土壤原生生物的生态功能及其影响因素

Ecological function of soil protists and the influence factors

【目的】土壤原生生物是指土壤中除植物、动物和真菌以外的所有真核生物,具有明显的系统发育和功能多样性特征,是地下生态系统的关键组成部分之一。与原核生物(细菌与古菌)和真菌相比,原生生物在土壤食物网中的作用常被忽视。本文系统论述了土壤原生生物的多样性及其生态功能,并综述了土壤养分、水分、pH、温度、重金属、微塑料等因子对土壤原生生物的影响,旨在阐明原生生物对土壤养分转化、土壤食物网和植物健康的生态作用及对主要环境因子的响应。【进展】土壤原生生物的数量、大小与形态各异,且营养级类群多样性丰富,它们可作为光合藻类、微生物捕食者、植物与动物的寄生者,在土壤食物网中扮演重要角色。光合型原生生物除潜在提高土壤氧浓度外,对陆地生态系统的碳储存具有重要贡献。消费型原生生物可通过捕食改变微生物群落,推动土壤微生物环,抑制植物病害,并提高植物性能。寄生型原生生物常被认为对宿主具有负面效应,如改变动物多样性,并引起植物病害。然而,寄生型原生生物对推动养分(如磷)循环也有贡献,且对植物的叶际细菌具有生防功能。总的来看,原生生物推动了陆地生态系统物质循环与能量流动向更高营养级的转移,并在土壤食物网中占据中心位置,发挥着关键生态功能。【展望】未来可从原生生物多样性特征及其维持机制、原生生物与其他土壤微生物或动物(如蚯蚓、线虫等)的互作与代谢关系、原生生物对土壤食物网物质循环与能量流动的贡献及相关影响因素进行深入研究。此外,原生生物生防剂的资源开发与应用,将利于缓解土壤与植物农药残留,也对保障土壤健康及其可持续利用与发展具有重要意义。

【Objectives】Soil protists refer to all the eukaryotes excluding plants,fungi and animals.Soil protists have distinct phylogenetic and functional diversity characteristics,and are one of the key components serving underground ecosystem.The roles of protists in soil food web,compared with bacteria and fungi,are often overlooked.In this paper,we reviewed the diversity and ecological functions of soil protists,summarized the effects of soil nutrients,water,pH,temperature,heavy metals and microplastics on soil protists.The purpose of this study is to clarify the ecological effects of soil protists on nutrient transformation,soil food web and plant health,and their responses to the main regulatory factors.【Advances】Soil protists are varied in number,sizes and morphologies,showing wide diversity of trophic groups.They are active players in soil food webs as phototrophic algae,microbiome predators,and plant and animal parasites.Photosynthetic protists can potentially increase soil oxygen concentrations and contribute significantly to carbon storage in terrestrial ecosystems.Consuming protists are found efficient to alter microbial communities,drive soil microbial loops,suppress plant diseases and improve plant performance by predation.Parasitic protists are generally considered to have negative effects on the host,such as changing animal diversity and causing plant diseases.However,parasitic protists also contribute to the promotion of nutrient turnover(e.g.phosphorus),as well as the biological and protective function of phyllosphere bacteria.On the whole,the protists drive the circulation of matter and the flow of energy towards higher trophic levels in terrestrial ecosystems and play a central role in soil food webs and key ecological functions.【Forecast】Future researches should focus on the characteristics of protist diversity and their maintenance mechanism,the interactions and metabolism relationships between soil protists and other microorganisms and fauna(such as earthworms and nematodes),the contributions of protists to nutrient cycle and energy flow in the soil food web,and the related influencing factors.Additionally,the development and application of protistan biocontrol agents will be beneficial to the alleviation of pesticide residues in soil and plants,which is of great significance for ensuring soil health and its sustainable utilization and development.