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Effects of Photoinhibition and Its Recovery on Photosynthetic Functions of Winter Wheat Under Salt Stress


Effects of photoinhibition and its recovery on photosynthetic functions of winter wheat ( Triticum aestivum L.) under salt stress were studied. The results showed that several parameters associated with PSⅡ functions, e.g. Fv/Fo 、 Fv/Fm and qP were not influenced by lower salt concentration (200 mmol/L NaCl) while CO2 assimilation rate decreased significantly. When exposed to higher salt concentration (400 mmol/L NaCl), PSⅡ functions were significantly inhibited which led to the decrease of carbon assimilation. These results suggest that different concentrations of salt stress affected photosynthesis by different modes. Salt stress made photosynthesis more sensitive to strong light and led to more serious photoinhibition. Under lower concentration of salt stress, the QB-non-reductive PSⅡ reaction centers formed at the beginning of photoinhibition could be effectively used to compose active PSⅡ reaction center (RC) and repair the reversible inactivated PSⅡ RC. Under higher concentration of salt stress, PSⅡ reaction centers were seriously damaged during photoinhibition, the QB-non-reductive PSⅡ RC could only be partly effective at the early time of photoinhibition, thus led to the accumulation of QB-non-reductive PSⅡ RC in the course of restoration under dim light.

在盐胁迫下光抑制及其恢复进程对冬小麦光合功能的影响
朱新广 王强 张其德* 卢从明 匡廷云
(中国科学院植物研究所光合作用基础研究开放实验室,北京100093)

摘要:研究了盐和强光双重胁迫以及在弱光下恢复对冬小麦(Triticum aestivum L.)光合功能的影响.结果表明,单纯用低浓度盐(200 mmol/L NaCl)胁迫时,对反映PSⅡ光合功能的Fv/Fo、Fv/Fm和qP等参数没有什么影响,但已十分明显地抑制光合碳同化能力,而高盐(400 mmol/L NaCl)胁迫损伤PSⅡ功能,从而加剧对碳同化功能的抑制,说明光合作用对不同盐浓度的响应不同.研究结果还表明,盐胁迫能加剧强光对光合功能的损伤,使之受到更加严重的光抑制.在低盐浓度下,光抑制初期形成的QB-非还原性PSⅡ反应中心,在随后的光抑制进程和弱光下恢复期间,能有效的被用来合成有活性的PSⅡ和修复可逆性失活的PSⅡ反应中心.而高盐和强光双重胁迫使PSⅡ遭受严重破坏,QB-非还原性PSⅡ反应中心只有在光抑制初期可部分地用于修复可逆性失活的PSⅡ,随着光抑制的进程,它们不能用于合成有活性PSⅡ和修复受严重破坏的PSⅡ,结果导致它们的含量在弱光下恢复时继续增加.
关键词: 冬小麦;盐胁迫;光抑制


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