水分胁迫对小麦捕光色素蛋白复合物的影响

Effects of water stress on the light-harvesting complexes in wheat leaves

棉农 4号春小麦幼苗 (Triticum aestivum L.cv.Miannong No.4)经 - 0 .5MPa PEG溶液渗透胁迫 2 4、48和 72 h,使叶片分别受到轻度、中度和重度的水分胁迫。在此渐进水分胁迫条件下 ,叶绿体类囊体膜中光系统 捕光色素蛋白复合物 (LHC )的各组分含量发生了不同变化。对类囊体膜色素蛋白复合物进行的温和电泳结果显示 ,在轻度水分胁迫 (2 4 h)时 ,三聚体形式的 LHC b含量有所增加 ,而在中度 (48h)和重度 (72 h)胁迫下其含量减少 ,说明轻度水分胁迫对其有诱导作用 ,而中、重度水分胁迫对它有破坏作用。与 L HC b的变化不同 ,LHC a和 LHC c的含量在轻度水分胁迫时就开始下降 ,LHC d的含量在整个胁迫过程中变化不大。讨论了 LHC 各组分在水分胁迫下发生不同变化的原因。

Osmotic dehydration of wheat seedlings ( Triticum aestivum L.cv.Miannong No.4) in -0.5 MPa PEG solutions for 24,48 and 72 h,resulted in mild,moderate and severe water stress in leaves,respectively.This progressive water stress gave rise to different changes in contents of the components of the light harvesting complexes of photosystem Ⅱ(LHC Ⅱ) in thylakoids.Green gel electrophoresis of thylakoid pigment protein complexes showed that the levels of LHC Ⅱb was induced by mild water stress but decreased by moderate and severe stresses.Unlike LHC Ⅱb,the levels of both LHC Ⅱa and LHC Ⅱc decreased gradually throughout the stress treatment,while no apparent change in LHC Ⅱd level was observed.The possible reasons for different changes of LHC Ⅱ components during water stress were discussed.