LAS和Cd复合污染对小白菜生长及保护酶系统的影响

Effect of LAS-Cd compound pollution on the growth and protective enzyme system of Brassica campestris ssp. chinensis

【目的】揭示LAS和Cd复合污染对小白菜的伤害机理，为小白菜食用安全性评估提供参考。【方法】采用盆栽试验，研究了不同质量浓度LAS（0．0，0．5，5．0，50．0mg／kg）和Cd（0．0，1．0，10．0，20．0mg／kg）及其复合污染对小白菜生长及保护酶系统的影响，其中以不添加LAS和Cd为对照组。【结果】除5．0mg／kgLAS＋1．0mg／kgCd处理组外，5．0～50．0mg／kgLAS＋1．0～20．0mg／kgCd处理组的叶绿素（Chl）含量和叶绿素a与b含量的比例（Chla／Chlb）与对照组差异均不显著（P〉0.05）。5．0～50．0mg／kgLAS＋1．0～20．0mg／kgCd复合处理组的小白菜生物量大于相应浓度的Cd单一处理组，叶片中的硝酸还原酶（NR）、超氧化物岐化酶（SOD）、抗坏血酸过氧化物酶（APX）活性均高于对照组，丙二醛（MDA）含量则略低于对照组或与对照组接近。【结论】质量浓度为5．0～50．omg／kg的LAS可以缓解1．0～20．0mg／kgCd对小白菜的伤害。

[Obejective] The experiment was conducted in order to study the rules of low level Linear alkylbenzene sulphonates （LAS） and Cadmium（Cd） compound on the physiological and biochemical characteristics of the Brassica campestris ssp. chinensis. Those can provide reference of the vegetable for human consumption in the risk assessment. [Method] The pot experiments were carried out with Brassica campestris ssp. chinensis as material to study the effect of applying different levels of LAS （0.0,0.5,5.0, 50.0 mg/kg） and Cd （0.0,1.0,10.0,20.0 mg/kg） compound in the soil,and these pots were placed in a greenhouse. [Result] Compared with the Cd separateness（1.0--20.0 mg/kg）,the 5.0--50 mg/kg LAS＋ 1.0--20.0 mg/kg Cd combined treatment enhanced the biomass and improved the activities of Nitrate reductase（NR） ,Superoxide dismutase（SOD）, Ascorbate peroxidase （APX） in the leaf of Brassica campestris ssp. Chinensis. On the contrary,the content of Malondialdehyde（MDA） was lower than or close to that of Cd separateness. Total chlorophyll （Chl） content and the ratio of chlorophyll a to chlorophyll b （Chla/ Chlb） in the leaves were not significant at P=0.05 level except 5.0 mg/kg LAS＋1. 0 mg/kg Cd treatment group. [Conclusion] 5.0--50 mg/kg LAS could alleviate the nocuity of the 1.0--20.0 mg/kg Cd separateness on the Brassica campestris ssp. chinensis.