A Study of the Role of the Hydrogen Ion in the Mechanism of Potassium Absorption by Excised Barley Roots.

precedingw or following irrigations. No reduction in the rate of photosynthesis was cletected as soil moisture was extracted, until the approximate time the first visible signs of wilting appeared. As the severity of wilting increased, the photosynthetic rate declined rapidly. When the plants were (listinctly wilted, photosynthetic activity had been reduced to approximately 75 % of its maximum value. Severely wilted plants irrigated one day after the permanent wilting percentage had been reached showed 40 to 50 % increases in rate of photosynthesis within 6 hours. Experiments carried out under continuous light supported the above conclusion. The respiration rate of the aerial portions of the ladino clover plant tended to increase slightly as wilting appeared. These increases were relatively much smaller than accompanying changes in photosynthesis. Results of these studies are in accord with those of Allmendinger et al on apple trees and of Loustalot on pecan trees, but differ in degree from those of Schneider and Childers on apple trees.