3种丁香叶片的PSⅡ光化学活性及光能利用特点

PSⅡ Photochemical Activity and Light Energy Utilization in Leaves of Three Clove Varieties

以我国北方地区常见的3种丁香属植物紫丁香(Syringa oblata)、白丁香(S.oblata var.alba)和暴马丁香(Syringa reticulata(Blume)H.Hara)为试验材料,利用快相叶绿素荧光动力学技术研究3种丁香叶片的PSⅡ光化学活性之间的差异。结果表明:3种丁香叶片Fv/Fm之间差异不大,但暴马丁香叶片的Fv/Fo和PIABS却小于紫丁香和白丁香,达到极显著差异水平,说明暴马丁香叶片的PSⅡ光化学活性相对较低。暴马丁香叶片PSⅡ电子受体侧电子由Q_A向Q_B传递的速率明显低于紫丁香和白丁香,而且Q_A^-向Q_B传递速率也明显低于紫丁香和白丁香,但3种丁香叶片Sm无显著差异,即在PQ库容量差异较小情况下,暴马丁香叶片Q_A向Q_B传递速率较低的原因与Q_B接受电子能力较低有关,受Q_B下游PQ库的影响较小。暴马丁香叶片放氧复合体OEC的功能和类囊体膜结构的稳定性也明显低于紫丁香和白丁香。虽然暴马丁香单位反应中心吸收的光能ABS/RC明显高于紫丁香和白丁香,但是3种丁香叶片的ET_o/RC之间却无显著差异,但DIo/RC极显著高于紫丁香和白丁香。因此,暴马丁香叶片PSⅡ反应中心能量分配的不均衡性也是其PSⅡ反应中心光化学活性较低的原因之一。

In this paper,the difference of PS Ⅱ photochemical activity in the three kinds of leaves of Syringa oblata,S. oblata var. alba and Syringa reticulata（ Blume） H. Hara from Northeast China was investigated by using chlorophyll fast fluorescence technique. The results showed that there was no significant difference among the Fv / Fm in three kinds of leaves. However,the Fv / Fo and PIABSin Syringa reticulata（ Blume） H. Hara were significantly lower than that in Syringa oblate and S. oblata var. alba. PSⅡphotochemical activity in Syringa reticulata（ Blume） H. Hara was relatively low. The transfer rate from Q_A to Q_B in PS II electron acceptor side in Syringa reticulata（ Blume） H. Hara was obviously lower than that in Syringa oblate and S. oblata var. alba,and the transfer rate from Q-Ato Q_Bwas the same as Q_Ato Q_B,but Smwas not significantly different among the three kinds of varieties. It was suggested that the low transfer rate from Q_Ato Q_Bin Syringa reticulata（ Blume） H. Hara was related to the low capability of Q_Baccepting electron under less difference of the PQ library capability,and that was less affected by PQ library at Q_Bdownstream. The function of oxygen evolving complex（ OEC） and the stability of thylakoid aggregation structure in the Syringa reticulata（ Blume） H. Hara was significantly lower than that in Syringa oblate and S. oblata var. alba,and light absorption by unit reaction centre ABS / RC was apparently higher than that in Syringa oblate and S. oblata var. alba. However,there was no significant difference between the ETo/RC in the three kinds of leaves,but DIo/ RC in Syringa reticulata（ Blume） H. Hara was greater significantly than that in Syringa oblate and S. oblata var. alba oppositely. Therefore,the imbalance of energy distribution of PSⅡ reaction centre was one of the reasons that led to the decrease of the photochemical activity of PSⅡ reaction centre.