /o 100 89 . 1 2 "> 20 % Wt. Top Fresh S i g n i f . 100 122 C -.- AB >10 % 100 91 1 2 <1 % 51 68 100 5-3 4-3 5-4 <1% >1Q% <5fo_ 100 30 6 -- 7 <1 % 100 109 2 1 > 50 % a. •Leaf S i g n i f . --100 104 2 — 1 <5 % 112 104 100 3-5 3-4 4-5 <1% <5% y\o% 100 104 7 -- 6 >10 % Wt. Top Dry S i g n i f . 100 119 C — AB >40 % 100 86 1 — 2 > < 5 % 60 87 100 5-3 4-3 5-4 >10^ > 7>0% >40^ 1 100 30 j 6 7 < 1 % 100 1 0 0 " 1 2 > 90 ^ Transp, 100 gm. • Top S i g n i f . 100 117 C — AB <5 % 121* 100 114 2 1 <5 ' i 54 44 100 5-3 3-4 5-4 < i i > 53 10 % 100 99 1 -- 2 )70 <% Transp. 100 gm. Leaf S i g n i f . — 100 108 2 -- 1 >20 % .<2 5 % -Ash Wt. Tops - 100 83 62 88 100 j 1 0 0 28 100 104 39 Table' V I I R e l a t i v e Differences and S i g n i f i c a n c e TOMATOES RADISH Treatment Series P IT - K ' 1 2 E IT - K PHs - P -PK 3 4' 5 - P -PK P IT - K 6 7 ,. P H - K 1 2 % Ash.In Dry Wt. 100 ' 98 146 142 140 172 163 100 105 ' % K i n Ash 'Significance 100 65 1 — 2 <1 % 56 43 122 a 61 b 3-4 1-3 2-4 >1Q% 40 % 121 108 144 b 3-4 3-1 4-2 >20^ >40/ >5/ -•% Ca i n Ash S i g n i f i c a n c e 100 124 2 — 1 156 ' 159 87 a 111 b 4-3 3,-1 4-2 >80/ 30^ >io;€ >20% - - - . % P i n Ash S i g n i f icance 100 108 2 -- 1 > 10' % 36 34 80 b 3-4 1-3 2-4 -)50% <\% <1% ---% S i n Ash S i g n i f i c a n c e | 1 100 109 2 — 1 >30 33 28 51 b 3-4 1-3 2-4 >10^ <1< T. ) i s s i g -n i f i c a n t l y greater than that of s e r i e s 2 (- K) i n the tomatoes, while the per cent l e a f e,nd t r a n s p i r a t i o n are s i g n i f i c a n t l y greater f o r s e r i e s 2. In the ca.se of s e r i e s 3 (- P) and se r i e s 4 •(- PK) the only s i g n i f i c a n t d i f f e r e n c e i s that of per cent l e a f , i n which the value f o r s e r i e s 3 i s the greater. In many cases, one or both of these s e r i e s (3 and 4) d i f f e r e d from the c o n t r o l s e r i e s , 5 (P.N.s). I t should be noted that they (3 and 4) weighed less•a n d ' t r a n s p i r e d l e s s , per u n i t of weight, than t h e i r c o n t r o l , s e r i e s 5. The recovery s e r i e s , 6 and 7, showed a. s i g n i f i c a n t d i f f e r e n c e i n weight but not i n t r a n s p i r a t i o n , though the t r a n s p i r a t i o n per u n i t of weight was greater f o r se r i e s 7, the potassium d e f i c i e n t one. 41 In regard to the ash a n a l y s i s of the tomatoes, s e r i e s 2 " ' (-.K) showed a s i g n i f i c a n t l y greater percentage of calcium and magnesium, and a greater, hut not s i g n i f i c a n t l y greater , percentage of phosphorus and sulphur. Sodium i s the only case where no s i g n i f i c a n t d i f f e r e n c e s appeared i n any s e r i e s . Series 3 (- P) and s e r i e s 4 (- PK) were not s i g n i f i c a n t l y d i f f e r e n t i n percentage of any element i n the ash, hut were s i g n i f i c a n t l y l e s s i n per cent potassium than se r i e s 1 (P.IT. ) and s e r i e s 2 (- K) r e s p e c t i v e l y , and greater i n per cent calcium, IV. The Further T r a n s p i r a t i o n Tests. Although t h i s experiment was discontinued, because the pl a n t s f a i l e d ' to recover from the e f f e c t s of too low green-house night temperatures, the growth'and t r a n s p i r a t i o n during the f i r s t week i n tap water show considerable v a r i a t i o n from pl a n t to p l a n t . The c o e f f i c i e n t of v a r i a t i o n of the d a i l y t r a n s p i r a t i o n of 12 p l a n t s was 13.5 $, 18.6 and 19.3 €. The f i g u r e s f o r per cent increa.se i n growth (weight) during the same week averaged 14.1 %, wit h a range of 8.9 % to 22.6 and a c o e f f i c i e n t of 28.8 When plant s with near the same t r a n s p i r a t i o n rate were paired o f f , and the one placed i n f u l l n u t r i e n t c u l t u r e s o l u t i o n , while the other one was placed i n potassium d e f i c i e n t c u l t u r e s o l u t i o n , the s i g n i f i c a n c e of the di f f e r e n c e i n t r a n s p i r a t i o n f o r the f i r s t day was between the 50 % and the 60 % p r o b a b i l i t y l e v e l s , i . e . , not s i g n i f i c a n t . 