摘要
个体大小反映林木径向生长状况,细根对根际土壤环境变化具有高度敏感性,探讨不同大小个体的林木细根功能性状与根际土壤微环境之间的关系,有助于从个体水平揭示林木地下生态系统内的相互作用机制。该研究以11年生刨花楠(正名:刨花润楠,Machilus pauhoi)为对象,基于不同大小个体进行细根与根际土壤取样,分析不同大小刨花楠个体细根功能性状与根际土壤养分含量、微生物群落结构及酶活性的关系。结果表明:1)不同大小林木个体细根功能性状与根际微环境均存在差异,其中细根生物量、比根长、根长密度、根体积密度、根组织密度、根氮含量和根磷含量等指标差异显著,除比根面积和根组织密度外,其他各细根功能性状均以中等个体为最大,根际土壤碳氮磷含量也以中等个体刨花楠为最高。2)不同大小刨花楠个体细根比根长、根体积密度、细根生物量及根际土壤真菌、放线菌含量等性状变异系数较大,其中中等刨花楠个体变异系数相对较大,而小刨花楠个体相对较小,各大小个体都倾向于通过调节根体积密度、细根生物量及根际土壤真菌含量、硝态氮含量等性状以适应环境变化。3)不同大小个体细根采取的资源利用策略不同,中等刨花楠个体具有较大的比根长、根氮含量、根磷含量,采取资源获取型策略以优化其对养分的获取能力,根组织密度较大的小个体细根采取资源保守型策略以提升其应对环境胁迫的能力,而大个体细根则采取地上、地下协同生长的资源权衡策略。4)根际土壤微环境中的土壤全碳含量、微生物生物量碳含量、放线菌含量、铵态氮含量、酸性磷酸酶活性和微生物生物量氮含量是影响刨花楠细根功能性状的主要因子。不同大小刨花楠个体细根功能性状与根际微环境间关系存在差异。小刨花楠个体细根主要受根际土壤养分的影响;中等刨花楠个体细根主要受根际土壤中放线菌含量及酸性磷酸酶活性影响;而大刨花楠个体细根性状表现出既受根际土壤养分影响又受根际土壤微生物群落结构中细菌、放线菌含量影响的特征。研究结果可为开展刨花楠微地形造林、精确制定其人工林抚育间伐措施、培育大径材人工林等提供理论依据。
Aims Individual size reflects the radial growth of trees,while fine roots are highly sensitive to changes in the rhizosphere soil environment.Investigating the relationship between functional traits of fine root and the microenvironment of rhizosphere soil in trees at different sizes can contribute to elucidating interaction mechanisms within the forest subsurface ecosystem of trees at the individual level.Methods In this study,fine roots and rhizosphere soil sampling were conducted based on Machilus pauhoi individuals of different sizes in an 11-year-old plantation.The aim is to analyze the relationship between fine root functional traits,rhizosphere soil nutrients content,microbial community structure,and enzyme activities of M.pauhoi individuals of different sizes.Important findings The results indicate that:1)There are differences in fine root functional traits and rhizosphere microenvironment among trees of different sizes.Significant differences were observed in traits such as fine root biomass,specific root length,root length density,root volume density,root tissue density,root nitrogen content and root phosphorus content.Except for the specific root area and root tissue density,other fine roots functional traits were highest in the medium-sized individuals,and rhizosphere soil carbon,nitrogen,and phosphorus contents were also highest in medium-sized M.pauhoi.2)Variability coefficients of fine root traits such as specific root length,root volume density,fine root biomass,and rhizosphere soil fungal and actinomycete contents were relatively large among M.pauhoi individuals of different sizes,particularly pronounced in mediumsized individuals and relatively low in small-sized individuals.All individuals tend to adapt to environmental changes by adjusting traits such as root volume density,fine root biomass,rhizosphere soil fungal contents and nitrate nitrogen content.3)The fine roots at different individual sizes adopted different resource utilization strategies.Medium-sized M.pauhoi exhibited larger specific root length,root nitrogen content,and root phosphorus content,indicating a resource acquisition strategy to optimize nutrient acquisition capacity.Small-sized individuals with larger root tissue density adopted a resource conservation strategy to enhance their ability to cope with environmental stress,while large individuals exhibited a balanced strategy between above-ground and below-ground growth.4)Soil total carbon content,microbial biomass carbon content,actinomycete content,ammonium nitrogen content,acid phosphatase activity,and microbial biomass nitrogen content in the rhizosphere soil microenvironment were identified as the main factors influencing fine root functional traits of M.pauhoi.The relationship between fine root functional traits and rhizosphere microenvironment varied among individuals of different sizes.Fine roots of small-sized M.pauhoi individuals were mainly affected by rhizosphere soil nutrients,while those of medium-sized M.pauhoi individuals were primarily influenced by the content of actinomycete and acid phosphatase activity in the rhizosphere soil.Fine root traits of large-sized individuals were affected by both rhizosphere soil nutrients and soil microbial community structure,including bacteria and actinomycete content.The finding provide theoretical insights for implementing afforestation of M.pauhoi on a microtopographic scale,precisely developing artificial forest tending and thinning measures,and cultivating large-diameter timber plantations.
作者
刘瑶
钟全林
徐朝斌
程栋梁
郑跃芳
邹宇星
张雪
郑新杰
周云若
LIU Yao;ZHONG Quan-Lin;XU Chao-Bin;CHENG Dong-Liang;ZHENG Yue-Fang;ZOU Yu-Xing;ZHANG Xue;ZHENG Xin-Jie;ZHOU Yun-Ruo(College of Geographical Sciences,Fujian Normal University,Fuzhou 350007,China;State Key Laboratory Breeding Base of Humid Subtropical Mountain Ecology,Fujian Province Key Laboratory of Plant Ecophysiology,Fujian Normal University,Fuzhou 350007,China)
出处
《植物生态学报》
CAS
CSCD
北大核心
2024年第6期744-759,共16页
Chinese Journal of Plant Ecology
基金
国家自然科学基金(32371859、31971643和32071555)
中央财政林业科技推广示范项目(闽2023TG29)
福建省科技厅高校产学合作项目(2023N5006)
福建省林业局科技项目(2021FKJ29和2023FKJ29)。
关键词
细根功能性状
根际土壤
土壤微生物群落结构
土壤酶活性
林木大小
刨花楠人工林
fine root function trait
rhizosphere soil
soil microbial community structure
soil enzyme activity
tree size
Machilus pauhoi plantation
