应用PLFA技术分析氮沉降对三江平原小叶章湿地土壤微生物群落结构的影响

Study on microbial diversity of Deyeuxiaangustifolia wetland under the simulation nitrogen depositions with the PLFA method in Sanjiang plain

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 understand the effects of nitrogen deposition on soil microbial community, this study analyzed the microbial diversity in Sanjiang Plain wetland by using the phospholipids fatty acids （PLFA） biomarkers. In May 2010, nitrogen deposition plat was established in the Sanjiang Plain field experiment station of the institute of Nature ＆ ecology, Heilongjiang Academy of Sciences. Nitrogen loadings were designed at 3 levels such as N1, N2, N3 at the doses of 0, 4 and 8 g N·m^-2 a^-1, respectively. After four years treatment, soll samples were collected with a soll drill. The result showed that a total of 75 PLFAs were detected, and among them the characteristic fatty acids were 29 kinds. The analysis on type and content of the characteristic fatty acids indicated that eucaryon microorganism was the predominant group in the plot soil treated with all nitrogen treatments. In different nitrogen treatment plots, the range of soil microbial biomass with characteristics of total PLFAs content was 30 - 33 nmol.gt. The amount of fungus were significant different （P〈0.05） and the amount of bacteria were not （P 〉 0.05） in different nitrogen deposition treatments. In the low nitrogen deposition treatment, the PLFAs of soil microorganisms had the highest quantity and diversity, but in the high nitrogen deposition treatment the PLFAs of soil microorganisms had the lowest quantity and diversity. According to the Canonical Correlations, ammonium nitrogen and nitrate nitrogen in soil were positively correlated with the fungus. In conclusion, adding nitrogen will promote the growth of microorganisms, lowest nitrogen treatment is highest and control is the lowest. Ammonium nitrogen and nitrate nitrogen were main factors influence the amount of soil microorganism, which low nitrogen would promote soil microbial diversity and high nitrogen would restrain the soil microbial diversity.