Protein Synthesis during Adventitious Bud Initiation in Superficial Layers of Torenia Stem Segments Cultured in vitro

Abstract

Summary In Torenia stem segments cultured in vitro, adventitious bud initiation takes place in epidermal cells. The initiation was promoted by a cytokinin and inhibited by some inhibitors of RNA and protein synthesis such as actinomycin-D, cordycepin, 5-fluorouracil and cycloheximide. The inhibitory effect was evident when the inhibitors were applied during the first 2–3 d of culture. During this period, extensive incorporation of radioactive leucine to protein and rapid increase in protein contents were observed in superficial layers of the stem segments cultured on the medium contaning benzyladenine (BA). The rapid increase in protein contents may be attributed to the inhibition of protein degradation by BA. The turnover rates of proteins in superficial layers of the explants cultured with or without BA for 3 d were 2.2 and 4.7% per h, respectively. The SDS-polyacrylamide gel electrophoretic profile of labelled proteins in superficial layers of the explants cultured on BA-containing medium resulted in some differences to the one obtained from the hormone-free medium.