Bolting Hormone Regulation And Metabolomics Research On Vernalization Of Chinese Cabbage

Chinese cabbage is one kind of brassica vegetable crops. In the process of production, it tends to be immature bolting, which leads to low yields. And on the other hand, plant breeding needs different Chinese cabbage varieties bolting at the same time. Many factors interact with each other and ultimately affect phenotypes, and metabolites is the closest to phenotypes. The research of metabolites can contribute to reveal the direct causes of phenotypes and the function of related genes.To explore the dynamic changes of endogenous hormones in Chinese cabbage and its relationship with development, we harvested samples in different growth period of different Chinese cabbage varieties planted in field, and used enzyme-linked immunoassay to detect levels of gibberellic acid(GA3), auxin(IAA) and abscisic acid(ABA). The results showed that the content of endogenous hormones was different in different stages and varieties. ABA may play a key role in the process of bolting. Sharply increased ABA content can promote the process of bolting. In addition, GA3 content is relatively low in strong winter varieties. While, a high GA3 content may help to bolt in bolting stage.To solve the problem of flowering asynchronism in plant breeding, single factor experiment and orthogonal test were combined to explore the effects of paclobutrazol and gibberellin on bolting and flowering in different varieties of Chinese cabbage. The results showed that the bolting and flowering time of early bolting varieties could be postponed well by 100 mg?L-1 PP333, and treatment with 600 mg?L-1 GA3 once after transplanted 20 days was the best treatment combination for late bolting varieties.These two kinds of processing combination could make the winter different varieties flower at the same time. The results play a significant role in plant breeding.To explore the influences of vernalization and abscisic acid(ABA) treatment on Chinese cabbage, to illuminate the metabolic bases of freezing tolerance and the characteristics of metabolites of vernalization, to find the connections between varieties and metabolic profile, and to provide a quick and effective way to identify fine variety, we detected the metabolites.The metabolites were analyzed by the technique of Gas Chromatography-Mass Spectrometer(GC-MS) during a 30-day cold acclimation and a 10-day normal temperature treatment, and treatment with 20 mg?L-1 ABA was also be adopted. The metabolite profiling of two cabbage varieties suggested that the concentration of soluble sugars, amino acids and organic acids had a strong change under low temperature. The metabolites rapidly returned to normal when temperature increased. The variation tendency of metabolite with ABA treatment was similar to that with low temperature treatment. However the content was obviously different. The metabolite profiling of different varieties were discrepant. The metabolite profiling proved that ABA couldn’t induce the same cold acclimation as low temperature did; freezing tolerance of plants which had gone through cold acclimation will lose at a short time when temperature increases; the variety whose metabolite was affected slightly and protective agents increased quickly will have a stronger freezing tolerance when plants are put in the condition of low temperature. This study not only can provide basic data to understand cold stress, but also can provide a quick and effective way to identify fine varieties.