Role of enzymatic wall-softening in plant morphogenesis: hormonal induction in Achlya.

Sexual hormone A, which induces antheridial branching in male strains of Achlya, also elicits a rise in cellulase. The peak of induced cellulase corresponds in time with the appearance of branches that are the male sexual organ primordia; only those strains that branch in response to the hormone show a concomitant rise in cellulase. The response to the hormone is inhibited by compounds that block protein synthesis, for example, p-fluorophenylalanine and puronmycin. Vegetative branching, induced by substrates such as casein hydrolysate, is also accompanied by a rise in cellulase.