Studies on the Stiffness of Culms in Barley Plants (Hordeum sativum, JESSEN) : 7. Relation between the development of nodes and bending moment in nodes.

Abstract

Relation between the development of nodes and that of bending moment in nodes was researched. The bending moment in nodes was exceedingly larger than that in internodes. In the basal nodes, the bending moment showed the most large value, and in upper nodes it showed lower value. Cross section of nodes was considered as an ellipse, so we measured the long diameter and minor diameter. On the other hand, nodes were constituted by the culm and leaf sheath, so we measured the length of longitudinal direction of nodes including the leaf sheath. Consequently, those values became larger with the development of culms. The growth of culms reached to the maximum at the heading stage and afterward it declined. It was considered that the breaking of nodes in Haganemugi (stiff culm variety) related to shriveling of tissue in nodes and decline of bending moment in nodes. The ratio of bending moment in nodes to in internodes indicated the degree of stiffness of culms.