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为研究白菜型冬油菜的耐盐机制,以耐盐材料KY-1、KY-191和盐敏感材料NDJ为材料,采用NaCl模拟法,研究了盐胁迫对白菜型冬油菜种子萌发和幼苗生理特征、离子稳态、光合特性等的影响。结果表明:盐胁迫显著抑制白菜型冬油菜种子萌发、胚根和胚芽伸长,胚根伸长对盐胁迫更为敏感;盐胁迫下耐盐品系KY-1、KY-191种子萌发优于盐敏感品系NDJ。随着盐胁迫程度加深,幼苗叶片游离脯氨酸含量、电导率、MDA含量逐渐上升,抗氧化酶SOD、POD、CAT活性呈先升高后降低趋势;且耐盐品系抗氧化酶活性、游离脯氨酸含量高于盐敏感品系,而电导率、MDA含量均低于盐敏感品系。盐胁迫下幼苗Na+含量升高,K+含量降低;光合色素含量显著下降,但耐盐品系KY-1、KY-191下降幅度小于盐敏感品系NDJ;各品系蒸腾速率Tr、气孔导度Gs、光合速率Pn明显下降,胞间CO2浓度Ci显著升高。综上所述,盐胁迫下白菜型冬油菜耐盐品系通过K+积累缓解Na+毒害;渗透调节物含量提高抵御离子水势胁迫;能够维持较良好的胞内生理状态和保持较强的光合能力。
In order to study the mechanism of salt tolerance in Brassica campestris, salt tolerant materials KY-1, KY-191 and salt-sensitive material NDJ were used to study the effects of salt stress on seed germination and seedling physiological characteristics of Brassica campestris , Ion homeostasis, photosynthetic characteristics and so on. The results showed that salt stress significantly inhibited the seed germination, radicle and germination elongation, and the elongation of radicle was more sensitive to salt stress. The salt-tolerant KY-1 and KY-191 seed germination was better than salt Sensitive strain NDJ. With the deepening of salt stress, free proline content, electrical conductivity and MDA content of seedling leaves increased gradually, and the activities of SOD, POD and CAT increased first and then decreased, and the activities of antioxidant enzymes, free Proline content was higher than the salt-sensitive strains, while the conductivity and MDA content were lower than the salt-sensitive strains. Under salt stress, the contents of Na +, K + and K + in seedlings decreased, while the content of photosynthetic pigments decreased significantly. However, the decline of KY-1 and KY-191 was less than that of salt-sensitive lines NDJ. Transpiration rate Tr, stomatal conductance Gs, photosynthesis The rate Pn decreased obviously, and the intercellular CO2 concentration Ci increased significantly. In summary, salt tolerant strains of Brassica campestris yielded alleviating Na + toxicity through K + accumulation; osmotic regulators increased resistance to ionic water potential stress; maintained good intracellular physiological state and maintained strong photosynthetic capacity.