THE FUNCTION OF ABSCISIC ACID IN BRYOPHYTES

Abstract

Abscisic (ABA) acid has been detected in all members of Bryophyta which have been analysed until now. Highest ABA contents were detected in species that were adapted to dry environmental conditions, lowest amounts were found in aquatic and hydrophilic species. Abscisic acid seems to be involved in several ecophysiological and developmental processes. I) ABA induces stomata! closure in stomata-bearing sporophytes of Anthocerotae and Musci; 2) ABA induces desiccation tolerance in several drought resistant members of the Marchantiales and in Funaria-protonemata. 3) ABA converts the waterform of Riccia fiuitans L. (submerged living) and Ricciocarpus natans L.Corda (floating on the water surface) into the landform. Ecophysiological as well as molecular biological experiments will be discussed.