42 DISCUSSION A number of workers now agree that there i s an abnormal water requirement i n at l e a s t some potassium d e f i c i e n t p l a n t s . Unfortunately reports of a c t u a l measurements of this, excess t r a n s p i r a t i o n a l water l o s s are scarce. The r e s u l t s of the experiments reported i n t h i s paper show f a i r l y c o n c l u s i v e l y that tomato, hut not r a d i s h p l a n t s , lose more water through t r a n s p i r a t i o n when they are d e f i c i e n t i n potassium than when they are normal or when d e f i c i e n t i n phosphorus. Some confirmation of.these r e s u l t s i s seen i n the reports of the f o l l o w i n g workers. Morse (22)/in r e p o r t i n g experiments on soybeans.and m i l l e t grown i n pots of s o i l w i t h , and without added potash,•and at three water l e v e l s , wrote "Of these pot experiments i t can be s a i d that the presence of potash increas-ed the e f f i c i e n c y of the l i m i t e d supply of water i n developing the p l a n t s . " Morse also r e f e r r e d to the b e n e f i c i a l e f f e c t s of potash f e r t i l i z e r s i n dry seasons as mentioned by H a l l (7) i n h i s d e s c r i p t i o n of the Rothamstead experiments. This work of Morse confirms the work of Maercker (17) already mentioned (pages 3-4). He found that the favorable e f f e c t of potash on water economy was more pronounced i n the s o i l containing the smaller percentage of i t s water capacity. Tincker and Da r b i s h i r e (32) i n t h e i r work on Stachys tuber-i f e r a (as already mentioned - page l ) noted w i l t i n g of a l l the potassium d e f i c i e n t p l a n t s at the end of a hot day, whereas comparable p l a n t s supplied w i t h potash remained erect and t u r g i d , Hartt (9), too, i n her work on sugar cane noted a somewhat s i m i l a r case. P l a n t s r e c e i v i n g about h a l f the f u l l 43 amount of potassium required considerably more water than p l a n t s , with the f u l l amount of potassium, which were apprec-i a b l y l a r g e r i n s i z e . The r e s u l t s given i n t h i s paper are also i n accord with those of Reed (26), Hansteen-Cranner (8) and Kisser (14) already mentioned (pages 5-6), but not w i t h those of Childers and. Cowart (3). E c k s t e i n , Bruno and Turrentine summarising the r e s u l t s of other workers i n "Potash D e f i c i e n c y Symptoms" (5) have the • f o l l o w i n g to say i n t h i s matter. "The unfavorable influence of potash d e f i c i e n c y on the water r e l a t i o n s h i p s of our c u l t i v -ated p l a n t s , which i s due to an impairment of water absorption and e s p e c i a l l y to an increased emission of water, also decreases the a b i l i t y of the plant to withstand drought. This unfavorable influence of potash d e f i c i e n c y i s manifest on hot days and at noon, ..... Experiments on meadows have also f r e q u e n t l y shown that i n dry years the potash d e f i c i e n t p l o t s are the f i r s t to s u f f e r from drought." And also t h i s "Potash d e f i c i e n c y exerts an unfavorable influence on the water u t i l i z -a t i o n of the p l a n t . A l a r g e r amount of water i s necessary to produce one gram of dry matter when potash i s d e f i c i e n t than when i t i s abundantly supplied. The r e l a t i o n s h i p s between t r a n s p i r a t i o n and potash n u t r i t i o n are the biggest f a c t o r s i n the impairment of the water economy of the pl a n t when potash i s d e f i c i e n t . The potassium i o n tends to reduce t r a n s p i r a t i o n . In the case of a l a c k of potash the water l o s s i s greater, and w i l t i n g , t y p i c a l of potash s t a r v a t i o n , r e s u l t s . " Cowie i n the same book (5) deals with the r e l a t i o n of 44 po t a s s i u m t o "Leaf Scorch", and r e f e r s to the work of Wallace (34) and HOblyn ( l l ) on t h i s point. " 'Leaf Scorch' ...occurs under conditions which a f f e c t the tree i n such a way that the amount of water t r a n s p i r e d from the leaves i s greater than the amount absorbed by the roots. The r e s u l t of t h i s c o n d ition i s that the c e l l s round the margins of the leaves are k i l l e d , producing t y p i c a l scorched leaves, with a reduction of the t r a n s p i r i n g surface. Experiments i n commercial orchards have shown that 'Leaf Scorch' may occur on any s o i l where the potash supply i s inadequate f o r the needs of the tree . ...... 