Studies on the Stiffness of Culms in Barley Plants (Hordeum sativum, JESSEN) : 9. The negative geotropism of nodes.

Abstract

The negative geotropism of nodes in 6-rowed barley (2 varieties were used : Haganemugi, stiff culm variety, and Sekitorisai-No. 1, brittle bulm variety) were studied in relation to the stimulus and temperatures. Generally, the reaction of negative geotropism was larger in Sekitorisai-No. 1, and more apparently in the basal node than in upper nodes. Stimulus was larger and temperature was higher, the reaction became larger. But in Haganemugi, the reaction was different in each node, so it was considered that the physiological states in each node were different in the variety. The negative geotropism of nodes continued untill the late growth stage, and especially so in the upper nodes. The reaction was disappeared by the treatment of α-naphthalene acetic acid in nodes. From the auto-recording diagram of the reaction, it was pointed out that the reaction began soon after the beginning of stimulus and a half of reaction finished in 36 hours after the beginning of reaction.