The Vernalization Of Chinese Cabbage And Its Biochemical-Physiology

Vernalization is the key factor which controls the process of Chinese cabbage from vegetable growth to reproduction growth. In order to provide a theorestic foundation for bolting resistance breeding of Chinese cabbage, the budding of several Chinese cabbage cultivars with different bolting tolerance were observed after treated at seedling stage in the low temperature for different days, and the changing of biochemistry and physiology in germinated seeds and seedlings of Chinese cabbage during treated in low temperature were measured,The results were as follows:1 The observation of budding of the Chinese cabbage after treated in 4-5℃for different days shows that the Chinese cabbage with different bolting tolerance need different days treatment of the 4-5℃low temperature for vernalization,the weaker of winterness of it is the fewer of low temperature requirement; As the time of vernalization is increased, the time of budding occurs earlier and the duration of budding is shorted. The different seedlings of Chinese cabbage have different sensibility to low temperature, The seedling of 4-5 leaves stage was most sensitive to low temperature, the junior or older seedling were less sensitive, and 2-3 leaves stage is more sensitive than 7-8 leaves stage, but the seedling ages have not significant influence to the starting time of budding; It also found that the illumination during low temperature treatment is need for finishing vernalization and budding.2 From the budding observation of three Chinese cabbage with different bolting tolerance after treated under 4-5℃low-temperature by interrupted for 2 days, 3 days, 4 days and 5 days, it was found that: as the interregnum is prolonged, the average budding or flowering date were delayed and the duration of budding or flowering is prolonged. It was also found that the state of plant vernalization when interrupted affect the interrupted effectiveness, as the longer time of vernalization when interrupted, the earlier budding of it. This may indicate that the vernalization result is closely related to the vernalization time before interruption.3 Different bolting tolerance Chinese cabbage plants were vernalized under 4-5℃low-temperature, during vernalization the NR(Nitric Acid Reductase)activity kept a low level at the beginning 22 days,the NR activity increased rapidly during 22-36 days, after 36 days dropped rapidly again, the rapid increasing of NR activity is not closely related to the vernalization, but closely related to the accumulation of low-temperature. More than 15 days low-temperature control can restrain ASP activity increased; The activity of POD and COD in Chinese cabbage plants dropped rapidly after 5 days low-temperature control, But there were no special bands of POD and COD isozyme were appeared among species; During verbalization, the change of content of soluble protein is activityly and it fluctuate unceasingly, but in different species the difference of content of soluble protein is not obvious.The NR activity in Chinese cabbage dropped and the ASP activity and content of soluble protein increased during vernalization without light. Furthermore, different bolting tolerance Chinese cabbage plants has the different influence to it, strong bolting tolerance Chinese cabbage is more sensitively.4 The NR(Nitric Acid Reductase)activity in germinated seeds of Chinese cabbages is closely relative to bolting tolerance of Chinese cabbages, before vernalization the NR activity in the strong bolting tolerance Chinese cabbages is the 3-4 times than in the weak bolting tolerance ones; During vernalization at 2℃, the NR activity dropped at first then increased slowly in strong bolting tolerance Chinese cabbage, in the weak bolting tolerance ones the change tendency is oppositely;The change tendency of content of soluble protein during verbalization is going as inverse"S"curve. Specific protein bands for each Chinese Cabbages were detected at the end of vernalization. Since vernalization for twenty days, the activity of POD and COD increased, and new bands of POD and COD isozyme were appeared but the commonβ-EST isozyme which Rf is 0.632 and existed in them before this time is disappeared.