镉胁迫下外源钙对白菜氧化应激和NO含量的影响  

Effects of Exogenous Calcium on Oxidative Responses and Nitric Oxide in Chinese Cabbage (Brassuca pekinensis) Under Cadmium Stress

作　　者：林啸[1] 高素萍[2] 雷霆[1] 王成聪[1] 张开会[1] 

机构地区：[1]四川农业大学风景园林学院,成都611130 [2]四川农业大学园林研究所,成都611130

出　　处：《农业环境科学学报》2014年第9期1699-1705,共7页Journal of Agro-Environment Science

基　　金：四川省科技计划项目(2012FZ0083)

摘　　要：为了解镉胁迫下外源钙对白菜生理响应的调控机制,通过水培实验研究了在Cd(100μmol·L-1)胁迫下Ca(5 mmol·L-1)对白菜(Brassica pekinensis)叶片钙离子和镉离子含量、ROS和MDA含量、抗氧化酶活性、还原性谷胱甘肽和内源NO含量变化的影响,并使用0.2 mmol·L-1的三氟拉嗪(TFP)研究了Ca2+-CaM信号在其中的转导功能。结果表明:(1)Cd胁迫降低了白菜叶片的Ca含量,而外源Ca增加了Ca含量并降低Cd含量,但TFP对叶片Ca、Cd含量无明显影响;(2)Cd诱导白菜叶片ROS爆发,引起质膜过氧化,并抑制了SOD活性,提高了APX、CAT和POD活性及GSH含量,增加了叶片过氧化压力,施加外源钙后降低了这种压力,而TFP的加入却降低了这种缓解作用;(3)Cd抑制了叶片NO含量,补充外源钙后提高了NO含量,而TFP降低了外源钙对NO的上调。研究可知,外源钙能降低白菜叶片Cd含量,增强Ca含量,并通过Ca2+-CaM信号途径调节抗氧化酶和GSH含量,维持叶片ROS平衡,提高叶片内源NO的表达,从而增强白菜Cd的耐性。Calcium can alleviate heavy metal stresses in plants. A hydroponic experiment was conducted to investigate the physiological mechanisms of Chinese cabbage（Brassuca pekinensis）responses to cadmium（Cd）stress under exogenous calcium（Ca）. Concentrations of Ca and Cd ions, reactive oxygen species（ROS）, malondialdehyde（MDA）, glutathione, and endogenous nitric oxide（NO）as well as antioxidant enzymatic activities in cabbage leaves were determined. Meanwhile, the transduction function of Ca^2＋-CaM influenced by Trifluoperazine（TFP, 0.2 mmol·L^-1）was also investigated. Cadmium stress decreased Ca concentrations in cabbage leaves, while exogenous Ca addition increased Ca but decreased Cd concentrations in the leaves. However, TFP had no significant effects on the concentrations of Ca and Cd. Cadmium induced ROS outburst in cabbage leaves, resulting in the peroxidation of plasmalemma and also suppressed superoxide dismutase（SOD）activity. However Cd increased the activities of ascorbate peroxidase（APX）, catalase（CAT）, and peroxidase（POD）and the concentration of clutathione（GSH）, causing an escalated peroxide pressure in cabbage leaves. Exogenous Ca addition alleviated Cd induced pressure, but such alleviating effect was weakened by TFP addition. Nitric oxide concentrations in cabbage leaves were reduced by Cd but increased by exogenous Ca. This boosting effect of Ca was depressed by TFP addition. These results suggest that exogenous Ca reduces the Cd stress in cabbage leaves through decreasing Cd uptake and increasing antioxidant capability by Ca^2＋-CaM signal pathway.

关 键 词：镉胁迫 钙调素 抗氧化酶 活性氧 一氧化氮 

分 类 号：X171.5[环境科学与工程—环境科学]