桑-蚕系统中镉的吸收、累积与迁移

对桑－蚕系统中镉的吸收，累积与迁移行为研究结果表明：（１）桑树对土壤镉污染有一定的耐性，桑树镉累积量和相对累积率与土壤镉浓度的关系可分别用回归方程Ｔａ＝ａ＋ｂｌｏｇ（Ｓｃ）和ｌｏｇ（Ｒａ）＝ａ＋ｂｌｏｇ（Ｓｃ）描述。（２）随着土壤镉浓度的增加，镉在桑树根部的分布率明显增加，地上部分的分布率有所降低，运转到叶片的比率明显降低。（３）蚕体，蚕砂和蚕茧的镉含量，镉累积量，随着桑叶镉含量的增加而增加。

The absorption,accumulation and migration of cadmium in the system of soil mulberry and silkworm

The absorption,accumulation and migrition of cadmium(Cd) in the system of growing mulberry and feeding silkworm was conducted.The results are the following:(1)Mulberry is a kind of Cd tolerant cash crop and can absorb Cd from soil.The relationships between amount of Cd accumulation( Ta ),relative rate of Cd accumulation( Ra )in mulberry tree and Cd concentration in soil( Sc ) are expressed by the equations: Ta=a b log Sc and log Ra=a b log Sc .(2)With increasing Cd concentration in soil,distribution percentage of Cd in roots increased significantly,that in aboveground parts of mulberry decrease a little,and that in leaf decreased significantly.(3)With increasing Cd content in the mulberry leaf,Cd content in silkworm body,excrement,chrysalis and silk shell also increased.(4)In the subsystem of growing mulberry,about 50% of amount of Cd accumulation in the mulberry tree was removed from soil by using leaf for feeding silkworm and cutting branch.In the subsystem of feeding silkworm,4.7% of amount of Cd accumulation in taked mulberry leaf by silkworm was removed from feeding silkworm subsystem to reeling mill with cocoon.Therefor for the system of growing mulberry and feeding silkworm,only 0.77% of amount of Cd absorbed by mulberry tree were removed from the system.(5)It should pay serious attention to manage the Cd cotaining residus produced by feeding silkworm,when Cd polluted land was utilized for growing mulberry.