Wall Extensibility in Relation to Auxin Effects

Abstract

Decrease in the minimum stress-relaxation time, To, is well correlated with the capacity of the cell wall to extend, but the increase in extensibility appears to be the expression of an extension that has already occurred. Decrease in To of a cell wall specimen results following treatment with a fungal exo-type β-1,3-glucanase or 0.1N KOH, but only to a limited degree with cellulase or 0.1% ammonium oxalate. Auxin causes a decrease in the hemicellulosic glucose level in the cell wall after a lag period of 2 h when it induces cell extension. Hydrogen ions cause cell extension without decreasing the glucose level in the wall. Auxin effects on extension and glucose level are inhibited by nojirimycin, a potent inhibitor of glucanases, which does not, however, inhibit hydrogen ion-induced cell extension and To decrease.