镉胁迫对苜蓿膜脂过氧化的影响及保护系统的应答

Effect of Cadmium Stress on Cell Membrance Lipid Peroxidation in Medicago sativa L.cv. Zhaodong and Replies of Protecting System to It.

采用盆栽实验方法,研究了不同浓度的Cd对苜蓿叶绿素含量和叶片中膜脂过氧化的影响。结果表明:与对照相比,Cd浓度0.1mg/L、1.0mg/L处理后,叶绿素a与叶绿素b含量增加,达到50mg/L时,显著下降(P<0.01);超氧物歧化酶(SOD)活性呈先升后降的趋势;愈创木酚过氧化物酶(GPOD)、过氧化氢酶(CAT)在Cd浓度为10.0mg/L、1.0mg/L时活性最高;抗坏血酸(AsA)、谷胱甘肽(GSH)的含量在Cd浓度为50mg/L时达高峰。适度镉胁迫下,苜蓿依赖于SOD、GPOD和CAT清除体内活性氧,在重度胁迫下,叶绿体内主要依赖抗坏血酸-谷胱甘肽循环系统来抵御氧自由基的毒害。

s: Effects of different concentrations of cadmium(0,0.1,1.0,10.0,50.0mg/L)on chlorophyll content and cell membrance lipid peroxidation in Medicago sativa L.cv.Zhaodong were studied. Cd below 1.0mg/L enhanced the chlorophyll content,whereas the growth was seriously inhibited by 50mg/L Cd.SOD activity first rised then droped.The activity of GPOD and CAT increased in the treatment of 10.0mg/L and 1.0mg/L,but dropped dramatically in the treament of 50mg/L. The activity of CAT was the highest in the treatment of 1.0mg/L. AsA and GSH content increased at 50 mg/L Cd. Medicago sativa L. probably depended on SOD,GPOD,CAT to eliminate ROS(reactive oxygen species) under temperate Cd stress,but might depended on Halliwell-Asada cycle to relieve damage of ROS under severer stress of Cd.