Effects of auxin on wall polysaccharide composition and enzyme activity during extension‐growth of Pellia (Bryophyta)

Abstract

Auxin‐induced changes in cell wall polysaccharide composition and enzyme activity of seta segments from the liverwort Pellia epiphylla (L.) Corda were studied using colorimetric, gas chromatographic, radioactive tracer, and viscometric techniques. Extension‐growth of segments doubled in the presence of aqueous 10 μM indole‐3‐acctic acid (IAA) ± 50 mM glucose. IAA‐enhanced growth was accompanied by (1) enhanced synthesis of all wall polysaccharides but cellulose, (2) increase in the relative glucose content of neutral wall sugars, and (3) change in the activity of wall‐bound glycosidase relative to controls, but no change in the activity of cellulase. Galactose and mannose (50 mM) suppressed auxin enhancement of both growth and wall synthesis. These findings suggest that auxin‐mediated extension‐growth of Pellia setae is dependent upon the maintenance of non‐cellulosic cell‐wall synthesis.