中文摘要：

研究了细胞外ATP对菜豆叶片光系统Ⅱ（PSⅡ）光化学特性的系统性影响及可能的内在机制。研究发现,用外源ATP处理菜豆叶片的一侧,处理侧和同叶未处理侧潜在最大光化学效率（F_v/F_m）、非调节性能量耗散量子产量（Y（NO））与对照相比无显著变化;而实际光化学效率（Y（Ⅱ））、电子传递速率（ETR）和光化学猝灭系数（q P）与对照相比显著上升,但非光化学猝灭系数（q N）和调节性能量耗散量子产量（Y（NPQ））则显著下降。表明了细胞外ATP能够系统性地提高菜豆叶片PSⅡ光化学效率。用外源ATP处理菜豆叶片的一侧,检测叶片处理侧与同叶未处理侧过氧化氢的含量,发现与对照相比,叶片处理侧与未处理侧过氧化氢含量均显著上升。用外源过氧化氢（H2O2）处理菜豆叶片一侧也导致了处理侧与同叶未处理侧Y（Ⅱ）、ETR和q P的显著上升,以及q N和Y（NPQ）的显著下降。因此,过氧化氢和ATP能够对处理侧与同叶未处理侧叶片的光化学特性产生相似的影响。进一步研究表明,用过氧化氢的淬灭剂N,N＇-二甲基硫脲（DMTU,dimethylthiourea）可以减弱ATP对菜豆叶片处理侧与未处理侧Y（Ⅱ）、ETR、q P、q N和Y（NPQ）产生的影响。这些结果表明：菜豆叶片局部细胞外ATP的增加可加强邻近组织PSⅡ的光化学效率,并且胞外ATP对叶片PSⅡ光化学特性的这种系统性影响依赖于H_2O_2调节的下游信号途径。

英文摘要：

We studied the systemic effects of extracellular ATP（ e ATP） on the Photosystem Ⅱ photochemistry of kidney bean（ Phaseolus vulgaris） leaf and possible mechanism for this effect. Treatment of a half of a bean leaf with exogenous ATP had no significant effect on the maximal photochemical efficiency of photosystem Ⅱ（ F_v/ F_m）,and the quantum yield of non-regulated energy dissipation（ Y（ NO）） of the treated half and the untreated,opposite half of the same leaf. However, this treatment significantly increased the values of photochemical efficiency（ Y（ Ⅱ））,the rate of photosynthetic electron transport（ ETR）,and photochemical quenching（ q P）,while the values of the non-photochemical quenching（ q N） and the quantum yield of regulated energy dissipation（ Y（ NPQ）） were significantly decreased by exogenous 1 mmol·L- 1ATP. These observations indicate that e ATP can function in systematically enhancing the PS Ⅱ photochemistry of kidney bean leaves.Treatment of a half of a bean leaf with exogenous ATP,we tested the change of the oxidation hydrogen content of the treated half and the untreated,opposite half of the same leaf. Compared to the control,hydrogen peroxide content of the treated half and the untreated,opposite half of the same leaf were significantly increased. Similar to the effects of exogenous ATP,treatment with exogenous H_2O_2 at 1 mmol · L- 1also led to a significant increase in Y（ Ⅱ）,q P and ETR and a significant decrease in q N and Y（ NPQ） of the treated half and the untreated,opposite half of the same leaf. DMTU（ dimethylthiourea,a scavenger of H_2O_2） weakened the effectsof exogenous ATP on the Y（ Ⅱ））,q P,ETR,q N and Y（ NPQ）. These observations indicate that an increase in e ATP concentration of partial region of bean leaf can enhance the PSⅡ photochemistry of the adjacent tissues,and such function of e ATP could be dependent of H_2O_2.