食微线虫对植物生长及土壤养分循环的影响

近二十多年来,土壤动物的生态功能受到广泛重视。越来越多的证据表明,土壤动物和微生物间的相互作用对土壤生态系统过程和植物生长起着重要的调节作用。本文综述了食细菌线虫和食真菌线虫对土壤微生物、土壤氮矿化和植物生长的影响。大量研究发现,食细菌线虫和食真菌线虫都有助于土壤氮素等养分矿化,从而促进植物生长。这种作用主要是线虫通过取食活动加速微生物周转,并通过代谢分泌和释放微生物所固持的养分而实现的。但这种作用会因不同的线虫、微生物和植物的种类以及土壤基质的C/N营养状况而异,此外还受线虫的营养类群及其与其他土壤动物之间复杂关系的影响。今后应该加强以下几方面的研究:(1)深入研究线虫、微生物和植物之间相互作用的机制;(2)增加控制实验系统的复杂性,研究线虫不同功能群之间及其与其他土壤动物之间的关系;(3)加强长期实验和观察,在较长的时间尺度上了解线虫的生态功能;(4)加强对不同生态系统的研究,在更大的空间尺度上综合了解土壤线虫的生态功能;(5)在全球气候变化的背景下了解土壤线虫的响应,并预测土壤线虫对全球变化的反馈。

Effect of microbivorous nematodes on plant growth and soil nutrient cycling: a review

The ecological functions of soil fauna have attracted widespread interest from ecologists during the past two decades. A growing number of evidences show that the soil fauna interact with microorganisms and play important roles in regulating soil ecosystem processes and plant growth. This review addresses the issue of how bacterial- and fungal-feeding nematodes influence soil microorganisms, nitrogen mineralization and plant growth. Most studies suggest that bacterial- and fungal-feeding nematodes stimulated soil nitrogen mineralization and promoted plant growth. The mechanisms underlying these effects are the impact of nematode grazing on microorganisms and the release of nutrients from consumed microbial biomass. However, these effects vary with different nematode species, microorganism species, plant species and C/N ratios of substrates, and are influenced by complex interactions between different trophic groups of nematodes as well as other soil fauna. Future studies should (1) enhance our understanding about the mechanistic basis of the interaction of nematodes, microorganisms and plants; (2) address more complex interactions between different trophic groups of nematodes and other soil fauna; (3) examine the ecological roles of soil nematodes at a longer temporal scale; (4) compare different ecosystems to understand the ecological roles of soil nematodes at a broader spatial scale; and (5) predict the responses and feedbacks of soil nematodes to atmospheric drivers of global changes.