【摘要】 以草甸棕壤为供试土壤,以蚕豆幼苗根尖有丝分裂指数、染色体畸变率以及微核率,幼苗叶片内抗氧化酶活性、植物内源激素含量为指标,采用盆栽方法研究了0~10 mg.kg-1镉胁迫对植物细胞的遗传和生态毒性效应.结果表明,在此浓度范围内,蚕豆根尖细胞有丝分裂指数、染色体畸变率以及微核率均随镉浓度增加呈显著的剂量-效应正相关关系,其中微核率变化最为明显,处理组微核率分别为对照组的1.43~3.22倍;蚕豆幼苗叶片内的SOD和POD活性变化呈先升高后下降的趋势;而CAT活性随镉浓度增加其变化规律与SOD、POD相反.此外,镉胁迫下植物激素脱落酸(ABA)、赤霉素(GA3)与细胞分裂素类的玉米素和玉米素核苷总含量(Z&ZR)均表现出低浓度下诱导和较高浓度下诱导率降低的趋势,在镉浓度为2.5 mg.kg-1时3种植物激素含量均达到最高值,分别比对照组增加了6.6%、4.0%和12.6%.研究表明,各指标对污染物的毒性具有响应且响应的域值及其敏感度不同,将各指标综合使用可使土壤镉污染的遗传和生态毒性诊断更为有效.更多还原

【Abstract】 The genetic and eco-toxic effects of Cd(0-10(mg·kg^-1)) were studied with Vicia faba（broad bean） as the test species using meadow brown soil in pot experiments by means of several indexes,such as Vicia faba root tip micronucleus frequency（MCN）,mitosis index（MI）,and chromosomal aberrations frequency（CAF）,antioxidant enzymes superoxide dismutases（SOD）,peroxidases（POD）,catalase（CAT） and phytohormone abscisic acid（ABA）,gibberellic acid（GA₃） and zeatin and zeatin riboside（Z&ZR）.Results indicated the significant positive dose-response correlations were found between Cd²⁺ concentrations and the tested indexes（MI, MCN and CAF）.Among of them,MCN is the most sensitive,and the MCN frequencies were 1.43-3.22 times higher in Cd treatment soils than that of in the controls. SOD and POD in seedling leaves of broad bean were response to the Cd stress,showing a trend of increase with Cd concentrations initially and then decreased.The CAT response to Cd in soils was opposite to that of SOD and POD.In addition, there were stimulation and inhabitation effects between Cd and ABA,GA₃ and Z&ZR in lower and higher Cd concentrations.The highest contents of phytohormone（ABA,GA₃ and Z&ZR） were found when Cd was at 2.5(mg·kg^-1),which was 6.6%,4.0% and 12.6% higher than that in the control,respectively.Our study indicated that all indexes were response to the Cd stress in soils,but the sensitivity of each index was different from each other.All these indexes combined should be more efficiency in the diagnosis of geno-,and eco-toxicity of cadmium in soils.更多还原