高温对入侵种三裂叶蟛蜞菊叶片PSII功能和光能分配的影响

Effects of High Temperature on the PSII Functions and Absorbed Light Allocation in Leaves of Invasive Wedelia trilobata

以入侵植物三裂叶蟛蜞菊及其近缘本地种蟛蜞菊为实验材料,比较高温对二者PSII功能和光能分配特性的影响。结果显示,三裂叶蟛蜞菊PSII最大光能转化效率(Fv/Fm)受高温抑制的程度较轻,初始荧光(Fo)上升幅度较小。高温胁迫降低了三裂叶蟛蜞菊叶片总的光合电子传递速率(JF),但它同时降低了电子流向光呼吸分配的比例(Jo/JF),相对提高了电子流向碳同化的分配(Jc/JF)。与蟛蜞菊相比,高温处理后三裂叶蟛蜞菊仍然能够将较多吸收的光能用于光化学反应,以维持较高的碳同化水平。本研究的结果表明入侵植物三裂叶蟛蜞菊比本地种蟛蜞菊具有更强的耐高温能力,意味着入侵种三裂叶蟛蜞菊在全球气候变暖的环境背景下具有潜在的扩散优势。

Invasive Wedelia trilobata and its native congener W. chinensis were used as materials for comparison of their PSII functions and absorbed light allocation under high temperature. The results showed that high temperature suppressed maximum quantum efficiency of photosystem Ⅱ photochemistry （Fy/Fm） less in invasive W. trilobata, and primary fluorescence （Fo） in invasive W. trilobata increased slightly under high temperature stress. High temperature decreased photosynthetic electron transport rate （JF） and the ratio of total electron flow partitioned to photorespiration （Jo/JF） in W. trilobata, but increased relatively the ratio of total electron flow partitioned to carboxylative process （Jc/JF）. Compared to native congener W. chinensis, invasive W. trilobata could allocate a greater part of absorbed light to photochemistry reaction after high-temperature treatment, which was benefited to maintain higher level of carbon assimilation. Altogether, invasive W. trilobata has more tolerance to high temperature, implicating that it has the potential advantage in spread accompanying with global warming in the future.