滨海盐渍土壤中不同类型盐生植物富集镉的效应

摘要

为了利用被镉污染的滨海盐渍土壤,通过实验对比分析3种不同类型盐生植物对盐渍土中镉的富集效应,以期初步探明不同类型盐生植物在镉污染盐渍土壤修复中的效果.选择的3种盐生植物类型是:聚盐盐生植物,泌盐盐生植物和避盐盐生植物.通过温室盆栽实验,将植物在不同镉含量的盐渍土壤中种植培养60 d,测定和分析不同类型盐生植物对镉的生物浓缩因子、转移系数以及植株内地上部分和根部生物量和镉含量的变化.结果表明,不同镉含量的土壤对碱蓬和芦苇的生长影响较小,对二色补血草的生长影响较大.不同镉含量的土壤中,芦苇地上部分镉的生物浓缩因子变化差异不显著,并且其地上部分吸收镉的百分率较高.碱蓬和芦苇的转移系数大于二色补血草的转移系数,并且碱蓬的转移系数在不同镉含量的土壤中变化不显著;二色补血草的转移系数随着土壤中镉含量的增加而显著增大.3种盐生植物中,碱蓬最具修复镉污染盐渍土壤的潜力,这可能和它是聚盐盐生植物的生理类型有关.芦苇整个植株的地上部分富集镉的总量在3种植物中是最高的,因此,芦苇在镉含量较低时也可以做为镉污染盐渍土壤的修复材料.%In order to utilize saline soil polluted with Cd in the coastal region,the experiment was conducted to analyze the differences in accumulation of Cd by three types of halophytes and to determine the effectiveness of the different halophytes in the remediation of saline soils polluted with Cd.The study was conducted using pot experiments in a greenhouse,and salt accumulating,salt secreting,and salt avoiding plants were used as the study subjects.The halophytes were planted with supplies of salt and Cd,and the bioconcentration factor,translocation factor,biomass,and Cd content of the above ground parts and the root were investigated after 60 days of culture.The results indicated that different Cd contents in the soil had little effect on the growth of Suaeda glauca and Phragmites australis,but had a greater influence on the growth of Limonium bicolor.The variation of the Cd concentration factor in the aboveground parts of Phragmites australis was not significant,and the percentage of Cd uptake in the aboveground part was higher.The translocation factor in S.glauca and P.australis was greater than that in L.bicolor;the translocation factor in S.glauca did not change significantly with the change in Cd contents in the soil,but it increased greatly in L.bicolor.Among the three types of halophytes,S.glauca had the highest potential to remediate coastal saline soil polluted with Cd,which may be related to the physiological type of this halophyte as salt accumulating plant.Among the three types of halophytes,P.australis accumulated the highest total amount of Cd in the aboveground parts.Therefore,P.australis can be used to remediate soils that have lower Cd levels.