Temperature-growth Relations of the Roots and Hypocotyls of Cotton Seedlings.

Whether root systems an(d tops of plants are essentially alike or notably different with regard to their temperature relations is an importanit question in fundamental plaiit physiology, as well as in ecology, in pathology, and in the study of the climatic distribution of plants in nature and in cultivation. This general question is dealt with in the present paper with respect to seedlings of the cotton plant, Gossypiutm hirsuht nt L. The results presented show elong,ation rates of primary roots and hypocotyls for each of 8 different maintained teimiperatures, all parts of each seedling being exposed to the same temperature. Data are also ineluded on the development of cotyledons and secondaryroots anid on seedling weights.