鱼腥草对土壤中镉的富集及根系微生物的促进作用

通过采集自然条件的鱼腥草和未受污染的土壤,在实验室条件下培育,以及利用镉的筛选,培养出土壤菌悬液,研究了鱼腥草Huttuynia cordata对土壤中镉的富集作用,以及经过根系微生物处理后放线菌对富集后转移的促进作用。结果表明,根部经过微生物处理的鱼腥草地上部（土壤含镉200 mg·kg^-1）有最高的含镉浓度和最大的富集量,分别是是对照组的20倍和50倍。土壤含镉50 mg·kg^-1时,鱼腥草地上部与地下部镉富集量的比例是2.5,高于对照组（1.5）。而当土壤含镉200 mg.kg^-1时,经过处理的鱼腥草地上部与地下部镉含量之比是未经处理的2倍。所以,鱼腥草对土壤中的镉有很强的富集作用,且在根系微生物的促进下,地下部的镉能更有效地转移到地上部,大大加强植物的修复效率;且与其他的诸如添加化学螯合剂等方法相比,土壤根系微生物能更好地适应植物根系环境,更不会对土壤本身的微生态系统造成二次污染。所以研究根系环境中微生物、根系、土壤酶、金属离子等的相互影响关系,将是土壤重金属植物修复的另一重要领域。

The accumulation of Cd in Huttuynia cordata and its promotion by rhizospheric microbes

Contaminated in soil with cadmium,which is highly toxicity to humans and animals,is widespread.Plant-microorganism combined bioremediation was used in this study in order to investigate the Cd accumulating capability of Huttuynia cordata induced by rhizospheric microbes.In this study,we compared the cadmium biosorption by H.cordata which was treated with or without microbes of high tolerance of Cd at different cadmium concentrations（50 and 200 mg·L^-1）.The Cd concentration of 200 mg kg^-1 in the soil had the most important effect on the amount of accumulation in shoots and roots of H.cordata,which was approximately 20-fold and 50-fold compared to that of the control,respectively.Moreover,When the concentration of Cd is 50 mg·kg^-1 in dry weight soil,the ratio of total Cd accumulation in shoots/roots is 2.5 in the plants with the microbial treatment,,while only 1.5 in the control without microbial treatment.Based on our study,the rhizospheric microbes were found to enhance the translocation of Cd from roots to shoots,which would then be multiplied when the concentration of total Cd in soil was much higher.Therefore,our result suggested that,the plant H.cordata has a great capacity to accumulate Cd contamination from soil and has a better effect on the Cd uptake enhanced by the rhizosphere microbes.The present study provided a novel,effective and environment-friendly method to cure the contamination.The research of rhizospheric microbes will gain a great development because of its convenient and low-price,and be used widely.