'Leaf Scorch' can also be produced by the continuous use of f e r t i l -i z e r s containing no potash. ..... 'Leaf Scorch' becomes most marked i n hot dry summers. ..... An important point which has emerged from the chemical i n v e s t i g a t i o n s r e l a t i n g to 'Leaf Scorch' i s that i n a l l cases examined i n the- f i e l d the scorched tree i s a low-potash tree and Is a.pparantly s u f f e r i n g from a d e f i c i e n c y of t h i s element." In o p p o s i t i o n to the genera.l agreement w i t h the r e s u l t s reported i n t h i s paper i s the work of Snow (30). In work on sunflower, toba,cco and bean plants i n s o l u t i o n c u l t u r e s , he found that the t r a n s p i r a t i o n of plaints i n potassium d e f i c i e n t c u l t u r e s o l u t i o n s decreased a f t e r a time as compared wi t h the c o n t r o l s i n f u l l n u t r i e n t s o l u t i o n s . However i t should be noted that whereas h i s p l a n t s were completely d e f i c i e n t i n potassium the pl a n t s i n t h i s experiment were only p a r t i a l l y de-f i c i e n t i n potassium as seen by the r e s u l t s of the a.sh a n a l y s i s . Confirmation, i n larg e p a r t , of the r e s u l t s of the mineral a n a l y s i s i s also found i n the reports of other workers. Colbjr (4) working on French prune tr e e s , and Johnston and Hoagland (13) working on tomatoes found low potassium content of the ash associated w i t h higher calcium, magnesium and phosphorus con-tent as compared w i t h a higher potassium content of the plant ash. Fonder (6) working on a l f a l f a also found the lower potassium content associated with the higher calcium content of the-plant. This was- the case i n the experiments here reported, except that the d i f f e r e n c e i n the case of phosphorus was not s i g n i f i c a n t . The work of Il a r t t (9) on sugar cane also supports t h i s , i n that w i t h a medium, as compared to a high, suppljr of potassium there was an increa.se of per cent calcium, magnesium, and phosphorus i n the bla.des, hut w i t h the lowest supply of potassium the calcium and magnesium percentages were lower than i n the case of the medium supply. /This suggests that i n regard to a potassium d e f i c i e n c y the degree of s t a r v a t i o n i s important, as a lower degree of s t a r v a t i o n may give opposite r e s u l t s , i n . r e l a t i v e percentages of calcium, and magnesium, to a greater degree of s t a r v a t i o n , as compared to the c o n t r o l s . This d i f f -erence i n degree of s t a r v a t i o n might account, i n p a r t , f o r the d i f f e r e n c e i n the r e s u l t s of t h i s w r i t e r to those of Snow men-'tioned above, as i n t h i s case the potassium d e f i c i e n t plants showed no e x t e r n a l d e f i c i e n c y symptoms, whereas those of Snow di d . Let i t be noted that Snow reported that t r a n s p i r a t i o n decreased a f t e r an i n t e r v a l of time (p o s s i b l y as the d e f i c i e n c y became more severe). Hartt also found that the percentages of calcium, magnesium and phosphorus i n the potassium, d e f i c i e n t p l a n t s , i n r e l a t i o n to those i n the c o n t r o l s , v a r i e d with the age of the p l a n t . The work of JIartt (9) also showed that the percentage of sodium was very low i n the cases i n which i t was supplied as w e l l as those i n which i t was not. This corresponds with the r e s u l t s reported i n t h i s present paper, From both these r e s u l t s i t can be concluded that sodium did not replace potassium i n any f u n c t i o n measured i n these p l a n t s . However, M i l l e r (20) r e f e r s to several workers r e p o r t i n g that sodium may be s