CHANGES IN SOLUBLE AND IONICALLY BOUND PEROXIDASE ACTIVITIES DURING BRASSICA JUNCEA SEED DEVELOPMENT

Abstract

Summary. Changes in peroxidase activity was analyzed in developing mustard (Brassica juncea) seed. The activity in soluble and bound fraction was assayed with three hydrogen donors viz. ferulic acid, caffeic acid and chlorogenic acid. Growth was measured in terms of dry weight and water content. Seed dry weight data was fitted to a cubic polynomial equation. The rate of dry matter accumulation was calculated by differentiating the best-fit cubic polynomial. A close parallelism between water content and dry matter accumulation was observed in developing mustard seed. The peroxidase activity was less during initial phase of seed development and showed a rising trend after d 20. Thus the activity showed an inverse correlation with water content. This inverse correlation suggests an important role of peroxidase in termination of the process of cell elongation of mustard seed. Key words: Brassica juncea, seed development, peroxidases, cell walls