砷诱导蚕豆气孔保卫细胞死亡的毒性效应  

Arsenic induces guard cell death in leaf epidermis of Vicia faba

作　　者：薛美昭[1] 仪慧兰[1] 

机构地区：[1]山西大学生命科学学院,太原030006

出　　处：《生态学报》2014年第5期1134-1139,共6页Acta Ecologica Sinica

基　　金：国家自然科学基金项目(30870454;30470318);教育部高等学校博士学科点基金项目(20070108007;20121401110007);山西省回国留学人员科研资助项目(2012013)

摘　　要：采用蚕豆(Vicia faba L.)叶面气孔保卫细胞,研究砷对细胞的毒性效应。结果表明,0.3—10 mg/L的NaAsO_2能降低保卫细胞活性,使部分细胞死亡,死亡率随砷浓度升高而增高。死细胞中呈现核固缩、核崩解等典型程序性死亡特征,且泛caspase抑制剂Z-Asp-CH_2-DCB能阻止NaAsO_2诱发的细胞死亡。过氧化氢清除剂过氧化氢酶与NaAsO_2共同作用时,细胞死亡率显著低于砷单独处理组,保卫细胞内Ca^(2+)水平降低,具程序性死亡特征的细胞数减少;Ca^(2+)特异性螯合剂EGTA亦能降低NaAsO_2诱发的细胞死亡。研究结果表明,NaAsO_2能诱发蚕豆保卫细胞程序性死亡,该过程由胁迫引发的ROS升高引起,ROS可能通过激活质膜Ca^(2+)通道,使胞外Ca^(2+)内流,造成胞内Ca^(2+)浓度升高,进而诱导细胞程序性死亡。Arsenic is a highly toxic metalloid for all forms of life including plants. Arsenic enters phosphate transporters as a phosphate analogue or through aquaglycoporins. Uptake of arsenic in plant in plants through tissues can affect plant metabolism, causing various physiological disorders, structural abnormalities and even plant death. Oxidative stress is considered to be a key mechanism of arsenic toxicity. In this study, the effect of sodium arsenite （ NaAsO2） on guard cell viability was investigated in detached epidermis of V. faba leaves. Epidermal strips were obtained from 4-week-old plants by peeling off the lower epidermis of V. faba leaves and incubated in 2-（N-morpholino） ethanesulfonic acid （MES） buffer containing some chemicals （ NaAsO2 with or without some antagonists） for 3 h in white light at 23 ~C as the treatments. After treatment, the epidermal strips were stained with fluorescein diacetate （FDA） to show cell viability, or with 2＇,7＇-dichlorofluoreseein diacetate （DCFH-DA） and fluo-3 acetomethoxyester （Fluo-3AM） respectively to indicate intraeellular reactive oxygen species （ROS） and calcium ion （ Ca^2＋ ） levels.

关 键 词：蚕豆保卫细胞 NaAsO2 程序性细胞死亡 ROS CA^2+ 

分 类 号：Q942.5[生物学—植物学]