田间条件下小白菜对外源Cd的动态吸收特征

目的]探究田间条件下小白菜对外源Cd的动态吸收特征,为Cd污染土壤上蔬菜安全生产提供理论依据。方法]采用田间微区试验,共设4个Cd浓度处理,即0(CK)、1、2、5 mg/kg,每处理3次重复,研究外源Cd对小白菜生长的影响及小白菜对外源Cd的动态吸收特征。结果]随着外源Cd浓度的升高及生长时期的延长,Cd对小白菜生长的抑制加重。5 mg/kg处理55 d时,小白菜的根长、株高、生物量较CK下降幅度均达到最大。任一Cd浓度下小白菜的Cd含量在前45 d快速增加,45 d后增速放缓,地下部Cd含量在55 d达到最大值,地下部平均Cd含量是地上部的1.62倍。结论]Cd对小白菜的生长作用受Cd污染浓度、生长时期双重影响,且不同外源Cd浓度下小白菜各部位对Cd的吸收在不同生长时期呈现动态差异。

Study on the Dynamic Accumulation of Exogenous Cadmium in Brassica chinensis L.under Field Conditions

Objective]To investigate the dynamic absorption characteristics of Brassica chinensis L.under field conditions,and to provide the theoretical basis for the safe production of vegetables on Cd contaminated soil.Method]Set 4 Cd concentration treatments,namely,0(CK),1,2,5 mg/kg,each treatment for 3 times.The Cd effects on the growth of Brassica chinensis L.and the dynamic accumulation of exogenous Cd in Brassica chinensis L.was studied by field micro-plot experiments.Result]The results showed that with the increase of exogenous Cd concentration and the extension of growth period,Cd inhibited the growth of Brassica chinensis L..The root length,plant height and biomass of Brassica chinensis L.reached the maximum value at 55 d under treatment of 5 mg/kg.The Cd content in Brassica chinensis L.increased rapidly at the first 45th days,while the rising tendency slowed down after the 45th days.However,the root was 1.62 times the Cd absorption of aboveground parts signally.Conclusion]The Cd effects on the growth of Brassica chinensis L.were affected by the different concentrations of Cd and the growth stages of Brassica chinensis L.,also the accumulation of Cd in different parts of Brassica chinensis L.appeared dynamic discrepancy on account of different growth stages under varied concentrations of Cd.