u b s t i t u t e d f o r potassium to a c e r t a i n degree, but not e n t i r e l y . This probably holds true f o r some but not a l l p l a n t s . Of the small f u l l n u t r i e n t tomato p l a n t s , s e r i e s 5, only two were analysed f o r mineral elements, the one w i t h the high-est and the one with the lowest t r a n s p i r a t i o n r a t e . The r e s u l t s of t h i s a n a l y s i s were very,• i l l u m i n a t i n g . The plant (b) w i t h the higher t r a n s p i r a t i o n r a t e , s i m i l a r to that of the potassium d e f i c i e n t p l a n t s , s e r i e s 2, had a low percentage of potassium, comparable to that of s e r i e s 2. On the other hand the one (a) w i t h the lower t r a n s p i r a t i o n r a t e , s i m i l a r to that of the c o n t r o l p l a n t s , s e r i e s 1, had a percentage of potassium comparable to that of the large f u l l n u t r i e n t c o n t r o l s , s e r i e s 1. Why a p l a n t r e c e i v i n g f u l l n u t r i e n t treatment should have such a low percentage of potassium i s not c l e a r , but, whatever the reason, i t s h i g h t r a n s p i r a t i o n r a t e r e f l e c t s i t s low potassium content. These small f u l l n u t r i e n t plants were the c o n t r o l s f o r the phosphorus d e f i c i e n t s e r i e s . The p l a n t s treated with a, n u t r i e n t s o l u t i o n i n which phosphate was replaced by c h l o r i n e , 47 showed the e f f e c t s of the d e f i c i e n c y w i t h i n three weeks. They showed no appreciable increase i n growth a f t e r feeding w i t h the phosphorus d e f i c i e n t s o l u t i o n s commenced. Since these p l a n t s were so small? they could not properly he compared to large f u l l n u t r i e n t and potassium d e f i c i e n t p l a n t s with regard to t r a n s p i r a t i o n . To get pl a n t s large enough so that trans-p i r a t i o n could conveniently he measured, other normal plan t s were treated w i t h f u l l n u t r i e n t and potassium d e f i c i e n t nut-r i e n t s o l u t i o n s f o r one month and then deprived of phosphate. In both cases •(- P and - PK) t r a n s p i r a t i o n , as w e l l as height i n and weight* •-^as much l e s s than Athe comparable small f u l l nut-r i e n t p l a n t s transplanted at the same time to s i m i l a r 'small s i z e d cans. These phosphorus d e f i c i e n t p l a n t s were i n both cases (- P and - PK) about equally low i n per cent phosphorus r e l a t i v e to the large c o n t r o l s . They were also r e l a t i v e l y low i n per. cent potassium, the - PK pl a n t s being the lowest. In both cases these two s e r i e s , 3 and 4, were r e l a t i v e l y high i n per cent calcium compared to both the large and the small f u l l n u t r i e n t c o n t r o l s . Yet, t h i s high calcium and low potassium content was associated w i t h low not high t r a n s p i r a t i o n r a t e . This i n d i c a t e s that a'deficiency of phosphorus i s dom-inant i n i t s e f f e c t s on t r a n s p i r a t i o n over a d e f i c i e n c y of potassium occuring at the same time. I t also appears that a d e f i c i e n c y of phosphorus r e s u l t s i n a d e f i c i e n c y of potassium. These r e s u l t s may, of course, hold true only f o r tomato tops, and not f o r other p l a n t s . Prom an examination of the mineral a n a l y s i s data, i t i s seen that the p l a n t s watered with the potassium d e f i c i e n t 48 n u t r i e n t s o l u t i o n , showed a s u r p r i s i n g l y large amount of potassium f o r plants supposodly r e c e i v i n g none i n the n u t r i e n t . s o l u t i o n . The answer must l i e i n the tap water used to d i l u t e the n u t r i e n t s o l u t i o n s and to water the p l a n t s . I t was thought at the time, that the Vancouver tap water was s u f f i c -i e n t l y pure to use i n place of d i s t i l l e d water f o r t h i s exper-iment. I t seems, though, that i t contains enough potassium, at l e a s t i n the summer, to allow a f a i r growth of tomatoes when' s u f f i c i e n t of the other n u t r i e n