摘要
生物土壤结皮在增强土壤抵抗水蚀风蚀能力、改善土壤养分等方面发挥着重要作用,土壤胞外酶活性可作为土壤生化反应强度的微生物指标,对理解荒漠生态系统微生物参与的养分循环过程具有重要意义。选取黄土高原神木县六道沟小流域5个生物结皮发育阶段(裸沙地、全藻结皮、藻-藓混生结皮、藓-藻混生结皮、全藓结皮)的土壤作为研究对象,研究生物结皮发育过程中土壤胞外酶活性(β-1,4-葡萄糖苷酶、β-1,4-N-乙酰基氨基葡萄糖苷酶、亮氨酸氨基多肽酶和碱性磷酸酶)及其化学计量的变化特征。结果表明:(1)土壤4种胞外酶活性均随生物结皮发育序列变化显著增加,全藓结皮土壤显著大于全藻结皮土壤(P<0.05)。(2)生物土壤结皮层胞外酶活性显著高于下层土壤,且胞外酶活性随着土层深度的加深不断降低。(3)相关性分析表明,土壤C、N、P、土壤C:P、土壤N:P均与土壤胞外酶活性呈极显著正相关关系(P<0.05)。(4)有结皮覆盖土壤的养分含量及土壤胞外酶活性显著高于裸沙地,全藓结皮土壤的养分含量及土壤胞外酶活性显著高于全藻结皮土壤。(5)标准化主轴估计表明,土壤胞外酶活性随着生物结皮的发育均有明显增强并呈现稳态特征,N-获取酶和P-获取酶相对于C-获取酶之间的斜率呈现等容关系,这一结果表明土壤微生物通过稳态调控胞外酶化学计量特征,在干旱半干旱生态系统养分循环过程中具有重要作用。
Biological soil crusts(BSCs)play an important role in enhancing soil resistance to water and wind erosion,and improving soil nutrients.Soil extracellular enzyme activity can be used as a microbial indicator of the intensity of soil biochemical reactions,which is important for understanding the nutrient cycling processes involving microorganisms in desert ecosystems.However,there is a lack of understanding of the variation in soil extracellular enzymes and their stoichiometry during the formation of BSCs on the Loess Plateau.Soils from five biological crust formation stages(CK,A,AM,MA,and M)in Liudaogou watershed,Shenmu County,on the Loess Plateau were selected for the study.Soil extracellular enzyme activities[β-1,4-glucosidase(BG),β-1,4-N acetylaminoglucosidase(NAG),leucine aminopeptidase(LAP),and alkaline phosphatase(AP)]and their stoichiometric changes during the formation of biocrusts were characterized.The activities of soil BG,NAG,LAP,and AP increased significantly with the sequence of biological crust development,and activity was significantly greater in Mo soil than that in Al soil(P<0.05).Extracellular enzyme activities were significantly higher in the BSCs layer than those in the lower soil layer,and decreased continuously with the depth of the soil.Soil C,N,P,C:P,and N:P all showed highly significant positive correlations with soil extracellular enzyme activities(P<0.05).The nutrient content and soil extracellular enzyme activity of soil with crust cover were significantly higher than those of bare land,and those of Mo soil were significantly higher than those of Al soil.Standardized major axis estimates indicated that soil extracellular enzyme activities were significantly enhanced and showed homeostasis with formation of biological crusts,and the slopes between N-and P-acquiring enzymes relative to C-acquiring enzymes showed isotropic relationships.Soil microorganisms play an important role in nutrient cycling in arid and semi-arid ecosystems through homeostatic regulation of extracellular enzyme stoichiometry.
作者
姚宏佳
王宝荣
安韶山
杨娥女
黄懿梅
YAO Hongjia;WANG Baorong;AN Shaoshan;YANG E’nv;HUANG Yimei(State Key Laboratory of Soil Erosion and Dryland Farming on the Loess Plateau,Institute of Soil and Water Conservation,Northwest A&F University,Yangling 712100,Shaanxi,China;State Key Laboratory of Soil Erosion and Dryland Farming on the Loess Plateau,Institute of Soil and Water Conservation,Chinese Academy of Science and Ministry of Water Resources,Yangling 712100,Shaanxi,China;University of Chinese Academy of Sciences,Beijing 100049,China;Key Laboratory of Plant Nutrition and the Agro-Environment in Northwest China,Ministry of Agriculture,College of Natural Resources and Environment,Northwest A&F University,Yangling 712100,Shaanxi,China)
出处
《干旱区研究》
CSCD
北大核心
2022年第2期456-468,共13页
Arid Zone Research
基金
国家自然科学基金面上项目(41671280,41877074,42077072)资助。
关键词
生物土壤结皮
发育序列
胞外酶
化学计量
黄土高原
biological soil crusts
developmental sequence
extracellular enzymes
stoichiometry
Loess Plateau
作者简介
姚宏佳(1997-),女,硕士研究生,主要从事土壤微生物生态研究.E-mail:yaohj97@163.com;通讯作者:安韶山.E-mail:shan@ms.iswc.ac.cn。
