中文摘要：

细胞外ATP（eATP）可作为一种重要的胞外分子调节植物的多种生理反应。该研究以菜豆（Phaseolus vulgaris L.）品种‘农普12号’幼苗叶片为实验材料,研究了胞外1.0mmol/L ATP溶液对低温下（10℃、10h）菜豆叶片光系统Ⅱ（PSⅡ）运行及光能分配的影响。结果显示：（1）低温胁迫（10℃、10h）对菜豆叶片PSⅡ的潜在最大光化学效率（F_v/F_m）没有产生显著性影响,但低温胁迫却降低了叶片的实际光化学运行效率[Y（Ⅱ）],同时降低了PSⅡ的光化学反应能量（P）,增加了天线热耗散能量（D）和非光化学反应耗散能量（E）,使叶片胞外ATP水平有所下降。（2）叶片施加外源ATP可以有效缓解低温胁迫下菜豆叶片胞外ATP水平的下降,同时使叶片的实际光化学效率[Y（Ⅱ）]和光化学反应能量（P）显著上升,也使天线热耗散能量（D）非光化学反应耗散能量（E）均显著下降。研究表明,低温胁迫降低了菜豆叶片PSⅡ的光化学运行并增加了光能的耗散,而在低温胁迫下增加胞外ATP水平能够有效提高菜豆叶片光化学反应的运行效率并降低光能的耗散。

英文摘要：

It has been established that extracellular ATP（eATP）is an important extracellular molecule required to regulate many physiological responses of plants.This study investigates the effects of eATP on the operation of photosystem Ⅱand the allocation of absorbed light of bean（Phaseolus vulgaris L）leaves under low temperature.The results showed that although low temperature did not have significant effect on the potential maximal photochemical efficiency of PSⅡ（F_v/F_m）,low temperature decreased the values of the effective photochemical quantum yield of PSⅡ [Y（Ⅱ）].Further works showed that low temperature decreased the fraction of photochemical efficiency（P）but increased the fraction of antenna heat dissipation（D）and excess energy（E）.The level of eATP decreased under low temperature.When the application of exogenous ATP alleviated the decreases of the eATP level under low temperature,the values of Y（Ⅱ）and P were significantly increased,while the values of Dand E were decreased.These results indicate that low temperature caused a decrease in the operation of the PSⅡ photochemistry and caused an increase in dissipation of light energy,and eATP could have function in enhancing the performance of PSⅡ photochemistryand decreasing the dissipation of light energy under the condition of low temperature.