Na2CO3胁迫对甜菊不同碱耐性品种生理代谢的影响

目的]探讨不同甜菊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）和脯氨酸生理代谢的影响。结果]1.2 g/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含量在胁迫初期和末期低于对照,在碱胁迫14 d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碱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。

Influences of Na2 CO3 Stress on the Physiological Metabolisms of Different Stevia rebaudiana Alkali Tolerance Varieties

Objective] The research aimed to discuss the physiological mechanisms of alkali tolerances of different Stevia rebaudiana varieties under the alkali stress.Method] By using the matrix culture method,the influences of Na2CO3 on leaf chlorophyll content,malondialdehyde(MDA),superoxide dismutase(SOD),peroxidase(POD) and Pro content of different S.rebaudiana alkali tolerance varieties Shoutian No.2(relative alkali tolerance variety) and Zhongshan No.4(alkali-sensitive variety)] were studied.Result] The alkali stress of 1.2 g/L of Na2CO3 made that the chlorophyll contents of Shoutian No.2 and Zhongshan No.4 seedlings both decreased to some extent.Moreover,MDA content of Zhongshan No.4 was higher than the control during the whole stress period,and the largest increase range was 43.2%.MDA content of Shoutian No.2 was lower than the control in early and end periods of stress,and increased the maximum on the 14th day of alkali stress,which was 24.4% higher than the control.SOD activities of Shoutian No.2 and Zhongshan No.4 both showed a trend of first increasing and declining then in the alkali stress period,but the increasing extent of SOD activity in Shoutian No.2 was higher than that in Zhongshan No.4.In late stage of Na2CO3 stress,SOD activity of Shoutian No.2 declined,but POD activity was higher than that of Zhongshan No.4.It illustrated that POD had the strong scavenging capacity of reactive oxygen.Pro contents of Shoutian No.2 and Zhongshan No.4 were higher than the control in the stress period.It showed that the osmotic adjustment of Pro may not be key regulatory factor of alkali tolerance difference for the two kinds of S.rebaudiana.Conclusion] The research not only provided the theoretical basis for further breeding the new alkali tolerance variety of S.rebaudiana,but also had the important significance for improving the utilized ratio of kaline soil and environment for beach site in China.