黄土高原水蚀风蚀交错区固氮微生物群落多样性在生物结皮中的演变规律  

Diazotrophic community diversity in the succession development of biological soil crusts in water⁃wind erosion crisscross region of the Loess Plateau

作　　者：焦冰洁 徐琳 李香真[3] 张丙昌 JIA0 Bingjie;XU Lin;LI Xiangzhen;ZHANG Bingchang(Shanxri Normal University School of Geographical Sciences,Taiyuan 030031,China;Ecological Enironment Research Center of the Middle Yellono River,Shanxi Normal Unirersity,Taiyuan 030031,China;Chengdu Institute of Biology,Chinese Academy of Sciences,Chengdu 610041,China;Instiute of ecological Forestry,Sichuan Agriculural Unitersity,Chengdu 611100,China)

机构地区：[1]山西师范大学地理科学学院,太原030031 [2]山西师范大学黄河中游生态环境研究中心,太原030031 [3]中国科学院成都生物研究所,成都610041 [4]四川农业大学生态林业研究所,成都611100

出　　处：《生态学报》2023年第23期9662-9673,共12页Acta Ecologica Sinica

基　　金：国家自然科学基金项目(42271067,U2003214)。

摘　　要：生物土壤结皮在黄土高原的水土保持、养分补给等方面发挥着重要生态功能。固氮微生物是固氮过程的关键功能群,影响着土壤氮素平衡,然而黄土高原水蚀风蚀交错区严重的水土流失导致土壤养分大量损失,尤其是氮素。该区域生物结皮广泛发育,它们在干旱半干旱区土壤氮素积累过程中起着重要作用。但是该区域生物结皮不同发育阶段中的固氮潜力、固氮微生物群落多样性及其关键环境控制因子尚不清楚。以黄土高原水蚀风蚀交错区为研究区,三种生物结皮类型和裸地对照为研究对象,采用Illumina HiSeq平台对nifH基因扩增产物进行生物信息学分析,揭示了固氮潜力及微生物群落多样性的分布规律。结果表明,生物结皮演替显著影响固氮酶活性、nifH基因丰度和固氮微生物α-多样性,各值均在苔藓结皮最高,显著高于其它演替阶段,且生物结皮层高于结皮下层土壤。在固氮微生物群落组成上,裸地以变形菌门的红螺菌目、酸硫杆菌目和根瘤菌目为主;而在藻结皮、地衣结皮和藓结皮阶段,均表现为蓝藻门的念珠藻目占绝对优势,是固氮微生物的关键类群,其中Trichormus、念珠藻属是优势固氮物种;与藻结皮、地衣结皮相比,藓结皮中念珠藻目的相对丰度显著降低,而变形菌门的红螺菌目、酸硫杆菌目和根瘤菌目的丰度明显上升。除此之外,蓝杆藻属、鱼腥藻属、斯克尔曼氏菌属、瘤胃梭菌属在藻结皮、地衣结皮、藓结皮也占明显优势。念珠藻目以及Trichormus的丰度与固氮酶活性、nifH基因丰度呈显著正相关关系,而与红螺菌目、酸硫杆菌目、梭菌目、根瘤菌目呈显著负相关;Trichormus相关的物种在黄土高原生物结皮氮输入过程中可能发挥着关键作用。生物结皮演替通过改变土壤pH值、有机质、全氮、含水量等理化特征而影响了微生境,通过环境筛选和物种重排作用�Biological soil crusting(BSCs)plays an important ecological function in water and soil retention,nutrient resupply in the Loess Plateau.Nitrogen fixing microorganisms are the key functional group for soil nitrogen fixation process and affect the soil N balance,however,the severe soil loss in the hydro erosive and erosive staggered zones of the Loess Plateau resulted in substantial loss of soil nutrients,especially N.BSCs develop widely in this region,and they play an important role in the process of nitrogen accumulation in soils in arid semi-arid regions.But the nitrogen fixation potential,diversity of nitrogen fixing microbial community and its key environmental control factors in different developmental stages of biological nodulation in this region are still unclear.Here,we used the Illumina hiseq platform to perform bioinformatics analysis of the amplified products of the nifH gene to reveal the distribution pattern of the nitrogen fixation potential and diversity of the microbial community,using the loess plateau water cavitation interlace as the research area,three biological crusting types and nude ground controls.The results showed that the BSCs succession significantly changed the nitrogenase activity(NAc),nifH gene abundance,andα-diversity of diazotrophs,while these parameters were significantly higher in moss crusts than those in bare soil,light and dark algal crusts,and lichen crusts.They also showed higher values in 0—2 cm biocrust layer than those in subsurface soil below BSCs.Diazotrophic community in bare soil was dominated by Rhodospirillales,Acidithiobacillales,and Rhizobiales of phylum Proteobacteria.Nostocales belonging to Cyanobacteria were the dominant diazotrophs in algal crusts,lichen crusts,and moss crusts.Trichormus and Nostoc were keystone species in Nostocales.However,compared with algal crusts and lichen crusts,the relative abundance of Nostocales significantly decreased and the relative abundance of Rhodospirillales,Acidithiobacillales,and Rhizobiales increased in moss crusts.Bes

关 键 词：黄土高原 水蚀风蚀交错区 生物结皮演替 固氮微生物 

分 类 号：Q938.1[生物学—微生物学]