Temperature Coefficient of Absorption in Seeds of Corn

Abstract

1. A study of the influence of wide temperature differences on the rate of water absorption by seeds of corn has been made, with results in complete agreement with a similar study of Xanthium seeds and pea cotyledons made previously. 2. The same type of formula, and the methods of mathematical analysis used with other seeds, were found to apply with great exactness to the data obtained with corn. 3. The temperature coefficient over the range from 5°-50° C. averages 1.537, somewhat above the coefficient for purely physical processes. This coefficient is to be compared with that of 1.55 for Xanthium seeds, and 1.6 for pea cotyledons. 4. The rate of absorption at 50° C. is somewhat more than eight times as fast as at 5° C., whereas the chemical theory of absorption would call for a rate thirty-two times as great. 5. The increase is therefore only one-fourth of what one would expect if absorption rates were determined by hydrone simplification of water as the temperature rises. 6. From mathematical considerations, the velocity of intake at any given moment must be considered as approximately an inverse exponential function of the amount of water previously absorbed. 7. Attention is called to a number of cases of irregular absorption rates, which indicate that many substances have specific absorption behavior. A rate law with wide applicability is not to be expected. 8. The importance of semipermeability with reference to the intake of water from solutions of various kinds is pointed out.