锌胁迫对土壤中微生物群落变化的影响

摘要

采用多聚酶链式反应结合变性梯度凝胶电泳(PCR-DGGE)测试方法,对我国5种典型锌(Zn)污染土壤中的微生物进行了DGGE图谱分析,并通过戴斯矩阵方法和B-C矩阵2种方法对不同处理土壤中微生物群落相似性进行了测定,结合Vegan排序轴分析方法对Zn胁迫土壤中微生物结构及群落相似性与土壤性质间关系进行了研究.结果表明:Zn胁迫会引起土壤微生物数目和种类的降低,但并不是简单的负相关.土壤中微生物的多样性指数最大值出现在低浓度(200mg/kg处理)污染程度土壤中,说明Zn在低污染胁迫下,一定程度上会促进微生物群落数量的增加,丰富了群落结构多样性;高浓度(＞800mg/kg)Zn胁迫对微生物群落结构有明显抑制作用,不同处理土壤微生物Shannon指数下降范围为5.14％(公主岭黑土)～17.2％(杭州水稻土).通过戴斯矩阵分析土壤中微生物群落相似性结果表明,随着Zn浓度的增加,土壤中微生物群落相似性显著下降,最大降低23.3％,说明土壤中Zn胁迫在一定程度上改变了土壤微生物的群落结构.对土壤中影响Zn胁迫与微生物群落结构变化影响因子的相关性分析结果表明,影响微生物群落结构的主要因子为pH值＞OC＞CEC.%The soil microbial structure and community of five different kinds of contaminated soil were determined using PCR-DGGE test method,the soil microbial community and microbial similarity was measured and compared using Des matrix analy sis and B-C matrix analysis and the relationship between Zn toxicity to soil microbial structure and soil properties was also analysed by using Vegan Sorting Axis analysis.Zn pollution could decrease the number and type of microbial in soil,while it was not a simply negative correlation.The maximum value of soil microorganisms diversity indices were observed at low Zn addition level (200mg/kg) in soils,which implied that application of low concentration Zn in soils would contribute to the increased number of soil microbial community and enrich the community structure diversity,however,with the increment of Zn in soils,the microbial community structure were restrained at high Zn concentrations,the Shannon index decreased 5.14％ to 17.2％ among the treatments,the minimum value (5.14％) was observed in black soil from Gongzhuling and the greatest reduction was found in the paddy soil from Hangzhou.The soil microbial similarity as determined by Des matrix and B-C matrix analysis decreased significantly with Zn addition in high concentration (＞800mg/kg) in soils,with the maximum reduction of 23.3％,soil microbial community structure could be damaged after long time Zn stress in soils.Correlation analysis between the influencing factors of Zn stress and microbial community structure change in soils showed that the microbial community structure would be influenced by pH,followed by the OC,CEC in soils.