Gibberellic acid, β-1,3-glucanase and the cell walls of barley aleurone layers.
A glucanase from barley aleurone layers can be assayed using the algal polysaccharide laminarin as substrate. Gibberellic acid (GA3) enhances the release of this enzyme from isolated aleurone layers but has no significant effect on its synthesis. Concentrations of GA3 effective in stimulating this release are in the range of 3×10(-11)-3×10(-7)M. The time course of glucanase release was found to be significantly different from that of α-amylase, glucanase release being completed before that of α-amylase. Evidence based on using various histochemical stains suggests that barley aleurone cell walls contain a β-1,3-linked polymer. Following treatment of aleurone layers with GA3, digestion of these walls is seen to occur. These observations strongly suggest that the β-1,3-glucanase produced by aleurone cells is resposible for the observed cell-wall digestion.
Department of Botany, University of California, Berkeley.
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Taiz
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Jones