乙草胺和甲胺磷对农田黑土可培养真菌数量及种群结构的影响

应用传统及PCR-DGGE方法(denaturing gradient gel electrophoresis)，分别对不同浓度乙草胺、甲胺磷胁迫下黑土中可培养真菌CFU(colony forming units)、种群丰富度(richness)及种群结构动态变化规律进行了研究.结果表明,在实验室微域条件下，乙草胺对黑土可培养真菌CFU的影响随处理浓度的增加而抑制作用增强，表现出由低浓度(50 mg·kg^-1)时的刺激生长到高浓度(250 mg·kg^-1)时的长期抑制效应；250 mg·kg^-1甲胺磷在8周处理过程中对土壤可培养真菌生长具有显著的刺激效应，使可培养真菌CFU比对照增加10倍，但50和150 mg·kg^-1甲胺磷处理对土壤可培养真菌CFU无显著影响.种群丰富度系数分析结果表明,高、中浓度乙草胺处理可使土壤可培养真菌种群丰富度不可逆地降低.土壤真菌rDNA特异PCR-DGGE聚类分析结果表明,不同浓度乙草胺、甲胺磷处理均不同程度地对土壤可培养真菌的种群组成和结构造成影响，其中甲胺磷尤为显著.

Effects of acetochlor and methamidophos on culturable fungal population and community structure in black soil

By the methods of CFU and rDNA-PCR-DGGE, this paper studied the dynamic changes of culturable fungal populations, community structure, and population richness in black soil under stress of acetochlor and methamidophos. The results showed that the growth of fungi was promoted under lower concentration acetochlor (50 mg x kg(-1)), but long-standing inhibited under its higher concentration (250 mg x kg(-1)). 250 mg kg(-1) methamidophos promoted the growth of culturable fungi intensively during 8-week period, resulting in 10 times increase in CFU of fungi than the control, while low concentration methamidophos (50 mg x kg(-1)) had no evident effect. The richness of culturable fungi in soil treated by medium and high concentration acetochlor was decreased irreversibly. Cluster analysis of fungal rDNA-PCR-DGGE fingerprints profile showed that acetochlor and methamidophos could change the culturable fungal community structure diversely, and the effect of methomidophos was more obvious.