Physiological and Morphological Differences in the Roots according to Nodes Succession in Rice and Wheat Plants

[摘要] As the development of roots begins at lower nodes and proceeds periodically to upper nodes, the roots from the upper nodes are younger than those from the lower nodes. In this experiment the author investigated physiological and morphological differences of foots elongating from the successive nodes of the main stem. 1. Coloring of the roots : In both rice and wheat, it was observed that the young fresh white color diminished and the yellowish brown color deepened successively from the upper nodes toward the lower ones. 2. Size of the roots : As these roots do not have secondary thickening growth, in principle, the size of a root base is constant throughout all the phases of growth. Diameters of root bases in upper nodes were larger than those of lower nodes. The root of the largest diameter was observed in the 10 th node in rice plant and in the 6 th node in wheat-it was 1.36 cm in rice and 1.26 cm in wheat. And conversely diameters of those root bases upper than the largest successively decreased. 3. Number of the roots : In a rice plant the number of roots increased successively from the lower node towards the upper node-the largest unmber was observed in the 10 th node-it was 23.3. A wheat plant has commonly 3 in every node. 4. Amount of the oxygen absorption in water : As the upper the roots were the younger, they absorbed larger amount than those of the lower nodes. The difference of the amount in the successive node of a rice plant was larger than that of a wheat plant. 5. Angle of the roots emergence : The angle of the roots emergence to the main stem became larger successively from the lower nodes toward the upper nodes-the roots of the 11th node presented 92.1 on the average.

[学科分类] 农业科学（综合）