VA菌根降低植物对重金属镉的吸收

高等植物在漫长的进化过程中对环境产生种种适应机制。菌根的形成即是对自然土壤中有效磷不足的一种适应。菌根真菌与寄主根系共生形成菌根后,真菌的菌丝可以远远伸出根际范围从而扩大了植物对土壤中难以移动的磷元素的吸收范围而改善植物的磷素营养。因此,地球上90％的陆生植物都可形成菌根。菌根的形成,不仅促进了植物对磷的吸收,而且也影响到植物对其它元素包括重金属的吸收。在重金属污染的土壤中,菌根对植物重金属的吸收将影响到植物对重金属的抗性和农产品品质。本文拟研究在添加镉的土壤上菌根对植物吸收Cd的影响。

Vesicular-arbuscular mycorrhizae decrease cadmium uptake by plant

In a pot experiment, vesicular-arbuscular mycorrhizal fungi (VAMF) (Glomus mosseae) along with various amounts of phosphorus and lime were introduced to an infertile acidic red earth (Typic hapludalf) previously amended with 8 mg Cd/kg soil. Dry matter of maize shoot after 60 days growth was collected and Cd as well as P content were determined. Its was found that inoculation of VAMF significantly increased root infection and the highest infection occurred with lower P, lime treatment suggesting VAMF infection was influenced by high P and acidic reaction of the soil. Shoot Cd content indicated that the highest VAMF infection significantly decreased Co accumulation in plant shoot. However, Cd accumulation in shoot was relatively unaffected by VAMF in other lower infection treatments. It is suggested from the results that heavy mycorrhizal infection may contribute to restricting Cd uptake by host plants.