COMPARISON OF ABSORPTION OCCURRING IN CORN 
STAUK TISSUE AND IN PREPARED BIOCOLEOIDS 
L. E. YOCUM AND A. L. BAKKE 
Growth, an important function of the plant, is characterized 
by being possible under a wide range of temperature, moisture, 
available plant food, and other limiting factors. It is a hydra- 
tion of the colloidal material (protoplasm) of the plant to which, 
later in the life of the plant, matter is added. This added matter, 
of course, increases the dry weight. Protoplasm has been found 
to adhere so closely in its actions to the laws of artificially con- 
structed biocolloids that many attempts are being made to con- 
struct a biocolloid whose behavior agrees with the observed 
behavior of protoplasm and in that way to determine more defi- 
nitely its detailed structure and composition. The present study 
is an attempt to set forth the rate of hydration in corn stalk 
tissues and in artificially prepared biocolloids. 
MacDougal and Spoehr ^ have carried on extensive work along 
the line of growth as related to increase in size of plant parts. 
Spoehr ^ has determined the constituents and their arrangement 
in the cell and MacDougal and Spoehr ^ have investigated the 
rate of hydration in many biocolloids. MacDougal ^ has com- 
pared their absorption with that in joints of Opuntia. 
MacDougal ® and Shull ® show that increases in temperature 
cause increases in absorption according to definite ratios. Mac- 
Dougal has found that the maximum swelling of agar and protein 
takes place at about 40° C., but that the higher the temperature, 
the greater the early hydration, with a consequent earlier state 
of complete saturation. He also noted that above 18° C. water 
is absorbed by Opuntia more rapidly than are acid or alkaline 
solutions. 
Material and Methods . — Corn stalk tissue was taken from 
1 MacDougal, D. T., and H. A. Spoehr. Growth and Imbibition. Proc. Am. Phil. 
Soc., vol. 56, p. 289. 1917. 
2 Spoehr, H. A. Carbohydrate economy of cacti. 
3 MacDougal, D. T., and H. A. Spoehr. The effect of acids and salts on biocol- 
loids. Science N. S., vol. 45, p. 484. 1917. 
4 MacDougal, D. T. Imbibitional swelling of plants and colloidal mixtures. Sci- 
ence N. S., vol. 44, pp. 502-505. 1916. 
5 MacDougal, D. T. Hydration and growth. Carnegie Inst. Wash. Pub. No. 297. 
1920. 
6 Shull, Charles A. Temperature and rate of moisture intake in seeds. Bot. Gaz., 
vol. 69. pp. 361-390. 1920. 
