中文摘要：

植物叶表面的气孔保卫细胞是研究信号转导的模式实验系统,对环境变化反应灵敏而准确,采用蚕豆叶面气孔保卫细胞,研究了铝（AlCl3）对细胞的毒性效应。结果表明,在1～10 mmol.L^-1范围内,AlCl3可使气孔保卫细胞活性降低,部分细胞死亡,且随着浓度的增高细胞死亡率增高;死细胞呈现核固缩、核降解、凋亡小体等典型凋亡特征。凋亡抑制剂Z-Asp-CH2-DCB或TLCK与AlCl3共同作用时,保卫细胞死亡率显著降低;一定浓度的抗坏血酸（AsA）或过氧化氢酶（CAT）以及Ca2＋螯合剂乙二醇四乙酸酯（EGTA）或Ca2＋通道抑制剂LaCl3与AlCl3共同作用时,细胞死亡率降低。研究结果表明,铝诱导的蚕豆保卫细胞死亡可能是一种细胞凋亡过程,由胁迫诱发的活性氧介导,通过激活质膜钙通道,引起胞内Ca2＋水平改变,进而介导细胞凋亡。

英文摘要：

Aluminum（Al）is the most abundant metallic element in the earth′s crust.Virtually all food,water,air,and soil contain some alu-minum.Since the toxic effect of Al on plants was first discovered in 1918,it has been found that Al is a major factor reducing plant growth and crop production in acid soils.However,the mechanism of Al toxicity is still not completely clear.Stomatal guard cells in the epidermis of plant leaves respond to environment changes sensitively and accurately,commonly used as a model experimental system to study signal trans-duction.In this study,effect of aluminum on guard cell viability was investigated in Vicia faba leaves.Young fully expanded leaves from 4-week-old plants were used as materials.Epidermal strips were obtained by peeling off the lower epidermis from young fully expanded leaves.They were incubated in 2-（N-morpholino）ethanesulfonic acid（MES）buffer containing some chemicals（AlCl3 with or without some alle-viants）for 3 h at 23 ℃ in white light for the treatment.After then,the strips were stained with fluorescence reagent fluorescein diacetate（FDA）,propidium iodide（PI）,2′,7′-dichlorofluorescein diacetate（DCFH-DA）and fluo-3 acetomethoxyester（Fluo-3 AM）,respectively,and observed under a fluorescence microscope.The results of the present study showed that aluminum treatment significantly decreased cell viability and induced cell death at concentrations of 1,2.5,5 mmol.L-1 and 10 mmol.L-1.A synchronous increase in cell death rate and in-tercellular ROS and Ca2＋ levels occurred in V.faba guard cells exposure to Al.The dead cells showed typical features of apoptosis,such as nuclear condensation,fragmentation and apoptosis bodies.Z-Asp-2,6-dichlorobenzoyloxymethylketone（Z-Asp-CH2-DCB）and Nα-tosyl-Lys-chloromethyl keton（TLCK）,two types of specific caspase inhibitors,significantly blocked Al-induced cell death.The occurrence of characteristic features of apoptosis in Al treated guard cells and the blockade of Al-induced cell death by apoptosis