中文摘要：

通过温室盆栽试验，以两种蔬菜（小白菜和苋菜）和一种昆虫（斜纹夜蛾）幼虫为对象，研究了重金属镉（Ca）在土壤-蔬菜-昆虫食物链的传递特征以及两种蔬菜中Cd化学形态分布特征．结果表明：随着土壤Cd处理浓度的升高，两种蔬菜生物量均显著下降（P〈0．05），而其各器官中的cd含量均显著上升（P〈0．05），两种蔬菜各器官Cd含量大小顺序为苋菜茎〉根〉叶，小白菜茎〉叶〉根；食用小白菜和苋菜的斜纹夜蛾幼虫体内cd含量随着土壤Cd处理含量的升高而升高，最高分别为36．7和46．3mg·kg-1，但粪便中cd含量分别高达190．0和229．8mg·kg-1，表明斜纹夜蛾幼虫食入的Cd大部分通过粪便排泄出体外．小白菜和苋菜各器官Cd化学形态均以氯化钠提取态为主（〉70％），其次为无机态和有机水溶态Cd（乙醇提取态和去离子水提取态），而不溶性Cd磷酸盐（醋酸提取态）、草酸盐结合态Cd（盐酸提取态）和残渣态均极低，这有利于重金属Cd在食物链中传递．斜纹夜蛾幼虫通过粪便排泄大量Cd以缓解Cd对自身的毒害，可有效限制Cd向下一营养级传递．小白菜和苋菜对Cd的富集性均较高，不宜在Cd高污染土壤种植．

英文摘要：

Taking two kinds of v insect species （Prodenia litura） as test materials, a study the transfer characteristics of cadmium （Cd） in rapa and Amaranthus maugostanus ） and one greenhouse pot experiment was conducted to soil-vegetable-insect food chain and the distil- bution patters of different Cd chemical forms in the organs of the two vegetables. With the increas- ing concentration of applied Cd in soil, the biomass of the two vegetables decreased significantly, while the Cd concentration in the vegetables had a significant increase. The Cd concentration in the vegetable organs decreased in the order of stem 〉 root 〉 leaf for A. mangostanus, and of stem 〉 leaf 〉 root for B. rapa. The Cd concentration in P. litura larvae also increased with the increasing concentration of Cd in soil, and the maximum Cd concentration in the P. litura larvae on B. rapa and A. mangostanus was 36.7 and 46.3 mg . kg-1 , respectively. In the feces of the larvae on B. rapa and A. mangostanus, the Cd concentration was up to 190 and 229.8 mg ~ kg-1 , respectively, suggesting that the most part of Cd absorbed by P. litura larvae was excreted out of their bodies via feces. In the organs of the two vegetables, NaCl-extractable Cd was the dominant Cd form （〉70%）, followed by d-H20- and ethanol-extractable Cd, while the HAc-extractable Cd （insolu- ble cadmium phosphate）, HCl-extractable Cd （insoluble cadmium oxalate）, and residual Cd only had a very low concentration. Such a present pattern of different Cd forms in vegetable organs could be conducive to the Cd transfer in the food chain. P. litura could ease Cd poison by excreting large amount of absorbed Cd via feces, and effectively restrict the transfer of Cd to next trophic level. Since B. rapa and A. mangostanus could accumulate large amount of Cd in their biomass, the twovegetables were suggested not to be planted in highly Cd-contaminated soil.