胞质pH参与5–氨基乙酰丙酸诱导的苹果叶片气孔开放  

Cytoplasmic pH is Involved in 5-aminolevulinic Acid (ALA)-induced Stomatal Opening in Apple Leaves

作　　者：胡健 安玉艳[1] 蔡长玉 何莎莎 汪良驹[1] HU Jian;AN Yuyan;CAI Changyu;HE Shasha;WANG Liangju(College of Horticulture,Nanjing Agricultural University,Nanjing 210095,China)

机构地区：[1]南京农业大学园艺学院

出　　处：《园艺学报》2019年第10期1869-1881,共13页Acta Horticulturae Sinica

基　　金：国家自然科学基金项目(31401820,31772253)

摘　　要：为了揭示5-氨基乙酰丙酸(ALA)调控气孔运动的机制,以‘富士’苹果试管苗叶片下表皮为材料,研究了ALA调节气孔运动与胞质pH的关系,发现脱落酸(ABA)和苄胺(弱碱)可以诱导气孔关闭,并引起胞质pH和活性氧(ROS)显著上升;ALA和丁酸(弱酸)可以抑制ABA诱导的气孔关闭,同时抑制胞质pH和ROS上升。苄胺能减弱ALA对ABA诱导气孔关闭的抑制效应,而ALA和丁酸则抑制外源H2O2和Ca^2+诱导的气孔关闭。这些结果表明,胞质pH处在ALA调节气孔运动信号途径的上游参与气孔调节。qRT-PCR分析结果显示,ABA诱导苹果叶片下表皮细胞液泡膜H^+-ATPase编码基因Mdvha-c2和Mdvha-c3上调表达,而ALA则抑制这种效应,说明ALA可能通过抑制液泡膜离子泵活性,减少胞质H^+向液泡内运输,导致胞质酸化,从而促进气孔开放。因此,ALA对苹果叶片气孔运动的调节效应可能经由胞质pH途径实现。Stomata is the main channel for CO2 to enter into leaf mesophyll cells,and its aperture plays a key role in photosynthetic rate. Previous studies have shown that 5-aminolevulinic acid(ALA)is involved in stomatal regulation in apple leaves,but the underlying mechanism has not been fully elucidated. In the present work,the effects of ALA on cytoplasmic pH and stomatal movement were studied with the abaxial epidermis of leaves of Fuji apple(Malus × domenstica Borkh). Results showed that when stomatal closure was induced by ABA and benzylamine,the fluorescence intensity of cytoplasmic pH and reactive oxygen species(ROS)increased significantly. When ALA and butyrate were used to inhibit ABA-induced stomatal closure,they also inhibited ABA-induced increase of cytoplasmic pH and ROS fluorescence intensity. Benzylamine weakened the effect of ALA on the stomatal closure induced by ABA,while ALA and butyrate inhibited stomatal closure induced by exogenous H2O2 and Ca2+. These results suggest that cytoplasmic pH is involved in stomatal regulation at the upstream of the signal pathway of ALA regulating stomatal movement. Analysis of qRT-PCR showed that ABA induced up-expressions of Mdvha-c2 and Mdvha-c3 which encode subunits of tonoplast H+-ATPase,whereas ALA inhibited this effect. These suggest that cytosolic acidification induced by ALA may be related to the decrease of ion pump activity in the vacuolar membrane. Based on the above results,the authors conclude that the effect of ALA on stomatal movement in apple leaves is mediated by cytoplasmic pH pathway.

关 键 词：苹果 ABA ALA CA^2+ 胞质pH H2O2 气孔运动 

分 类 号：S661.1[农业科学—果树学]