t s are present. At that i t need not contain very much potassium, as Johnston and Hoagland (13) have found that optimal growth of the tomato plant could be obtained i n a f l o w i n g s o l u t i o n w i t h a concentration of approximately 5'"p'.p.m. of potassium. Tap- water has been found to contain about 2 p.p.m. of potassium (23), though of course, i t w i l l vary from, d i s t r i c t to d i s t r i c t . This explains, then, why the s e r i e s B tomato p l a n t s . In which h a l f the potassium of the n u t r i e n t s o l u t i o n was replaced by sodium, t r a n s p i r e d as much as the f u l l n u t r i e n t c o n t r o l s . They were not a c t u a l l y d e f i c i e n t i n potassium. Some p l a n t s , i n c l u d i n g the tomato, can make s a t i s f a c t o r y growth i n - c u l t u r e s o l u t i o n s containing even l e s s than 1 p.p.m. of•phosphorus according to Tidmore (31). But, since phosphate d e f i c i e n c y showed up very q u i c k l y i n these experiments, the Vancouver tap water has not enough phosphorus to i n t e r f e r e s e r i o u s l y w i t h such experiments. These experiments on the tomato have shown that a pa . r t i a l d e f i c i e n c y of potassium r e s u l t s i n a s i g n i f i c a n t increase In t r a n s p i r a t i o n . The exact r o l e , though, that the potassium 49 plays i n the conservation of water i n the plant i s at present unknown. I t was hoped that the "plant sap" experiments and the "further t r a n s p i r a t i o n t e s t s " might throw some l i g h t on t h i s , hut they d i d not. However, since i n the "further trans-p i r a t i o n t e s t s " a t r a n s f e r of some normal plan t s to a potassium d e f i c i e n t n u t r i e n t s o l u t i o n and some others to a f u l l n u t r i e n t s o l u t i o n , d i d not r e s u l t i n any s i g n i f i c a n t d ifference i n t r a n s p i r a t i o n , i t would seem that conditions w i t h i n the plant .and not the composition of the n u t r i e n t s o l u t i o n was the cause of the increase i n t r a n s p i r a t i o n i n the f i r s t experiment. I t would seem, too, that sodium had no e f f e c t upon t r a n s p i r a t i o n i n these experiments., Since no c e r t a i n e x p l a i n a t i o n can Toe given, one can only give some suggestions as to probable p o s s i b i l i t i e s . For ex-ample,, since the upper surfaces of'potash d e f i c i e n t leaves have a d u l l appearance because of the f a c t , according to E c k s t e i n , Bruno and Turrentine ( 5 ) , that the epidermal c e l l s have only a very t h i n l a y e r of wax or none at a l l , p o s s i b l y the d e f i c i e n t p l a n t s lose more water through c u t i c u l a r trans-p i r a t i o n than do normal p l a n t s . These-writers also claim that the stomata close very s l u g g i s h l y when potash i s d e f i c i e n t , and that the d e f i c i e n t p l a n t s cannot so r e a d i l y adapt them-selves to dry weather and ..unfavorable s o i l moisture conditions as can normal p l a n t s . These same w r i t e r s are not r e p o r t i n g experiments of t h e i r own, but are summarizing the r e s u l t s of ether workers, mostly German. They have the f o l l o w i n g to say i n e x p l a i n a t i o n of the a c t i o n of potassium. "The m o d i f i c a t i o n s of the water r e l a t i o n s h i p s brought 50 about by' potash d e f i c i e n c y are r e l a t e d to a m o d i f i c a t i o n of the s w e l l i n g power of the p l a n t ' s c o l l o i d a l m a t e r i a l s . Monavalent ions, such as potassium, penetrate e a s i l y into the c e l l s , cause a s w e l l i n g of the surface l a y e r of the plasma, and pro-mote the absorption of water by the plant c e l l s . Divalent ions, such as calcium, on the other hand, penetrate w i t h great d i f f i c u l t y . They hinder the absorption and favor the escape of water. ..... The enlargement of the opening of the stomata when potash i s d e f i c i e n t , which i s regarded as one of the p r i n c i p a l reasons f o r the great l o s s of water from the p l a n