黄河三角洲新生湿地不同植被类型土壤的微生物分布特征

为探明黄河三角洲新生湿地土壤微生物分布特征,选取盐地碱蓬(Suaedasalsa)、柽柳(Tamarix chinensis)、芦苇(Phragmites communis)和拂子茅(Calamagrostis epigeios)4种湿地植被土壤,分春、夏、秋3个季节对其中细菌、真菌和放线菌数量组成和分布特征进行了研究。结果表明:不同植被类型湿地土壤中各类微生物数量差别明显,但总体上均偏少,而且优势种类非常明显,以细菌为主,放线菌居中,真菌最少;不同微生物数量上具有明显的季节分布特征,除拂子茅湿地细菌群落外,其他各群落数量均为夏季高,春、秋低;湿地土壤中微生物总量分布存在明显的根际效应,其中细菌的根际效应最为明显;土壤中氮和磷(总氮、总磷、速效氮、速效磷)含量对细菌的数量影响最明显;真菌分布与氮的含量关系密切,但与磷素关系不大;放线菌分布与氮含量相关性小,与磷素呈负相关;微生物数量与土壤pH值和电导率呈一定程度的负相关。本区土壤微生物分布与植被类型、土壤盐分和养分关系密切,且具有明显的季节动态。

Distribution Characteristics of Microbes in New-born Wetlands of the Yellow River Delta

In order to investigate the distribution characteristics of soil microbes in the Yellow River Delta′s new-born wetland,the composition and distribution of bacteria,fungi and actinomycetes were studied during spring,summer and autumn in four types of wetland soils growing Suaeda salsa,Tamarix chinensi,Phragmites communis and Calamagrostis arundinacea,respectively.Results indicate that the quantities of microorganism are different between wetland soils growing different types of plants.As a whole,the quantities of microorganism are less in wetland soil than normal soil.Among all microbes,bacteria were most numerous followed by actinomyces,with fungi the least numerous.The quantities of microorganisms vary with the seasonal changes;it is high in summer and low in spring and autumn,except for the Calamagrostis arundinacea community.Soil microorganisms were distributed around rhizosphere and much more commonly than the non-rhizosphere,especially for bacteria.Bacterial quantities were influenced by the concentrations of nitrogen and phosphorus of soil(total nitrogen,total phosphorus,available nitrogen,and available phosphorus).Fungi distribution was closely related to the concentration of nitrogen,but not phosphorus.Actinomycetes distribution was weakly related with nitrogen concentration,and had negative correlations to phosphorus concentrations of soil.The quantities of microorganisms showed negative correlation with pH and conductivity of soil to some extent.The distribution of microbes in soil was closly correlated with the vegetation type,concentrations of soil soluble salt,and soil nutrients.It had significant seasonal variations as well.