水体铯污染的生物效应与修复植物筛选

Biological effects of cesium contamination and screening of plants for phytoremediation of cesium contaminated water

研究铯对水生植物的生物效应,筛选对铯富集能力强的水生植物,能够为水体铯污染的修复治理提供方法依据。设计铯污染浓度为0、0.5、2.5和10 mg/L,9种水生植物,3次重复,研究铯对不同水生植物生物效应(BE)和不同水生植物对铯的吸收和富集情况。结果表明,不同植物对水体铯污染有不同的反应。就增加鲜重而言,绿萍、水花生、轮叶狐狸藻、水蓼、水葱增加鲜重大于对照;眼子菜、水葫芦、水稻增加鲜重小于对照;不同植物的铯含量不同。平均铯含量依次为水花生>水蓼>水稻>水葫芦>水葱>眼子菜>轮叶狐狸藻>绿萍,其中水花生为935.12 mg/kg DW,水蓼为825.93 mg/kg DW,水稻为723.38 mg/kg DW;不同植物清除水体铯污染的能力不同。收获时水体铯浓度降低最多至最少的依次是水蓼、水花生、水稻、轮叶狐狸藻、水葱、水葫芦、绿萍和眼子菜。根据生物效应、植物铯含量、水体铯减少情况,水花生、水蓼、水葫芦和水稻可以作为铯污染水体修复植物。

With the purpose of screening of cesium hyperaccumulators and exploring new methods to remove cesium from contaminated water,nine kinds of aquatic plants( Alternanthera philoxeroides,Polygonum hydropiper,Oryza. sativa L.,Eichhornia crassipes,Scirpus tabernaemontani,Potamogeton pectinatus L.,Myriactis wallichii Less. and Azolla imbricata( Roxb.) Nakai) were respectively treated with nutrient solution containing 0( CK),0. 5,2. 5,10 mg·L- 1cesium,and the biological effects and the uptake and distribution of cesium in these plants were investigated. The results showed that the responses of different plants on cesium contamination were significantly different; compared with CK,fresh weight of Azolla imbricata( Roxb.) Nakai,Alternanthera philoxeroides,Myriactis wallichii Less,Polygonum hydropiper and Scirpus tabernaemontani Gmel,increased under cesium contaminated water,but fresh weight of Potamogeton pectinatus L.,Eichhornia crassipes and Oryza. sativa L. decreased; under the same cesium treatment concentration,the cesium accumulation of plants were obviously different in different kinds of plants,and from highest to lowest were: Alternanthera philoxeroides( 935. 12 mg / kg DW),Polygonum hydropiper( 825. 93 mg / kg DW),Oryza. sativa L.( 723. 38 mg / kg DW),Eichhornia crassipes,Scirpus tabernaemontani,Potamogeton pectinatus L.,Myriactis wallichii Less. and Azolla imbricata( Roxb.) Nakai); different kinds of plants had obvious differences in removing cesium from the contaminated water. By the harvest time,the extent of reduction of cesium concentration in contaminated water in the order from big to small were: Polygonum hydropiper,Alternanthera philoxeroides,Oryza. sativa L.,Myriactis wallichii Less.,Scirpus tabernaemontani,Eichhornia crassipes,Azolla imbricata( Roxb.) Nakai,and Potamogeton pectinatus L. According to the biological effects,the cesium accumulation in different kinds of plants and the capacity of plants to remove cesium in contaminated water,we suggested that Alternanthera philoxeroides,Polygonum hydropiper,Eichhornia crassipes and Oryza. sativa L. might be the promising plants for phytoremediation of cesium contaminated water.