Abstract
Protonema cells of the moss Physcomitrella patens develop freezing and dehydration tolerance upon treatment with abscisic acid (ABA). To understand mechanisms underlying physiological processes leading to development of stress tolerance, we isolated P. patens mutant lines with reduced sensitivity to ABA. Among these lines, AR7 showed growth similar to wild type but did not develop freezing or dehydration tolerance by ABA treatment. Analysis of low molecular-weight soluble sugars indicated that AR7 protonema cells accumulated less but significant amounts of sucrose upon ABA treatment. In contrast, AR7 accumulated very little amounts of trisaccharide theanderose. Results of analysis of LEA-like heat soluble proteins in the AR7 mutant will also be presented.
