Auxin-regulated Wall Loosening and Sustained Growth in Elongation

Publisher Website
Google Scholar
Abstract
It is proposed that auxin regulates and coordinates both wall loosening and the supply of wall materials in elongation. The tenets of the proposal allowed testable predictions. It was determined that, if the cell walls of Glycine max L. var. Wayne hypocotyl segments are maintained in a loosened state (by excising the segments directly into pH 4 medium), exogenous auxin induced only the 2nd response. It was also predicted and confirmed that elongating systems, e.g., pea epicotyl, with certain early auxin-induced growth kinetics (an initial high non-steady-state rate followed immediately by a drop to a lower steady-state rate) would show a transient 2nd response (in addition to the usual transient 1st response) when stimulated by pH 4 medium. Recent results which establish the existence of auxin-induced elongation-associated proteins support the proposition that auxin coordinates wall loosening and the supply of wall materials in elongation.
Keywords