Cd、As、Pb在沉水植物中的富集对其Ca吸收的影响

The Influences of Cd,As,Pb Enrichment by Submerged Plant on Its Ca Uptake

沉水植物作为水生态系统中重要的初级生产者,对水环境中的重金属元素有着较强的富集作用。钙(Ca)是植物必需的营养元素,具有极其重要的生理功能,分析沉水植物所富集的重金属元素与Ca之间的交互作用,对正确认识、利用沉水植物治理水体重金属污染有着重要的意义。湘江是中国重金属污染最严重的河流之一,其中又以镉(Cd)、砷(As)、铅(Pb)污染的问题最为突出。以湘江流域中3种典型的沉水植物(黑藻Hydrilla verticillata、苦草Vallisneria natans和菹草Potamogeton crispus)为研究对象,分析了植物体内Ca、Cd、As、Pb之间的交互作用。聚类分析、相关分析和主成分分析结果表明:黑藻和苦草中Cd、As、Pb之间的相关系数大于0.95,菹草中Cd、As、Pb元素之间的相关系数大于0.24,3种沉水植物中Cd、As、Pb之间均为正相关,但都与Ca呈负相关。Cd、As、Pb之间相关性较强,可以归为一类,具有相同的来源;而Ca可以归为另一类,这可能是因为沉水植物对Cd、As、Pb的吸收转运机制与Ca存在较大的差异,Cd、As、Pb在植物体中的富集会影响沉水植物对Ca的吸收,从而可能对其正常的生理活动产生影响。因此,在利用沉水植物监测和治理水体重金属污染时,应深入研究植物所吸收各元素之间的相互影响。

As a primary producer,submerged plants play a key role in the geo-biological-chemical circulation of pollution elements.Calcium(Ca)is one of necessary nutrients for plants and has an important physiological function.Analysis of the interactions amongthe elements accumulation by submerged plants is important for the phytoremediation of water pollution.Xiangjiang River has beenone of the most severely polluted rivers by heavy metals especially Cd,As,Pb in China.To ensure the successful application ofphytoremediation technology,the interactions among Ca,Cd,As,Pb elements accumulation by three typical species of submergedplants(Hydrilla verticillata,Vallisneria natans and Potamogeton crispus)in the Xiangjiang River were investigated.Results ofcluster analysis,correlation analysis and principal component analysis showed that Ca,Cd,As,Pb in the submerged plant can beclassified into two groups:Group one including Cd,As and Pb,the correlation coefficients between them in H.verticillata and V.natans are above0.95and0.24,but the correlation coefficients between Ca and Cd,As,Pb is negative.It may be due to the uptake ofCa by submerged plant is different from Cd,As and Pb.This indicated that the uptake of Ca would be affected by the Cd,As and Pbaccumulation in the plant,which is harmful for the growth of submerged plant.Therefore,the interactions among elementsaccumulation by submerged plant should been further investigated for the phytoremediation of water pollution.