June lo. 1918 Transpiration of Corn and the Sorghums 



601 



ments in figures 7, 8, 11, and 12. Only one of these exceptions will be 

 mentioned here. The leaf surface of the plants used in the experiment 

 of July 26 and 27, 191 7, was 16,943, 6,710, 4,844 and 2,793 square centi- 

 meters, respectively, for Pride of Saline com, Dwarf Blackhull kafir. 

 Red Amber sorgo, and Freed's sorgo. The total amount of water trans- 

 pired per plant during the two days from 7 a. m. to 7 p. m. was 3,353 

 gm. for Pride of Saline corn, 1,702 gm. for Red Amber sorgo, 1,154 S™-- 

 for Dwarf Blackhull kafir, and 989 gm. for Freed's sorgo. 



Although in most cases the amount of water transpired by each plant 

 stood in the same relative order as the extent of leaf surface, the loss of 

 water from each plant was not proportional to the amount of leaf surface 

 exposed. For examples of this fact the results of the experiments of 

 July 20, 27, 30, and August 31, 191 7, are shown in Table IV. In this 

 table the ratio of the extent of the leaf surface of each of the sorghums 

 to that of the corn plant is shown, together with the ratio of the water 

 loss of each of the sorghum plants to that of com for every 2 -hour 

 period of the day from 7 a. m. to 7 p. m. From these examples it is 

 observed that the ratio of the water loss from the sorghum plants at 

 any given period to that of the com was higher than the ratio of the ex- 

 extent of leaf surface of these two types of plants. The only exception 

 to this was the Dwarf Blackhull kafir. The ratio of the amount of 

 water transpired by this plant to the amount transpired by the com 

 plant is lower than the ratio of the extent of the leaf surface of the 

 kafir to that of the com. 



Table I\'. — Relation of the amount of water transpired by corn and the sorghums to the 

 extent of the leaf surface of these plants 



Period ending- 



Ratio of- 



Dwarf milo to Pride of 

 Saline com. 



Leaf 

 surface. 



Loss of 



water per 



plant. 



Red Amber sorgo to 

 Pride of Saline com. 



Leaf 

 surface. 



Loss of 



water per 



plant. 



Freed's sotro to Pride 

 of Saline com. 



Leaf 

 siu^ace. 



Loss of 



water per 



plant. 



1917 

 July 20: 



9 a, m 



II a. m 



I p. m 



3 P- m 



5 P-m 



7P-m 



July 27: 



9 a. m 



II a. m 



I p. m 



3P.ni 



SP-m 



7P- m 



0.578 

 •578 

 •578 

 .578 

 .578 

 .578 



0.814 

 •773 

 .705 

 •748 

 •6ss 

 .422 



0.310 

 .310 

 • 310 

 .310 

 .310 

 .310 



0.540 

 .646 

 •572 

 .618 

 • 500 

 •394 



0^234 

 •234 

 •234 

 •234 

 •234 

 .234 



0.370 

 •392 

 .427 

 •47S 

 .461 

 .267 



Dwarf Blackhull kafir 

 to Pride of Saline 

 com. 



Red Amber sorgo to 

 Pride of Saline com. 



Freed's sorgo to Pride 

 of Saline com. 



0.396 

 •396 

 •396 

 •396 

 •396 

 •396 



0.414 

 •358 

 •372 

 •353 

 •333 

 • 230 



• 285 

 .285 

 .285 

 .285 

 .285 



0. 484 

 •479 

 •537 

 .587 

 .487 

 .298 



0. 164 

 . 164 

 . 164 

 . 164 

 . 164 

 . 164 



o^3l3 

 .282 

 ■3i5 

 •341 

 .268 

 • 240 



