Effects of Isosmotic Concentrations of Inorganic and Organic Substrates on Entry of Water into Corn Roots

The data are interpreted as indicating that the osmotic pressure of the substrate is one of the primary factors in controlling the rate of entry of water into roots. It is also recognized that the character of the solute and toxicity of salts or ions may have a significant bearing on the function of water intake, and further experiments are planned-especially with mixed salts. The conflicting data regarding the effect of organic substrates are discussed in the light of other work. The results with inorganic substrates indicate that, under the conditions of these experiments, no significant differences in rate of intake occur when isosmotic pressures of Na2SO4, NaCl, or CaCl2 are used as single salts.