A COMPARISON OF THE SYNTHESIS OF DNA, RNA AND PROTEINS IN THE EMBRYOSOF AFTER-RIPENED AND THERMO-DORMANT OR FR-DORMANT AGROSTEMMA-GITHAGO L SEEDS

Imbibed embryos of after-ripened and secondarily thermo- and FR-dorman t Agrostemma githago seeds were investigated as to their ability to sy nthesize DNA, RNA and proteins with the aim of finding characteristic differences connected with the induction and maintenance of developmen tal arrest. A gradual decrease in DNA synthesis was observed during th e induction of thermodormancy. However, DNA synthesis was stimulated u p to that of embryos of 30-h-imbibed after-ripened seeds within 24 h a pproximately after transferring the thermodormant seeds into temperatu res which normally allow germination. DNA synthesis of embryos of FR-d ormant seeds remained constant at a relatively low level during 7 d FR and another 7 d dark incubation. RNA synthesis decreased to different extents during induction of thermo- and FR-dormancy when it was arres ted at a relatively low level in seeds transferred to temperatures whi ch normally allow germination. Processes leading to an increase in RNA synthesis such as in embryos of after-ripened seeds appeared to be qu antitatively and/or qualitatively repressed. Interestingly, protein sy nthesis was extremely depressed during induction of thermodormancy whe reas it was slightly stimulated during induction of FR-dormancy. Never theless two-dimensional protein PAGE revealed several polypeptides whi ch were new, increased, decreased or not synthesized predominantly in axes of thermo- and FR-dormant seeds in comparison to germinating afte r-ripened seeds. It is suggested that a connection exists between thes e polypeptides and the repression of germination. After transferring s econarily dormant seeds to temperatures which normally allow germinati on, a temporary stimulation of protein synthesis could be observed in both cases.