INFLUENCE OF AUXIN ON CELL-WALL METABOLISM

Abstract

The C atoms of Cl4-methyl-labeled methionine and of glucose uniformly labeled with C14 are rapidly incorporated into cell-wall constituents of oat coleoptile sections. Incorporation of the C of methyl-labeled methionine or of glucose into a particular wall fraction, the hot-water-soluble portion, is enhanced in presence of the plant hormone indole-3-acetic acid (IAA) even if IAA-induced growth of the tissue is suppressed by a suitable external osmotic concentration. Methyl-derived C14 incorporated into the hot-water-soluble or dilute-alkali-soluble portions of the coleoptile wall is slowly lost again when the tissue is incubated in un-labeled methionine. This decorporation of methyl-derived C is slowed in the presence of IAA. Similar decorporation of glucose C is depressed by IAA.