Diurnal fluctuations in the acidity of tissue fluids in six to ten week old wheat plants were followed by potentiometric pH measurements of sap freshly expressed from plants at various hours of the day. A daily average fluctuation of 1.5 pH was observed in young plants. The range of pH variation was appreciably extended by increased illumination, maximum acidity occurring dur- ing the early hours of daylight and thereafter falling steadily until the minimum was attained several hours after dark. This degree of pH fluctuation is correlated with variations in the osmotic pressure of expressed sap and thus important in modifying the solubility of nutrients.
Proceedings of the Iowa Academy of Science
©1929 Iowa Academy of Science, Inc.
Loehwing, Walter F.
"Studies of the Diurnal Fluctuations of Sap Hydrion Concentration in Young Wheat Plants,"
Proceedings of the Iowa Academy of Science, 36(1), 242-242.
Available at: https://scholarworks.uni.edu/pias/vol36/iss1/38