高温下两种不同生态型麻疯树叶片光能利用和分配特性的比较

比较了高温对来源于海南和贵州的2种不同生态型麻疯树的光能利用和分配特性的影响.结果表明，温度升高引起了2种麻疯树叶片PSⅡ最大光能转化效率（Fv/Fm）的降低和初始荧光（Fo）的上升，部分抑制了PSⅡ的功能.与贵州麻疯树相比，海南麻疯树在中度高温胁迫（30～40℃）时，增加了对过量激发能的热耗散能力，使其维持较高的光能转化效率.当温度升至45℃，虽然热耗散机制受到破坏，海南麻疯树仍然有7%的光能用于光化学反应，而贵州麻疯树的这一比例降为0%.本研究的结果表明，海南麻疯树比贵州麻疯树具有更强的高温耐受能力.

COMPARISON OF THE ALLOCATION OF ABSORBED LIGHT ENERGY IN LEAVES BETWEEN TWO DIFFERENT ECOTYPES OF PHYSIC NUT(JATROPHA CURCAS L.) UNDER HIGH TEMPERATURE

The changes in utilization and allocation of absorbed light energy in two ecotypes of Jatropha curcas originally growing in Hainan Province and Guizhou Province were examined under high temperature. Exposure to high temperature caused a decrease in maximum quantum efficiency of photosystem Ⅱ photochemistry (Fv/Fm) and an increase in primary fluorescence (Fo) of both two ecotypes of J. curcas, suggesting that photosystem Ⅱ function was inhibited partially by high temperature stress. In comparison with Guizhou ecotype, Hainan ecotype showed more increasing heat dissipation fraction of excess excitation energy and maintained higher light energy conversion efficiency under moderate high temperature (30-40℃). At 45℃, the mechanism of heat dissipation was being destroyed; Hainan ecotype still allocated 7% absorbed light to photochemical reaction, while that in Guizhou ecotype was completely loss (0%). The present result suggested that J. curcas from Hainan Province has greater tolerance responding to short term high temperature exposure than that from Guizhou Province.