论文部分内容阅读
贡嘎山东坡自下而上分布着从亚热带到寒带的连续气候带及从常绿阔叶林到针叶林的连续植被类型,其地下土壤线虫群落的分布格局尚不清楚,为研究其不同气候带间的土壤线虫群落特征及其在垂直气候带间的变化趋势,2014年9月和12月对贡嘎山东坡5个气候带土壤线虫进行了2次调查.研究结果为:共捕获土壤线虫193 921条,隶属于2纲9目68科172属,平均密度2 155条/100 g干土,食细菌线虫为优势营养类群.不同气候带间土壤线虫群落结构差异性各异,并受季节变化影响;影响群落结构的主要类群是色矛目(Chromadorida)、窄咽目(Araeolaimida)、小杆目(Rhabditida)和单齿目(Mononchida).线虫群落密度及多样性指数在不同气候带间均无显著差异,但12月的密度显著高于9月,而多样性指数则显著低于9月.除食细菌线虫外,食真菌、捕食-杂食和植物寄生线虫的密度在不同气候带间(随海拔升高)呈先增加后下降趋势(P<0.05),且有显著季节差异(P<0.05).从亚热带到寒温带,土壤线虫的基础指数(BI)逐渐下降(P<0.05),成熟度指数(MI)逐渐增加(P<0.05),表明生态系统的抵抗力逐渐降低而成熟度逐渐增加;通道指数(CI)呈波动性下降(P<0.05),且均小于50,表明碎屑食物网以细菌分解途径为主;植物寄生成熟度指数(PPI)无明显变化趋势(P>0.05),但9月份显著高于12月份,表明9月份土壤生态系统比12月份更成熟.线虫群落密度、生态指数(BI、MI)、营养类群(PO、Pl)分别与土壤有效氮、全钾和土壤温度呈显著相关(P<0.05).综上表明气候带类型变化对土壤线虫群落密度和多样性影响较弱,对土壤线虫群落结构及生态指数影响较大,土壤有效氮、全钾及温度是主要影响因子.
The continuous climatic zone from subtropical zone to boreal zone and the continuous vegetation type from evergreen broad-leaved forest to coniferous forest are distributed on the east slope of Gongga Mountain from bottom to top. The distribution pattern of underground soil nematode community is unclear. The characteristics of soil nematode communities in the climatic zone and their trend of variation in the vertical climatic zone were investigated in 5 climatic zones on the east slope of Gongga Mountain in September and December 2014. The results were as follows: 193 921 nematodes belong to 2 genera and 9 orders, 68 families and 172 genera, with an average density of 2 155 per 100 g of dry soil and bacteria-eating nematode as dominant nutrition group.The soil nematode community structure varies in different climates and is affected by The dominant species affecting the community structure were Chromadorida, Araeolaimida, Rhabditida and Mononchida. The density and diversity index of nematode community varied in different climatic zones There was no significant difference between December and December, but the density in December was significantly higher than that in September, while the diversity index was significantly lower than in September. The density of fungi, prey-omnivorous and parasitic nematodes were significantly higher in different climates Room (with altitude) was first (P <0.05), and there was a significant seasonal difference (P <0.05). From the subtropical zone to the cold temperate zone, the basal index of soil nematodes decreased gradually (P <0.05) and the maturity index (P <0.05), indicating that the ecosystem resistance gradually decreased and the maturity increased gradually; the channel index (CI) showed a fluctuant decrease (P <0.05), and both were less than 50, indicating that the bacterial foodstuff network (P> 0.05), but it was significantly higher in September than in December, indicating that the soil ecosystem in September was more mature than that in December. The density of nematode community, ecological index (BI , MI) and nutrition groups (P0, P1) were significantly correlated with available nitrogen, total potassium and soil temperature, respectively (P <0.05) .To sum up, the changes of climatic belt types have little effect on soil nematode community density and diversity, Soil nematode community structure and ecological index greater impact on soil available nitrogen, total potassium and temperature are the main impact factors.