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为了研究氮沉降对三江湿地土壤微生物群落结构的影响,利用磷脂脂肪酸技术(PLFA)对三江平原小叶章湿地土壤微生物多样性进行了分析。2010年5月,在黑龙江省科学院自然与生态研究所三江平原湿地生态定位研究站内的小叶章湿地中建立模拟氮沉降试验平台,设置3个氮沉降浓度梯度:N1(0 g N·m-2a-1)、N2(4 g N·m-2a-1)、N3(8 g N·m-2a-1),于2014年6月用土钻进行土壤样品采集。结果表明:本研究共检测到PLFAs 75种,其中特征脂肪酸29种。不同氮沉降处理下,真菌群落的生物量较高,土壤微生物生物量的总量介于30~33nmol·g-1。氮沉降增加对真菌群落数量的影响比较显著(P<0.05),但是对细菌和放线菌影响并不显著。低氮时土壤微生物的数量最多,对照最低;高氮时土壤微生物群落的多样性值和丰度值最高。根据典型性相关分析,得出铵态氮和硝态氮对土壤中真菌含量影响较为显著。通过本研究可以得出,施氮增加了土壤微生物总量。铵态氮和硝态氮是影响土壤微生物数量的主要因子,低氮增加了土壤微生物多样性,高氮则产生抑制作用。
In order to study the effect of nitrogen deposition on soil microbial community structure in Sanjiang wetland, the microbial diversity of soil in the Calamagrostis angustifolia wetland in Sanjiang Plain was analyzed by PLFA. In May 2010, a simulated nitrogen deposition test platform was established in the Oxytropis falcata wetland in the Sanjiang Plain wetland eco-location research station of the Institute of Nature and Ecology, Academy of Sciences of Heilongjiang Province. Three nitrogen deposition concentration gradients were set up: N1 (0 g N · m-2a Soil samples were collected by soil drilling in June 2014 with N2 (4 g N · m-2a-1) and N3 (8 g N · m-2a-1). The results showed that 75 species of PLFAs were detected in this study, including 29 kinds of characteristic fatty acids. Under different nitrogen deposition treatments, the biomass of the fungal community was higher, and the total amount of soil microbial biomass was between 30 and 33 nmol · g-1. The effect of increasing nitrogen deposition on the number of fungal communities was significant (P <0.05), but the effect on bacteria and actinomycetes was not significant. Soil nitrogen was the most abundant in the low nitrogen and lowest in the control. The highest diversity and abundance were observed in the soil microbial community under high nitrogen. According to the canonical correlation analysis, it is concluded that the effect of ammonium nitrogen and nitrate nitrogen on the fungi content in soil is significant. It can be concluded from this study that nitrogen application increased the total amount of soil microbes. Ammonium nitrogen and nitrate nitrogen are the main factors that affect the amount of soil microorganisms. Low nitrogen increases soil microbial diversity and high nitrogen inhibits them.