模拟氮沉降对温带森林土壤线虫群落组成和代谢足迹的影响

Abstract

PDF HTML阅读 XML下载 导出引用 引用提醒 模拟氮沉降对温带森林土壤线虫群落组成和代谢足迹的影响 DOI: 10.5846/stxb201606231225 作者: 作者单位: 作者简介: 通讯作者: 中图分类号: 基金项目: 国家自然科学基金项目（31170484） Effects of simulated nitrogen deposition on temperate forest soil nematode communities and their metabolic footprints Author: Affiliation: Fund Project: 摘要 | 图/表 | 访问统计 | 参考文献 | 相似文献 | 引证文献 | 资源附件 | 文章评论 摘要:已有研究表明氮沉降可显著影响土壤线虫群落组成和多样性。然而，目前大多数研究集中在无机氮沉降的影响，而对于不同氮素形态对土壤线虫群落影响的研究还不是很清楚。利用运行5年的模拟氮沉降试验平台，开展了4个氮添加处理即对照（无氮添加，CK）、无机氮（硝酸铵，IN），有机氮（尿素和甘氨酸1：1混合，ON）和混合氮（无机氮和有机氮7：3混合，MN）添加对温带森林土壤线虫群落组成和多样性的影响研究，采用浅盘法分离线虫，土壤性质如pH、含水量、全碳全氮分别采用电位法、烘干法和元素分析仪法进行测定，应用营养类群组成、区系分析和代谢足迹分析不同形态氮沉降下土壤线虫群落结构特征。共分离线虫50个属，其中在CK样地中共发现29个属，在IN，ON和MN处理中分别发现线虫属37个，34个和29个，盘旋属Rotylenchus和大节片属Macroposthonia在所有处理中均为优势属。结果表明，与CK相比，IN处理、ON处理和MN处理均显著增加了土壤硝态氮含量。与无机氮相比，混合氮处理显著降低了食真菌线虫数量，有机氮处理显著增加了捕食杂食性线虫数量。与对照相比，无机氮处理显著增加了线虫多样性指数（H'），IN处理的均匀度指数（J）显著高于CK和MN处理，混合氮处理对应的优势度指数（λ）显著高于其他3个处理。在CK和ON处理，线虫的结构指数（SI）较高，富集指数（EI）较低，表明这两个处理的土壤受干扰程度较小，食物网处于结构化状态。在IN和MN处理，土壤线虫富集指数和结构指数均较高（>50），表明食物网稳定成熟。食真菌线虫代谢足迹和生物量碳在无机氮处理最高。有机氮和混合氮处理显著增加了捕食杂食性线虫代谢足迹和生物量碳。以上结果表明，不同氮素形态不仅对土壤线虫群落组成产生了影响，而且其代谢足迹也发生了显著的变化，这一结果有助于揭示温带森林对氮沉降的响应机制。 Abstract:Previous studies have shown that nitrogen deposition has a significant effect on the composition and diversity of soil nematode community. However, most studies focused on the effect of inorganic nitrogen, and the influences of different forms of N on soil nematode communities remained unclear. Based on the five-year simulated N-deposition experiment, we investigated the effects of N deposition on soil nematode communities. Four treatments, including the control (no nitrogen addition; CK), inorganic N (NH4NO3; IN), organic N (urea and glycine 1:1; ON), and mixed nitrogen (inorganic and organic N at the ratio of 7:3, MN), were studied. The soil nematodes were collected using the shallow basin method. The soil chemical properties, such as pH, potentiometry, soil water content (oven drying method) and elemental composition, were tested. The trophic composition, funnel analysis, and metabolic footprints were analyzed to understand the effect of different forms of N on soil nematode functional diversity. A total of 50 genera were classified. Of these 29, 37, 34, and 29 genera were included in the CK, IN, MN, and ON treatments, respectively. Rotylenchus and Macroposthonia were the dominant groups in all treatments. The results showed that IN, ON, and MN significantly increased the content of nitrate nitrogen compared with CK. The total numbers of nematodes in all treatments were not significantly different. MN significantly decreased the abundance of fungivores compared with IN, while ON increased that of omnivores-predators. Compared with CK, the IN treatment increased the diversity index (H') of soil nematodes. Furthermore, IN significantly increased the evenness index (J') compared with CK and MN. The dominance index (λ) was the highest in the MN treatment, and the nematode channel ratios in all treatments were more than 0.75, indicating that the process of soil decomposition occurs mainly through a bacterial-based energy channel. The results of the nematode funnel analysis indicated that the structure index in the CK and ON treatments was high, while the enrichment index was low, showing that the degree of interference was low and the soil food-web tended to be structured. The enrichment and structure indices of nematode communities in the ON and MN treatments were more than 50, indicating the stability of food web in the soil. The metabolic footprint and biomass carbon of fungivores were the highest in the IN treatments among all treatments. ON and MN significantly increased the metabolic footprint and biomass carbon of omnivores-predators. All results indicated that N deposition with different forms of nitrogen fertilization affected not only the composition of a soil nematode community, but also its metabolic footprints. Our findings contribute to understanding the response mechanism of temperate forests to nitrogen deposition. 参考文献 相似文献 引证文献