t , i s due to the f a c t that because of the lower s w e l l i n g capacity of p l a n t m a t e r i a l and, the lower r e g u l a t i n g a b i l i t y i n the plasma demarcation l a y e r s , the c e l l pressure necessary f o r the c l o s i n g of these c e l l s cannot be maintained." Since the d e t a i l s of the process of excessive t r a n s p i r a t i o n , i n p l a n t s p a r t i a l l y d e f i c i e n t i n potassium, are unknown, f u r t h e r experiments are d e s i r a b l e with both tomatoes and other p l a n t s . To throw more l i g h t on the problem, the f o l l o w i n g points., and p o s s i b l y a number of others, need to be determined: ( l ) Whether the increase i n t r a n s p i r a t i o n rate r e l a t i v e to the c o n t r o l s i s constant o r . v a r i e s with some of the c l i m a t i c f a c t o r s a f f e c t i n g t r a n s p i r a t i o n (page 2)% (2) Whether the increase i n t r a n s p i r a t i o n rate r e l a t i v e to the c o n t r o l s i s greater during the day or night; (3) Whether or not there i s any r e l a t i o n between stomatal movements i n the d e f i c i e n t plants as compared wi t h the c o n t r o l s and various environmental con-d i t i o n s ; (4) VJhether the water absorbing power of the root has any r e l a t i o n to the increased t r a n s p i r a t i o n of the potassium 51 d e f i c i e n t p l a n t s ; (5) Whether dif f e r e n c e s i n root pressure have any r e l a t i o n to the problem; and (6) Yl/hether or not trans-p i r a t i o n i s increased f o r a l l degrees of potassium d e f i c i e n c y . SIJMMARY Using Hoagland's n u t r i e n t s o l u t i o n s under the conditions of t h i s experiment, the f o l l o w i n g r e s u l t s were obtained. (1) Tomato plant s p a r t i a l l y d e f i c i e n t i n potassium, tested at the time of blossoming, were found to tr a n s p i r e s i g n i f i c -a n t l y more per u n i t of green weight of top than d i d comparable c o n t r o l p l a n t s . (2) Tomato plant s p a r t i a l l y d e f i c i e n t i n phosphorus, and i n phosphorus together wi t h potassium, on the other hand, t r a n s p i r e d much l e s s than comparable c o n t r o l s . (3) Tr a n s p i r a t i o n of r a d i s h p l a n t s p a r t i a l l y d e f i c i e n t i n potassium was not s i g n i f i c a n t l y d i f f e r e n t from that of com-parable c o n t r o l s . (4) Tomato plants p a r t i a l l y d e f i c i e n t i n potassium and also those . p a r t i a l l y d e f i c i e n t i n "'phosphorus were found to have a s i g n i f i c a n t l y greater proportion of l e a f to t o t a l top than the comparable c o n t r o l s . (5) Ko constant or regular r e l a t i o n was found between the t r a n s p i r a t i o n and the osmotic pressure of the pl a n t sap of tomatoes. (6) Sodium does not appear to be able to replace potassium i n r e l a t i o n to i t s r o l e i n t r a n s p i r a t i o n i n tomato p l a n t s . (7) Tomato pl a n t s p a r t i a l l y d e f i c i e n t i n potassium were s i g n i f i c a n t l y higher i n percentage of calcium and of magnesium than were comparable c o n t r o l s . (8) Vancouver tap water i n summer contains s u f f i c i e n t potassium, but not s u f f i c i e n t phosphorus, to pa.rtia.lly sunply the needs of tomato and r a d i s h p l a n t s f o r a d e f i c i e n c y of these elements. 53 LITERATURE CITED (1) Bouyoucos, G. J. : T r a n s p i r a t i o n of wheat seedlings as a f f e c t e d by s o i l s , by s o l u t i o n s of various d e n s i t i e s , and by various chemical compounds. Jour. Amer. Soc. Agron. 3: 130-191. 1911. (S 22, A'7) (2) * B u r g e r s t e i n , A.:. Untersuchungen uber die Bezidhungen der Ilahrstoffe zur T r a n s p i r a t i o n der Pflanzen Sitzungs-ber. Akad. Y/iss. Wien. Math. Hat. CI. 83; 191. 1876. . (3) C h i l d e r s , IT. F. and Co wart, F. E. : The photosynthesis, t r a n s p i r a t i o n , and stomata of apple leaves as a f f e c - •' ted by c e r t a i n n u t r i e n t d e f i c i e n c i e s . Proc. Am. Soc. Hort. S c i . 33:'160-163. 