ENDOGENOUS IAA AFTER TRYPTOPHAN APPLICATION IN THE WILD-TYPE AND AN AUXIN-INSENSITIVE MUTANT (86.1 = CAL 1) OF THE MOSS FUNARIA-HYGROMETRICA HEDW

Mutant 86.1 (CAL 1), isolated by uv irradiation of protoplasts, remains in the chloronema state (caulonema free) throughout its growth on minimal medium as well as on tryptophan-supplemented medium. In contrast, wild type shows spontaneous differentiation from chloronema to caulonema when raised on minimal medium and caulonema differentiation is further enhanced by tryptophan treatment. HPLC-ELISA determinations of endogenous IAA levels reveal that the tryptophan uptake and IAA biosynthesizing systems are fully operational in the mutant 86.1 (CAL 1). The mutant exhibits a steady increase in the endogenous IAA level with age, further enhanced by tryptophan application. The mutant appears to be more active in IAA biosynthesis than the wild type. Present findings indicate the possibility of disruption in the auxin reaction system in the mutant.