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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。
A pot experiment was conducted to study the effects of different concentrations of Cd on chlorophyll content and lipid peroxidation in leaves of Medicago sativa. The results showed that the contents of chlorophyll a and chlorophyll b increased when Cd concentration was 0.1 mg / L and 1.0 mg / L, and decreased significantly when the concentration was 50 mg / L (P <0.01). Compared with the control, the content of superoxide dismutase SOD activity increased first and then decreased; the activity of guaiacolperoxidase (GPOD) and catalase (CAT) was the highest when Cd concentration was 10.0mg / L, 1.0mg / L; AsA ), Glutathione (GSH) reached the peak when Cd concentration was 50mg / L. Under moderate Cd stress, alfalfa relied on SOD, GPOD and CAT to remove reactive oxygen species (ROS). Under severe stress, chloroplast mainly relied on ascorbate-glutathione circulatory system to resist the poisoning of oxygen free radicals.