The Physiological Role of Indole Acetic Acid in the Moss Funaria hygrometrica Hedw. : II. Mutants of Funaria hygrometrica which Exhibit Enhanced Catabolism of Indole-3-Acetic Acid

Abstract

Indole-3-acetic acid (IAA) was analyzed in wild type and two mutants of Funaria hygrometrica Hedw. by high performance liquid chromatography (HPLC) — enzyme immunoassay (EIA). The mutants are unable to develop caulonema without addition of exogenous auxin or auxin precursors. This correlated with the fact that the wild type protonema yielded 50–70% more endogenous IAA than the mutants. After feeding tryptophan to the wild type and one of the mutants, they both accumulated more than five times higher amounts of IAA compared to the normal endogenous content. Whereas the wild type metabolized this excess of IAA very slowly, the mutant reduced the accumulated auxin to the original endogenous level within five days.