细胞外ATP和水杨酸对烟草光合指标的影响

Effects of extracellular ATP and salicylic acid on photosynthetic index of tobacco

关键词:  细胞外ATP  水杨酸  光合速率  叶绿素荧光参数

Key words:  extracellular ATP  salicylic acid  photosynthesis rate  chlorophyll fluorescence parameter

摘要:

研究了细胞外ATP(eATP)和水杨酸(SA)对烟草(Nicotiana tabacum)叶片的气孔导度(GH₂O)、蒸腾速率(E)、光合作用速率(A)与叶绿素荧光参数[包括PSⅡ潜在最大光化学量子效率(Fv/Fm)、PSⅡ光适应下实际光化学效率Y(Ⅱ)、电子传递速率(ETR)、非光化学荧光淬灭(NPQ)和光化学荧光淬灭(qP)]的影响。结果表明:SA能导致A、GH₂O和E的下降,而eATP的处理能缓解SA造成的A、GH₂O和E的下降; 但SA未对叶绿素荧光参数Fv/Fm、Y(Ⅱ)、NPQ、qP和ETR造成显著影响,eATP的加入也未改变SA处理下叶片叶绿素荧光参数的水平。这说明SA能导致光合作用的抑制,而eATP能明显缓解SA对光合作用的抑制,但以上作用可能均和光反应阶段无关。并对其内在机理进行了探讨。

Abstract:

The present work studied the effects of extracellular ATP(eATP)and salicylic acid(SA)on transpiration rate(E),stomatal conductance(GH₂O),photosynthesis rate(A)and chlorophyll fluorescence parameters,including maximal photochemical efficiency of PSⅡ(Fv/Fm),effective photochemical quantum yield of PSⅡ(Y(Ⅱ)),PSⅡ electron transport rate(ETR),non-photochemical quenching coefficient(NPQ)and the coefficient of photochemical fluorescence(qP))of tobacco(Nicotiana tabacum). The results showed that the transpiration rate(E),stomatal conductance(GH₂O)and photosynthesis rate(A)decreased under SA stress,while these decreases were anesised by the addition of eATP. However,SA had no significant effects on the chlorophyll fluorescence parameters,and the addition of eATP did not significantly changed the values of the chlorophyll fluorescence parameters under SA stress. These results indicated that SA could inhibit photosynthesis of tobacco leaves and the addition of eATP could alleviate the inhibition of photosynthesis by SA stress,while these effects were not related to the light reaction. We also discussed the possible mechanism based on these observations.