1935. ( S B 1 , A 13) (4) Colby, H. L.: E f f e c t of s t a r v a t i o n on d i s t r i b u t i o n of mineral n u t r i e n t s i n 'French prune trees.grown i n s o l u t i o n c u l t u r e s . Plant P h y s i o l . 8: 357-394. 1933. (QK 1, P 4) (5) E c k s t e i n , 0., Bruno, A. and Turrentine, J. W. : Potash De f i c i e n c y Symptoms. V e r l a g s g e s e l l s c h a f t Fur Ackerbau H. B. H. B e r l i n SW 11. 1937. X I I +• 235 pp. i n c l . LIV p l a t e s . (S 645, E 2) (6) Fonder, J. F.: V a r i a t i o n s i n potassium content of a l f a l f a due to stage of growth and s o i l type and the r e l a t i o n s h i p of potassium, -and calcium i n p l a n t s grown upon d i f f e r e n t s o i l types. Jour. Amer. Soc. Agron. 21: 732-750. 1929. (S 22, A 7) (7) * H a l l , A.. D, : The Book of the Rothamstead Experiments. Ed. 2 rev. by E. J. R u s s e l l , p 59, 87. London, J. Murray. 1917. 54 (8) * Hansteen-Cranner, B.: Uber das Verhalten der Kultur-" pflanzen zu den Bodensalzen. I I I . Jahrb. Wiss. Bot, 53 s 536-602. 1914. (9) f l a r t t , C. E. s Some e f f e c t s of potassium upon the growth of sugar cane and upon the absorption and migration of ash con s t i t u a n t s . Plant P h y s i o l . 9: 399-451. 1934. (QK 1,- P 4) (10) Hoagland, I). R. ; R e l a t i o n of the concentration a.nd r e -a c t i o n of the nu t r i e n t medium to the growth and ab-so r p t i o n of the pla n t . Jour. Agr. Res. 18; 73-117. 1919. (S l s J 72) (11) *Hoblyn, T.: The ,Journal of Pomology and Fort. Science. Bd.' IX, S. 303. 1931. . ^ (SB 354, J 5) (12) James, W. 0.; Studies on the p h y s i o l o g i c a l ' importance of the mineral elements i n pl a n t s . I, The r e l a t i o n of potassium to the proper t i e s and functions of the l e a f . Ann. Bot. 44: 173-198. 1930. (OK 1, A 47) (13) Johnston, j j . S. and Hoagland, D. R. : Minimum potassium. l e v e l required by tomato plan t s grown i n water c u l -tures. ..Soil S c i . 27; 89-109. 1929. (S 590, S 6) (14) * K i s s e r , J. : Untersuchungen uber den E i n f l u s der Nahrsa.lz a„uf die Wasserabgabe Wasserautname, r e l a t i v e Spross-und Wurzelmass und die B l a t t a t r u k l t u r . , P l a n t a 3; 562-577. 1927. (15 )*Kostytschew, S. and E l i a s b e r g , P.; Uber die Porm der Kaliumverbindungen i n lebenden Pflanzengeweben. Z. p h y s i o l . Chem. I l l : 228-235. 1920. 55 (16) *Lawes, B.; An experimental i n v e s t i g a t i o n into the amount of water given o f f by plants during t h e i r growth. Jour. Hort. Soc. London. 5: 38. 1850. (17) *Maercker, "M.: Versuche uber die Beeinf lussung des Wasser verbrauchs der Pflanzen durch die K a l i r o h s a l z e . Jahrb. agr. .chem. Vers. Stat. H a l l e , pp. 15-16. 1895 (18) McCance, R. A. and Shipp, H. L.: The chemistry of f l e s h foods and t h e i r losses on cooking. • Sp. Rep, Ser. Ked. Res. Coun. Ho. 187. 1933. (TX 555, M 3) (19) Meyer, B. S.; E f f e c t of mineral s a l t s upon the trans-p i r a t i o n and water requirements of the cotton p l a n t . Amer. Jour. Bot. 18: 79-93. 1931. ' (QK 1, B 345) (20) M i l l e r , E. C. : P l a n t Physiologjr. x x x i 1201 pp, 2nd. Ed, .McGraw-Hill Book Company, Inc. Hew York and London. 1938. (QK711,'M5, 1938) (21) Morrow, C. A. : Biochemical Laboratory Methods f o r Students of the B i o l o g i c a l Sciences. John Wiley & Sons Inc. Hew York. 1927. .(QK 861,-M 66) Chapter I I . P h y s i c a l Chemical Constants of Plant Saps. pp. 75—89. (22) Morse, E. W. : R e l a t i o n between water and potash i n plant production. Jour. Agr. Res. 35; 939-946. 1927, (S 1, J 72) (23) N i g h t i n g a l e , G. T. , Schermerhorn, L. G. and Bobbin's, W. R.: Some e f f e c t s of potassium d e f i c i e n c y on the h i s t o l o g i c a l structure and nitrogenous and carbo-hydrate c o n s t i t u a n t s of p l a n t s . Hew Jersey Agr. Exp. Sta. B u l l . 499., 1930. 56 (24) Parker, i \ W. and P i e r r e , W. H. : The r e l a t i o n between the concentration of mineral elements i n a c u l t u r e medium and the absorption and u t i l i z a t i o n of those elements by p l a n t s . S o i l S c i . 25; 337-343. 