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（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。

Influences of Na2CO3 Stress on Physiological Metabolisms of Different Alkali Tolerant Varieties of Stevia rebaudiana

Objective] The research aimed to reveal physiological mechanisms of alkali tolerances of different Stevia rebaudiana varieties under alkali stress.Method] By using matrix culture method,the influences of Na2CO3 on chlorophyll content,malondialdehyde(MDA),superoxide dismutase(SOD),peroxidase(POD) and Proline(Pro) content of leaves from different alkali tolerance varieties of S.rebaudiana No.2 Shoutian(relative alkali tolerance variety) and No.4 Zhongshan(alkali sensitivity variety)] were studied.Result] 1.2 g/L of Na2CO3 stress made that the chlorophyll contents of leaves from No.2 Shoutian and No.4 Zhongshan seedlings both decreased in different degrees.Moreover,MDA content of No.4 Zhongshan was higher than control during the whole stress period,and the largest increase amplitude was 43.2%.MDA content of No.2 Shoutian was lower than control in early and latter periods of stress,and increased the maximum on the 14th day of alkali stress,which was 24.4% higher than control.SOD activities of No.2 Shoutian and No.4 Zhongshan both showed a trend of first increasing and declining then in the alkali stress period,but the increasing extent of SOD activity in No.2 Shoutian was higher than that in No.4 Zhongshan.In latter period of Na2CO3 stress,SOD activity of No.2 Shoutian declined,but POD activity was higher than that of No.4 Zhongshan.It illustrated that POD had stronger scavenging capability of active oxygen.Pro contents of No.2 Shoutian and No.4 Zhongshan were higher than control in the stress period.It showed that the osmoregulation of Pro might not be key regulatory factor of alkali tolerance difference of the two S.rebaudiana varieties.Conclusion] The research not only provided theoretical basis for further breeding new salt tolerance variety of S.rebaudiana,but also had important significance for improving utilized ratio of kaline soil and growing environment for mudflat in China.