中亚热带喀斯特森林不同演替阶段树种水力调节策略差异  

Hydraulic regulation strategies of karst forest species exhibit variation across different successional stages in the mid-subtropical zone

作　　者：廖苏慧 倪隆康 秦佳双 谭羽 顾大形[1] LIAO Su-Hui;NI Long-Kang;QIN Jia-Shuang;TAN Yu;GU Da-Xing(Guangxi Key Laboratory of Plant Conservation and Restoration Ecology in Karst Terrain,Guangxi Institute of Botany,Guangxi Zhuangzu Autonomous Region and Chinese Academy of Sciences,Guangxi Guilin Urban Ecosystem National Observation and Research Station,Guilin,Guangxi 541006,China)

机构地区：[1]广西喀斯特植物保育与恢复生态学重点实验室,广西壮族自治区中国科学院广西植物研究所,广西桂林城市生态系统国家定位观测研究站,广西桂林541006

出　　处：《植物生态学报》2024年第9期1223-1231,共9页Chinese Journal of Plant Ecology

基　　金：国家自然科学基金(32060243,41830648)

摘　　要：喀斯特地区由于岩石大面积裸露、土层浅薄,地表极易失水,因此面临着抗干旱能力弱、演替进程缓慢等问题。探究中亚热带喀斯特森林不同演替阶段树种水力调节策略的变化,了解演替背后的干旱适应机制,能够为植被恢复和重建提供理论依据。该研究以喀斯特地区演替早、中和后期森林群落中的优势种为研究对象,测量并计算了茎和叶栓塞脆弱性(P_(50S)和P_(50L))、脆弱性分割(P_(50L-S))、茎和叶比导率(K_(S)和K_(L))、叶水力安全边界(HSML)等水力性状,以及边材密度、胡伯尔值和比叶面积(SLA)等水力相关指标。结果表明:(1)该研究在物种间和群落间均未发现水力安全与效率的权衡,P50S、KS和KL均随正向演替而减小。(2)所有树种均存在正向脆弱性分割,变化范围为0.53-6.59 MPa,演替早期显著大于中期和后期,且分割主要由P_(50S)决定。(3)演替早期植物拥有较大的栓塞抗性和K_(S)、K_(L),以提高水分运输和抵抗干旱的能力,后期形成较大的SLA以增加对光资源的竞争。该研究揭示了喀斯特森林植物随着演替发展过程,水力调节策略由以提高水力效率与安全的策略向增加对光合碳投资的策略转变的变化规律,为阐明喀斯特森林群落演替过程中的植物干旱适应机制提供理论依据。Aims The karst region encounters challenges such as low resistance to drought and delayed succession due to extensively exposed rocks and shallow soil layers,rendering the surface susceptible to dehydration.The study aims to investigate changes in hydraulic regulation strategies during different successional stages of species of subtropical karst forests.This exploration seeks to understand the mechanisms for adapting to drought following succession,and to establish a theoretical basis for vegetation restoration and reconstruction.Methods The study centered on dominant species in forest communities along the early,middle,and late stages of succession in karst areas.Various hydraulic traits including the vulnerability of embolism in stems and leaves(P_(50S)and P_(50L)),the vulnerability segmentation(P_(50L-S)),the specific conductivity of stems and leaves(K_(S)and K_(L)),the hydraulic safety margin of leaf(HSML),density of sapwood,the Huber value,and the specific leaf area(SLA)were investigated.Important findings(1)No trade-off was found between hydraulic safety and efficiency at either species or community level;P_(50S),K_(S),and K_(L)all decreased along the succession.(2)All species exhibited positive vulnerability segmentation,ranging from 0.53 to 6.59 MPa,and the vulnerability segmentation during early succession significantly exceeded those in the middle and late stages of succession.Furthermore,P_(50S)was identified as the primary determinant of the vulnerability segmentation.(3)The plants at early successional stage exhibited higher resistance to embolism,K_(S),and K_(L),which enhance the abilities of water transport and drought resistance.Conversely,in the later stage,plants showed larger SLA to improve competition for light resources.Our study reveals the patterns of adjustment of hydraulic regulation strategies,shifting from strategies aimed at improving hydraulic efficiency and safety to strategies aimed at increasing investment in photosynthetic carbon during the succession process of karst forest plan

关 键 词：脆弱性分割 水力性状 权衡 群落演替 喀斯特森林 

分 类 号：S718.5[农业科学—林学]