栽培植物的耐镉性与镉污染土壤的农业利用

为了有效实施镉污染农田农业生态整治与安全高效利用策略 ,采用室外微区池栽培实验 ,对我国南方几种主要栽培植物耐土壤Cd污染能力进行了比较分析。指出禾谷类作物水稻和玉米虽然对Cd的生理耐受性较强 ,但其产品 (籽实 )易因Cd污染影响而丧失食用价值 ,属于污染敏感型作物 ,不宜在污染区种植 ;油菜、花生和甘蔗等对Cd的生理耐性较强 ,产品 (种子油、蔗糖 )中Cd存留量低 ,对食用品质影响较小 ,可考虑在轻污染区保留种植 ,但油料作物的秸秆和饼粕、蔗渣等应作为污染物妥善处理 ,不宜作肥料或饲料利用 ;纤维植物棉花、红麻、苎麻和蚕桑对土壤Cd污染都有不同程度的耐受性 ,产品质量基本不受Cd污染的影响 ,产品中的Cd不进入食物链 ,因此 ,在对污染农田实施农业生态整治与安全高效利用策略时 ,可作为改种改制的首选作物。

Tolerance of Cultivated Plants Towards Cadmium and Utilization of Cd-Polluted Soils in Agriculture

A comparative evaluation of tolerance of several main cultivated plants towards cadmium in south China was conducted for making strategy of agro-ecological regulation and safe-and-efficient utilization in farmland polluted by Cd. It revealed that cereals such as Oryza sativa and Zea mays had a strong resistance to Cd toxicity physiologically, whereas, their kernels (grains) were easily to be polluted and hence lost their eatable value. On the other hand, other plants such as Brassica napus, Arachis hypogaea and Saccharum officinarum etc. also had a strong resistance to Cd pollution physiologically. Meanwhile, Cd stocks in their products (oil or sugar) are very small and had little effects on their eatable quality,making it possible to cultivate these crops in some slightly Cd polluted farmlands. But the straw and dregs of oil crops, and sugarcane bagasse should be properly treated as pollutants, as they were suitable neither as manure nor stock food. Fibre crops, such as Gossypium hirsutum, Hibiscus cannabinus, Boehmeria nivea and Morus alba were resistant to soil Cd-pollution at different degrees. There were basically no unfavorable effects of soil Cd pollution on the products of fibre crops. Moreover, there was hardly any Cd coming into the food chain through these crops. Therefore, in considering of the strategy of agro-ecological regulation and safe-and-efficient utilization of Cd-polluted farmlands, these fibre crops should firstly replace those sensitive crops in the polluted region.