1928. (S 590, S 6) (25) Paterson, D. D.: S t a t i s t i c a l Technique i n A g r i c u l t u r a l Research,' i x + 263 pp. McGraw-Hill Booh Company, Inc. Hew York and London. 1939. (HD 1425, P 3) (26) Reed, H. S.; The e f f e c t of c e r t a i n chemicals upon the growth and t r a n s p i r a t i o n of wheat seedlings. Bot, Gaz. 49; 81-109. 1910. (QK 1, B 3) (27 )* Richards, Theo. W. and Wells, R. C.J Hephelometer, an instrument f o r detecting and estimating opalescent p r e c i p i t a t e s . Amer. Chem. J. 31: 235-243. 1904. Sachs, J. : Uber den E i n f l u s der chenischen und p h y s i -h a l i s c h e n Beschaffenheit des Bodens 'auf die Trans-p i r a t i o n der Pflcinzen. Landw. Versuchsst. 1; 203. 1859. (29) S h e r r i l l , E.; C e n t r i f u g a l method f o r determining potash. Jour. Ind. & Eng. Chem. 13: 227. 1921. (TP 1, J 6) (30) Snow, A. G. j r . : T r a n s p i r a t i o n as modified by potassium. Plant P h y s i o l . 11: 583-394. 1936. (QK 1, P 4) (31) Tidmore, J. W.: The phosphorus content of the s o i l s o l -u t i o n and i t s r e l a t i o n to plant growth. Jour.' Amer. Soc, Agron. 22: 481-499. 1930. (S 22, A 7) Phosphate studies In s o l u t i o n c u l t u r e s . S o i l S c i . 30: 13-33, 1930. (S 590, S 6) (2 5 7 ( 3 2 ) T i n c k l e r , M. A. K. and D a r b i s h i r e , E. V . : Studies on the formation of tubers and storage organs. The i n f l u -ence upon t r a n s l o c a t i o n of the period of l i g h t and the supply of potassium. Ann, Bot. 4 7 : 2 7 - 5 1 . 1 9 3 3 . ' - . (OK 1, A 4 7 ) ( 3 3 ) Wall, M. E . : Microdetermination of some constituants of p l a n t ash. Plant P h y s i o l . 1 5 J 5 3 7 - 5 4 5 . 1 9 4 0 . (QK 1 , P : .4 ) ( 3 4 ) Wallace, T.: Long Ashton Research S t a t i o n Reports. 1 9 2 9 , S. 4 7 - 5 8 and 1 9 3 1 , S. 1 7 - 2 7 . ^ Papers thus marked were not read i n the o r i g i n a l . The w r i t e r ' s knowledge of them i s based on extracts and references which have appeared i n the various other papers here l i s t e d . The l e t t e r s and f i g u r e s given i n brackets at the end of most of the references are the L i b r a r y of Congress (also U. B. C. L i b r a r y ) c a l l numbers, by which the references may be q u i c k l y located. 58 This w r i t e r extends thanks to Dr. G. H. H a r r i s , Associate Professor of H o r t i c u l t u r e , under whose supervision t h i s work was done, f o r suggesting the topic and f o r h i s advice through-out the course of the work. Acknowledgement i s also given to. Dr. A. P.- Barss, Professor and Head of the Department of H o r t i c u l t u r e , f o r h i s k i n d l y i n t e r e s t i n the work. 59 APPENDIX Photographs taken at the time of the t r a n s p i r a t i o n t e s t s i n August 1937. .1) The balances used i n the t r a n s p i r a t i o n test: (2) The r a d i s h p l a n t s , Potassium D e f i c i e n t (- K), and P u l l Nutrient (P S). Notice that the - K t are f u l l y as w e l l developed as the P N ones, are representative plants from each s e r i e s . ops These 6 0 (3) Tomato p l a n t s , Potassium D e f i c i e n t - - s e r i e s 2 (- K ) , and P u l l Nutrient - s e r i e s 1 (P N). Notice that the - K pla n t s are as w e l l developed as the P'N ones. (4) Tomato p l a n t s . Notice that those i n the center, the small f u l l n u t r i e n t c o n t r o l s - ser i e s 5 - are the t a l l e s t and have the l a r g e s t leaves, while the Phosphorus D e f i c i e n t (- P) pl a n t s - s e r i e s 3 - on the r i g h t are the smallest, and l i k e those on the l e f t , D e f i c i e n t i n both Phosphorus and Potassium (- PK) - s e r i e s 4 - have smaller leaves. 61 7 (5) Tomato plant s - the Recovery Seri e s . Notice that those on the l e f t (- P) - seri e s 6 - fed with f u l l n u t r i e n t have made a greater recovery from phosphorus d e f i c i e n t treatment than those on the r i g h t (- PK) - se r i e s 7 - fed with potassium d e f i c i e n t n u t r i e n t s o l u t i o n have made from combined phosphorus and potassium d e f i c i e n t treatment. 6 each s e r i e s i s shown.