外源钙对镉胁迫下芥菜型油菜幼苗生长和生理特性的影响

通过水培试验研究5、10mmol·L^-1Ca^2＋对不同水平镉处理下的油菜幼苗生物量、根长、丙二醛（MDA）和H2O2含量以及抗氧化酶活性的影响,利用HPLC分析外源钙对油菜幼苗镉胁迫下还原型谷胱甘肽（GSH）含量的变化情况。结果表明,镉处理浓度为150、300、450μmol·L-^1时,5和10mmol·L-1Ca^2＋均能有效增加植株的生物量和根长,5mmol·L^-1Ca^2＋能显著减少油菜幼苗中MDA和过氧化氢（H2O2）含量,增强超氧化物歧化酶（SOD）、过氧化氢酶（CAT）、谷胱甘肽还原酶（GR）、谷胱甘肽过氧化物酶（GPX）和谷胱甘肽转移酶（GST）的活性及GSH的含量。镉胁迫浓度为600μmol·L-1时,施钙后油菜幼苗出现生物量低、MDA含量高、抗氧化酶活性和GSH含量均下降,与CK相比差异不显著（P〉0.05）。镉处理浓度≤450μmol·L-1时,5mmol·L^-1Ca^2＋能明显缓解芥菜型油菜生长和生理所受胁迫,外源钙可作为减轻镉胁迫对油菜毒害的保护剂。

Effect of Exogenous Calcium on Seedling Growth and Physiological Characteristics of Brassica juncea Under Cadmium Stress

The purpose of this study was to investigate the effects of exogenous calcium on seedling growth and physiological characterfstics of Brassicajuncea under cadmium stress. Calcium of 5 mmol·L^-1 and 10 mmol· L^-1 was used to regulate the growth of seedling of Brassicajuncea under the stress of cadmium of 150, 300, 450 and 600 μmol· L^-1 by water cultivation. The changes of the activities of antioxidative enzymes and the content of malondialdehyde （MDA）were determined. The method for determination of reductive glutathione （GSH）was based on high per- formance liquid chromatography（HPLC ）. Biomass and root length of Brassicajuncea were significantly increased under the treatment of 5 and 10 mol· L^-1 calcium. Under the circumstance of 5 mmol· L^-1 calcium, contents of MDA and H2O2 were decreased effectively, the activities of superoxide dismutase （ SOD ）, catalase （ CAT ）, glutathione reductase （ GR ）, glutathione peroxidase （GPX）, glutathione S-transferase （GST） and the content of GSH were enhanced under 150, 300 and 450 μmol· L^-1 cadmium stress. There were no significant differences between treatment of within calcium and control（without calcium ） under the circumstance of 600μ mol· L^-1 cadmium, the content of MDA was increased while the biomass, the activities of antioxidative enzymes and the content of GSH were descended. 5 mmol· L^-1 calcium could allevi- ate the stress of 450 μmol· L^-1 cadmium and effectively promote the physiological activities of antioxidative enzymes in Brassicajuncea, as a protective agent for growth of seedling of Brassicajuncea under the stress of cadmium.