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[目的]探讨不同甜菊(Stevia rebaudiana)品种在碱胁迫下耐碱的生理机理。[方法]采用基质培养方法,研究了Na2CO3对不同耐碱性甜菊品种守田2号(相对耐碱型)和中山4号(碱敏感型)叶片叶绿素、丙二醛(MDA)、超氧化物歧化酶(SOD)、过氧化物酶(POD)酶和脯氨酸生理代谢的影响。[结果]1.2g/L Na2CO3碱胁迫均使守田2号和中山4号幼苗叶片叶绿素含量不同程度降低,且中山4号在整个胁迫期内MDA含量均高于对照,增幅最大为43.2%,守田2号MDA含量在胁迫初、末期低于对照,在碱胁迫14d时MDA含量最高,比对照增加24.4%。守田2号和中山4号碱胁迫期间SOD活性均表现出先增后降的趋势,但相对耐碱的守田2号叶片SOD活性增幅高于碱敏感型甜菊中山4号,胁迫后期守田2号SOD活性降低,但POD活性高于中山4号,说明此时POD具有较强的活性氧清除能力。耐碱甜菊守田2号和相对碱敏感甜菊中山4号在胁迫期内叶片脯氨酸含量均高于对照,表明脯氨酸的渗透调节可能不是2种甜菊耐碱能力差异的关键调节因子。[结论]不仅为进一步选育甜菊耐盐新品种提供了理论依据,同时对提高我国盐碱地利用率、改善滩涂立地环境具有重要意义。
[Objective] The research aimed to discuss the physiological mechanism of alkali-resistance of different varieties of Stevia rebaudiana. [Method] The effects of Na2CO3 on chlorophyll, malondialdehyde (MDA), superoxide dismutase (SOD) and malondialdehyde (SOD), peroxidase (POD) enzymes and proline physiological metabolism. [Result] The chlorophyll content of seedling leaves of Shoutian 2 and Zhongshan 4 decreased under different alkali treatments under 1.2g / L Na 2 CO 3, and the content of MDA in Zhongsha 4 was higher than that of the control at the maximum, 43.2% The MDA content of No.2 was lower than that of the control at the beginning and the end of stress, and the content of MDA was the highest at 14 d after alkali stress, increasing by 24.4% compared with the control. The activities of SOD increased first and then decreased during alkali stress in both Shoutian 2 and Zhongshan 4, but the SOD activity in the leaves of the supper alkali-tolerant Shaotian 2 was higher than that of the alkali-sensitive Stevia Zhongshan 4, and the superoxide dismutase SOD2 Decreased, but the activity of POD was higher than that of Zhongshan No.4, indicating that POD had a strong capability of removing reactive oxygen species. The content of proline in leaves of alkali tolerant Stevia Shoutian 2 and relative alkali-sensitive Stevia rebaudiana 4 was higher than that of the control, indicating that the regulation of proline penetration may not be the key regulator of the difference in the two alkali tolerance of Stevia rebaudiana. [Conclusion] It not only provided theoretical basis for further breeding of new varieties of stevia tolerant to salt, but also played an important role in improving the utilization of saline-alkali land and improving the site-setting environment of the beaches.