| The non-heading Chinese cabbage, tender texture, nutritious, which plays an important role in vegetable consumption, is a kind of widely cultivated vegetable in southern China. Seed quality has greatly effects to crop yield and quality. The seed vigor is a reliable index to measure seed quality. Seed processing, storage and even sowing, can lead to decrease even disappearance of the seeds activity, and the seed vigor would have effects on seeds' germination, plant growth, yield and quality after sowing. Priming technology can increase seed vigor, germination capacity and resistance ability to stress after germination. therefore, we can use the chemical reagents to prming the non-heading Chinese cabbageIn view of the rarely report of the studies of non-heading Chinese cabbage seed priming, the non-heading Chinese cabbage cultivar 'Shu Lv' and 'Han Xiao' seeds were selected as materials to study the different priming treatments on the non-heading Chinese cabbage seed germination and physiological characteristic, and the quality of resistance against high temperature and salt stress of the priming sees. Explore the effects and mechanism of priming treatments, so as to provide theoretical basis for application of priming treatment in non-heading Chinese cabbage cultivation. The main results were as follows:1. In the chloride ion, phosphate ion and nitrate ion chemical initiator, and the priming effects of chloride salt solution were similar to the nitrate salt solution, both of them showed better priming effects than that of the phosphate ion salt solution. The priming effect of 1% CaCl2 among chloride salt solution was better, 'Shu Lv' germination energy and germination rate reached 90.67% and 94.67%, respectively; 'Han Xiao' germination energy and germination rate were both up to 85.33%, and their germination index and vigor index significantly exceeded control and other treatments; In Nitrate salt solution, germination energy, germination rate, germination index and vigor index of 0.5% KNO3 were significantly higher than that of the control and other treatments, the germination energy and germination rate of 'Shu Lv' reached 90.00% and 90.67%,and which of 'Han Xiao'came up to 88.00% and 92.00% respectively; while the priming effects of the phosphate ion salt solution (except 1% KH2PO4) were not ideal; Different concentrations of PEG priming treatment significantly increased the seed germination energy, germination rate and vigor index, but has no significant effect on germination index. Comprehensive comparison of the effects of various chemical initiators on seed germination,1% CaCl2 came first,0.5% KNO3 ranked second, and then followed 10% PEG, while K3PO4 has the worst priming effect, leading to the abnormal germination of seeds.2. After the different priming treatment, on the standard condition, the two non-heading Chinese cabbage seed's germination energy(except 10% PEG), germination rate(except 10% PEG), germination index and vigor index were significantly beyond control and other treatments. The different priming treatments have effect on the non-heading Chinese cabbage seed physiological characteristic and aactive oxygen metabolism.1% CaCl2 priming treatment significantly increased the'Shu Lv' and 'Han Xiao' seed soluble sugar, soluble protein, proline content and SOD, POD, CAT antioxidant enzyme activity, significantly reduced the O2·production rate, malondialdehyde content, the relative conductivity and APX activity. Therefore, compared to the other chemical agents,1% CaCl2 has the most significant effect on seed germination. It not only improved the germination characteristics of seeds, but also played a significant role on seed's active oxygen metabolism.3. High temperature and salt stress have a certain inhibitory effects on seed germination, but after CaCl2 priming treatment, the seed germination characteristics index (except the germination index and vigor index in salt stress condition) of two varieties of the non-heading Chinese cabbage were significantly increased. During 7 consecutive days of seedling growth, compared with the corresponding control, priming treatment increased soluble protein content, SOD, POD and CAT activity of the non-heading Chinese cabbage seedling, reduced the O2-·production rate, malondialdehyde content, relative electrical conductivity, proline content and APX activity under different germination conditions, showing significant effects on the third day. Therefore, during the whole seedling growth, after CaCl2 priming treatment, compared with the corresponding conditions, the germination characteristics of protective enzymes and osmotic adjustment, etc. have shown a clear advantage of the non-heading Chinese cabbage, to a certain extent, could relieve stress on the plant damage. In the high temperature and salt stress condition, the non-heading Chinese cabbage have the most positive response to stress on the third day during the seedling growth.4. After priming treatments, the two varieties of the non-heading Chinese cabbage seed germination energy, germination rate and vigor index were significantly higher than that of the control.1% CaCl2 priming significantly increased the seed germination rate, emergence rate, plant height, leaf number, spreading, overground plant fresh weight and overground plant dry weight, significantly increased plant Vc, soluble sugar and soluble protein content, and significantly reduced the nitrate content. The yield of non-heading Chinese cabbage was significantly increased. Therefore,1% CaCl2 can be used as the most appropriate priming reagent of the seeds of non-heading Chinese cabbage, and the seeds treated by 1% CaCl2 can be directly sow in the field, which have fast emergence rate and high yield,was also an alternative to transplant and cost saving. |
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