苎麻对镉毒害的生理耐性机制及外源精胺的缓解效应  

Endurance Mechanism of Ramie to Cd and the Alleviating Effect of Exogenous Spermine

作　　者：王欣[1] 刘云国[1] 艾比布.努扎艾提 张东梅[1] 徐卫华[1] 周鸣[1] 柴立元[1] 

机构地区：[1]湖南大学环境科学与工程学院,湖南长沙410082

出　　处：《农业环境科学学报》2007年第2期487-493,共7页Journal of Agro-Environment Science

基　　金：国家"863"高科技攻关项目(2001AA644020);湖南省自然科学基金资助项目(04JJ3013);湖南省软科学研究重点项目"湖南省生态环境保护与建设研究";国家发改委科学基金资助项目(2002BA516A15-12)

摘　　要：采用盆栽试验方法,研究了不同浓度Cd胁迫下苎麻体内的生理代谢变化。结果表明,营养生长期苎麻对Cd的忍耐阈值为80mg·kg-1左右,Cd胁迫在此浓度范围内时,苎麻叶绿素、类胡萝卜素和可溶性蛋白质含量均有不同程度的增加,且抗坏血酸-谷胱甘肽循环中四个关键指标值--还原型抗坏血酸和还原型谷胱甘肽含量、抗坏血酸过氧化物酶和谷胱甘肽还原酶活性均上升,表明苎麻通过加速该循环清除活性氧,使植株避免氧化伤害;高于此浓度的Cd胁迫使苎麻抗氧化防御体系遭到破坏,生理代谢趋于紊乱。证明苎麻最适宜的外源精胺浓度为0.5×10-4mol·L-1,喷施该浓度精胺可显著提高不同浓度Cd胁迫下苎麻叶绿素、类胡萝卜素和可溶性蛋白质的含量,有效地抑制膜脂过氧化,极大地提高了谷胱甘肽与抗坏血酸的含量,同时使谷胱甘肽还原酶和抗坏血酸过氧化物酶的活性明显增强,从而使整个抗氧化循环高效运转,这对于增强苎麻对Cd的抗性是至关重要的。The variations of physiological metabolism of ramie under different Cd concentrations were studied. 80 mg·kg^-1 Cd was the threshold of ramie during its vegetative growing period. In this range, chlorophyll, carotenoid and soluble protein were all stimulated, and four key indices involving in AsA-GSH cycle-ascorbic acid （AsA）, glutathione （GSH）, ascorbate peroxidation （APX） and glutathione reductase （GR） were all enhanced, indicating that reactive oxygen species induced by Cd could be eliminated as much as possible by this acceleratory cycle, while, the defending system of ramie was suffered with higher Cd concentration. The optimum exogenous spm concentration for ramie was 0.5×10^-4 mol.L^-1, which could promote the content of chlorophyll, carotenoid and soluble protein significantly and inhibit the cell membrane- lipid peroxidation effectively. At the same time, the content of GSH and AsA and the activity of APX and GR were also increased markedly with exogenous spm, which resulted in the whole cycle operating at higher speed that meant a lot to strengthen the resistance of ramie to Cd.

关 键 词：Cd 苎麻 精胺 叶绿素 可溶性蛋白质 丙二醛 抗坏血酸-谷胱甘肽循环 

分 类 号：Q945.78[生物学—植物学]