纤毛虫原生动物对戈壁土壤团聚体变化的生态响应——以河西走廊中部为例

Ecological response of ciliate protozoa to soil agglomerates in the desert Gobi region:a case study in the central Hexi Corridor

选择河西走廊中部戈壁土壤样品并进行过筛处理,旨在探究荒漠生态系统中土壤纤毛虫原生动物蕴藏量以及不同粒级土壤团聚体和纤毛虫种类/类群与丰度间的相关关系,同时分析比较完全培养计数法与Foissner计数法统计原生动物的效率,探讨纤毛虫原生动物在不同土壤粒径中的分布和演替规律。结果表明:①完全培养计数法获取的纤毛虫总丰度为Foissner计数法的16.5倍,培养第10天纤毛虫总类群数为Foissner计数法的2倍;②不同粒级土壤团聚体中纤毛虫总丰度随着土壤粒径的减小而增大,100目土样纤毛虫丰度是原位土样的3.4倍,原位和10目土样获得的纤毛虫总种类/类群数均高于颗粒和100目土样;③土壤pH和水分扰动是导致纤毛虫丰度变化的主导因素;④在“非淹没培养皿法”过程中,土壤纤毛虫群落呈现“低等-高等-低等”的演替规律。土壤团聚体作为土壤最重要的结构体,对维持土壤中的微生物群落结构和酶活性有着重要的作用,建议今后对荒漠生境土壤进行纤毛虫分类学研究时,针对不同类群或目标种尝试进行土壤样品的过筛处理或复检日期的匹配化选择。完全培养计数法不仅能够记录“非淹没培养皿法”实验过程中各种类/类群的数量和丰度,还可追踪土壤纤毛虫群落演替,得出物种蕴藏量的“理论丰度峰值”,同时分析各种类/类群与理化因子间的相关关系,为抑纤毛虫作用“Ciliatostasis”的研究提供理论依据。

In order to explore the abundance of soil ciliates in desert ecosystems,as well as the correlation between different soil aggregates,ciliate species/groups,and abundance,we collected soil samples from the central part of the Hexi Corridor,with sieving treatment.By analyzing and comparing the efficiency of the culture counting method and the Foissner counting method for quantifying protozoa,we also investigated the distribution and succession patterns of soil ciliates among different soil particle sizes.Results are as follows:①The total abundance of ciliates obtained by the complete culture counting method was 16.5 times higher than that of the Foissner counting method,and the total number of ciliate taxa in the 10th day of culture was twice as high as that of the Foissner counting method;②The total abundance of ciliates in soil aggregates of different grain sizes increased with the decrease of soil grain size.The abundance of ciliates in the 100-mesh soil sample was 3.4 times higher than that of the subsoil sample,while the abundance of ciliates in the in situ and 10-mesh soil samples increased with the decrease of soil grain size.The total number of ciliate species/taxa obtained from in situ and 10-mesh soil samples were higher than those from granular and 100-mesh soil samples;③The soil pH and moisture disturbance were the dominant factors in the change of ciliate abundance;④In the process of“non-submerged Petri dish method”,the soil ciliate community showed a low-high-low pattern.As the most important structure of soil,soil aggregates play an important role in maintaining the structure of microbial community and enzyme activity in soil.It is suggested that when ciliate taxonomic research is carried out on soil in desert habitats in the future,the sieving of soil samples or the matching of re-examination dates should be tried for different taxa or target species.The complete culture counting method can not only record the number and abundance of various classes/taxa during the“non-submerged Petri dish”experiment,but also track the soil ciliate community succession,derive the“theoretical peak abundance”of species,and analyze the correlation between various taxa/groups and physico-chemical factors,as well as the relationship between ciliates and the physical and chemical factors.At the same time,we can analyze the correlation between various species/classes and physicochemical factors,which can provide a theoretical basis for the study of“Ciliatostasis”,a ciliatostatic effect.