三峡库区消落带狗牙根及土壤生态化学计量特征的空间分异及相关性  

Spatial Differentiation and Correlation of Ecological Stoichiometric Characteristics of Cynodon dactylon and Soil in the Water-level Fluctuation Zone of the Three Gorges Reservoir Area

作　　者：许丽雯 张跃伟 蹇陈 张媛媛 王晓锋 XU Liwen;ZHANG Yuewei;JIAN Chen;ZHANG Yuanyuan;WANG Xiaofeng(College of Geography and Tourism,Chongqing Normal University,Chongqing 401331,China;Chongqing Key Laboratory of Carbon Cycle and Carbon Regulation in Mountainous Ecosystems,Chongqing 401331,China;Chongqing Field Observation and Research Station of Earth Surface Ecological Processes in Three Gorges Reservoir Area,Chongqing 405400,China;Institute of Design,Chongqing Industry Polytechnic College,Chongqing 401120,China)

机构地区：[1]重庆师范大学地理与旅游学院,重庆401331 [2]山区生态系统碳循环与碳调控重庆市重点实验室,重庆401331 [3]三峡库区地表生态过程重庆市野外科学观测研究站,重庆405400 [4]重庆工业职业技术学院设计学院,重庆401120

出　　处：《水土保持学报》2025年第1期249-261,共13页Journal of Soil and Water Conservation

基　　金：重庆市教委科技项目(KJQN202200536,KJQN202203222);国家自然科学基金项目(41807321);重庆市自然科学基金项目(2022NSCQ-MSX2598)。

摘　　要：[目的]狗牙根(Cynodon dactylon)是当前三峡库区消落带植物群落的建群种,为研究狗牙根与土壤生态化学计量特征的空间分异格局及关联关系,认识消落带养分循环及物种适应特征。[方法]通过对三峡消落带(巴南-秭归段)16个断面分布的狗牙根及其覆盖区的土壤进行野外采样,分析植物各器官(根、茎、叶)及土壤中碳、氮、磷质量分数,探究狗牙根及其实生土壤生态化学计量特征的空间分异规律及相互关系。[结果]1)消落带土壤具有明显的“贫氮富磷”特征,且养分质量分数及其计量比具有强烈的空间分异,土壤有机碳、全氮、全磷、碳氮比、碳磷比等自上游向下游呈升高趋势,而氮磷比(N/P)相对稳定;2)从库区上游至下游,狗牙根各器官C质量分数均呈降低趋势,而N、P质量分数自上游至下游则呈明显增加趋势,与下游消落区沉积增强导致的土壤养分供应水平提高有关;其中,叶片N质量分数表现出一定的空间稳定性,土壤贫N条件下狗牙根具有高效的N吸收效率并优先保障其叶片N需求的能力;3)狗牙根各器官化学计量比空间分异总体较弱,但根、茎的C/N、C/P的变异性强于叶片,表明狗牙根形成优先维持叶片生理功能稳定的适生策略;4)狗牙根与土壤的养分质量分数具有显著相关性,土壤N供应水平是制约狗牙根养分质量分数变化的关键因素;然而,二者的化学计量比相关性不显著,表明水淹和植物内稳性共同调节下,狗牙根与实生土壤间并未形成相对一致的化学计量特征;5)内稳性指数表明,消落带狗牙根内稳性总体较好,但上游向下游趋于减弱。[结论]在水淹格局变化背景下,狗牙根及土壤养分质量分数特征均呈明显的空间分异及协同关联,土壤养分的空间演化对狗牙根生态化学计量特征有重要影响;狗牙根化学计量比空间分异相对较弱,能够通过调节自身养分需求策略提高其对变[Objective]Cynodon dactylon is an important component and the dominant species in the ecosystem of the water-level fluctuation zone(WLFZ)of the Three Gorges Reservoir,the largest hydropower project in the word.Investigation on the spatial distribution patterns and correlations of nutrient and stoichiometric characteristics between C.dactylon and its periradical soil is of significant importance in comprehending nutrient cycling as well as species adaptation features within the WLFZ.[Methods]A field investigation of C.dactylon and its periradical soil across 16 sections in the WLFZ of the Three Gorges Reservoir Area from Banan to Yichang was conducted.The carbon,nitrogen,and phosphorus contents in plant organs(roots,stems and leaves)and soil were analyzed to explore the spatial heterogeneity and interrelationships of the ecological stoichiometric characteristics between C.dactylon and soil.[Results]1)The soil in the WLFZ associated with C.dactylon demonstrated a distinct“nitrogen-poor and phosphorus-rich”characteristic with significant spatial variations in nutrient contents and stoichiometric ratios.Specifically,soil organic carbon,total nitrogen,total phosphorus,C/N ratio,and C/P ratio exhibited a consistent increase from the upstream to the downstream sections,while N/P ratio was relatively stable.2)From the upstream to the downstream of WLFZ,carbon contents in various organs of C.dactylon exhibited a decreasing trend,while nitrogen and phosphorus contents showed significant increasing patterns,likely due to intensified sedimentation and the resultant higher soil nutrient supply levels in the downstream WLFZ with the prolonged flooding time.Notably,nitrogen content in the leaves demonstrated a degree of spatial stability,suggesting that C.dactylon could absorb nitrogen efficiently and meet its leaf nitrogen requirements preferentially under nitrogen-deficient conditions.3)Generally low variations in the stoichiometric ratios in organs of C.dactylon were found.However,the variability in C/N and C/P ratios in

关 键 词：三峡库区 消落带 狗牙根 生态化学计量 空间分异 

分 类 号：S714.1[农业科学—林学]