Histological and Physiological Changes in the Process of in vitro Shoot Regeneration from Cotyledons of Chinese Cabbage

Aichi Hakusai(C₁),which was a Chinese cabbage cultivar(Brassicarapa ssp.pekinensis(L.)Olsson)introduced from Japan,was used as plant material in this experiment.Investigations were carried out on histological and physiological changes during the process of in vitro shoot regeneration from cotyledonary explants.Histological observations showed that,(adventitious)shoots were induced through the pathway of direct organogenesis during the process of explants culture.Before adventitious shoots initiated,soluble protein content and activities of POD and SOD showed the trend to increase.As the cells were dedifferentiated,metabolism activity of cells gradually became stronger;enzymes activity and the soluble protein content were elevated.These results demonstrated that,morphological changes were strongly associated with physiological changes during the process of adventitious shoot induction.Addition of AgNO₃ to the medium increased the activity of enzymes and promoted the differentiation percentage of(adventitious)shoots.