Involvement of cellulose synthesis in actions of gibberellin and kinetin on cell expansion. Gibberellin-coumarin and kinetin-coumarin interactions on stem elongation

摘要

In azuki bean (Azukia angularis=Vignia angularis) epicotyl sections, 5×10−4Mcoumarin inhibited the incorporation of radioactivity from U−14Cglucose into the cellulose fraction by 35in the absence of indole-3-acetic acid (IAA) and by 40in the presence of 1×10−4MIAA. There was no inhibitory effect on the incorporation of radioactivity into the other fractions. Coumarin at 5×10−4Mreversed the promoting effect of 1×10−5Mgibberellin A3(GA) and the inhibitory effect of 1×10−5Mkinetin on IAA-induced elongation of sections with no significant effects on IAA-induced elongation. Neither GA nor kinetin had any appreciable effects on cellulose synthesis. No inhibition of cellulose syntheis was observed with 1×10−3Mcolchichine, which has been reported to have effects similar to those of coumarin on GA- or kinetin-affected stem elongation. Coumarin at 5×10−4Mwas ineffectual in breaking up wall microtubules, while a disrupting effect on wall microtubules was clearly demonstrated with 3×10−4Mcolchicine.From these results, the possible involvement of cellulose synthesis in cell expansion controlled by GA