外源ATP对NaCl胁迫下菜豆叶片叶绿素荧光特性的调节

盐胁迫是影响植物生长的主要逆境因子之一，外源ATP被发现可作为信号分子参与植物对逆境胁迫生理反应的调节。为了探明外源ATP在植物盐胁迫响应中的作用，以增强植物对土壤盐渍化的耐性，更好地应用于土壤盐渍化修复。该研究以菜豆( Phaseolus vulgaris)为材料，通过叶绿素荧光技术探讨了外源ATP 对菜豆叶片在NaCl胁迫下叶绿素荧光特性的变化规律。结果表明：在NaCl胁迫下，叶片光系统Ⅱ( PSⅡ)潜在最大光化学量子效率( Fv/Fm)、光适应下最大光化学效率( Fv′/Fm′)、PSⅡ光适应下实际光化学效率 Y (Ⅱ)]、光化学荧光猝灭( qP)、电子传递速率( ETR)与对照组相比均有显著性下降，而非光化学猝灭( NPQ)和( qN)较对照组有显著性增加，这表明NaCl胁迫导致菜豆叶片光系统Ⅱ光化学效率的下降和光能耗散的增加。而外源ATP(eATP)的处理能有效缓解NaCl胁迫所造成的Fv/Fm、Fv′/Fm′、Y(Ⅱ)、qP、ETR下降和NPQ、qN的上升。该研究结果表明在NaCl胁迫下外源ATP可以有效地提高菜豆幼苗光系统Ⅱ( PSⅡ)的光化学反应效率。

Effects of exogenous ATP on chlorophyll fluorescence characteristics of bean leaves under NaCl stress

NaCl stress is an important adverse environmental factor, exogenous ATP (eATP) was found a signal mole-cule involved in plant responses to stresses. We studied the effects of exogenous ATP ( eATP ) on chlorophyll fluores-cence characteristics of bean ( Phaseolus vulgaris ) leaves under NaCl stress. The results showed that treatment with NaCl caused a significant decrease in the ratio of Fv/Fm(the potential maximal photochemical efficiency of PSⅡ), Fv′/Fm′(the maximum quantum efficiency of PSⅡphotochemistry at illumination ), Y(Ⅱ)(effective photochemical quantum yield of PSⅡphotosynthetic), qP(photochemical quenching coefficient), and ETR(the rate of non-cyclic electron transport through PSⅡ), but the levels of qN(non-photochemical quenching) and NPQ(non-photochemical quenching) were significantly increased. These results suggested that NaCl stress caused the decrease of the photochemical efficiency of bean leaves and dissipation of light energy. However, the application of exogenous ATP effectively mitigated the de-creases of Fv/Fm, Fv′/Fm′, Y(Ⅱ), qP and ETR and mitigated the increases of qN and NPQ under NaCl stress. These results suggest that exogenous ATP can improve the photochemical efficiency of photo-systemⅡwhen plants were subjec-ted to NaCl stress.