生态环境学报2025，Vol.34Issue(10)：1547-1557,11.DOI:10.16258/j.cnki.1674-5906.2025.10.005
干旱胁迫对5种不同根型树种幼苗干物质分配和根系形态的影响
Effects of Drought Stress on Dry Matter Distribution and Root Morphology in Seedlings of Five Tree Species with Varying Root Types
摘要
Abstract
In recent years,seasonal droughts have increasingly impacted subtropical regions,highlighting the potential significance of root morphological traits in shaping the drought resistance strategies of trees.To elucidate the adaptive mechanisms of tree species with varying root architectures in response to drought stress,this study focused on the seedlings of five subtropical species:the deep-rooted Camphora officinarum,Quercus variabilis,and Quercus glauca,and the shallow-rooted Cunninghamia lanceolata and Phyllostachys edulis.A 45-day drought stress was imposed using a natural water loss method to investigate responses in biomass allocation,organ water dynamics,and root morphological plasticity during the seedling stage.The results indicated that:1)deep-rooted tree seedlings significantly enhanced drought resistance by optimizing root morphology and redistributing dry matter.Specifically,the root biomass and fine root proportion of Camphora officinarum increased by 28.7％and 44.3％(p<0.05)from the onset of the experiment under short-term drought conditions,with root length and tip numbers continuing to expand throughout the drought period,thereby maintaining water homeostasis in the stems and leaves.The root/shoot ratio and fine root proportion of Quercus variabilis increased by 20.4％and 13.3％(p<0.05),respectively,with a notable increase in root diameter following prolonged drought exposure.The leaf biomass ratio of Quercus glauca increased by 44.4％(p<0.05)during the later stages of drought stress,although its limited root plasticity restricted its adaptation to only medium-term drought.2)In contrast,shallow-rooted tree seedlings predominantly rely on aboveground homeostatic mechanisms,with drought stress leading to root decline,thereby compromisings their drought resistance.The root biomass,root/shoot ratio,and overall water content of Cunninghamia lanceolata decreased by 22.0％,29.0％,and 62.9％(p<0.05),respectively.Phyllostachys edulis mitigated drought effects through short-term water storage in stems;however,prolonged stress resulted in the continued deterioration of root traits,with a 36.4％reduction in the root biomass ratio,impairing survival under extended drought conditions.3)Deep-rooted species effectively acquired resources through synergistic enhancements in root morphology and biomass allocation,whereas shallow-rooted species exhibited diminished absorption capacity owing to root shrinkage.In conclusion,deep-rooted species have adapted to prolonged drought conditions through active morphological plasticity and optimization of dry matter allocation within their root systems during the seedling stage.Conversely,shallow-rooted species adopt conservative aboveground homeostatic strategies that limit their ability to balance immediate survival and long-term drought resistance.Moreover,the drought resistance conferred by the root system depends not only on the depth of root architecture but also on the synergistic optimization of biomass distribution strategies and the functional plasticity of various organs.关键词
干旱/生物量/干物质分配/含水率/根系可塑性Key words
drought/biomass/dry matter partitioning/water content/root plasticity分类
农业科技引用本文复制引用
杨佳伟,辜忠春,胡琦,戴薛,王晓荣,兰竹,何玲,刘学全..干旱胁迫对5种不同根型树种幼苗干物质分配和根系形态的影响[J].生态环境学报,2025,34(10):1547-1557,11.基金项目
湖北省自然科学基金计划项目(2023AFB1094) （2023AFB1094）
湖北省林科院自主立项项目(ZZLX202410) （ZZLX202410）
