基于δ^(13)C估算水分利用效率的2种模型比较——以峨眉山雷洞坪植物为例  

Comparison of Two Models Estimating Water Use Efficiency Based onδ^(13)C:A Case Study of Plant Species in Leidongping,Emei Mountains of China

作　　者：陈淼 刘顺 许格希[1,2] 陈健 史作民[1,2,3] Chen Miao;Liu Shun;Xu Gexi;Chen Jian;Shi Zuomin(Key Laboratory of Forest Ecology and Environment of National Forestry and Grassland Administration,Ecology and Nature Conservation Institute,Chinese Academy of Forestry,Beijing 100091,China;Sichuan Miyaluo Forest Ecosystem National Observation and Research Station,Lixian County 623100,China;Co-Innovation Center for Sustainable Forestry in Southern China,Nanjing Forestry University,Nanjing 210037,China)

机构地区：[1]中国林业科学研究院森林生态环境与自然保护研究所,国家林业和草原局森林生态环境重点实验室,北京100091 [2]四川米亚罗森林生态系统国家定位观测研究站,理县623100 [3]南京林业大学南方现代林业协同创新中心,南京210037

出　　处：《陆地生态系统与保护学报》2024年第2期14-23,共10页Terrestrial Ecosystem and Conservation

基　　金：国家自然科学基金项目(32171506);中央级公益性科研院所基本科研业务费专项资金项目(CAFYBB2021ZA002-2,CAFYBB2022QC002)。

摘　　要：【目的】通过对基于碳稳定同位素值(δ^(13)C)估算水分利用效率(iWUE)的2种模型(是否考虑叶肉导度,gm)之间差异的研究,有助于进一步理解gm对植物iWUE的影响。【方法】选择峨眉山雷洞坪针阔混交林中不同生长型植物,采集了48个物种的117个叶片样品,通过测定其叶片δ^(13)C,对比了早期估算iWUE模型(iWUEsim模型,将gm看作无穷大)与包含gm效应的iWUE模型(iWUEmes模型)之间的iWUE差异(iWUE_(difference)),以及这种差异随植物生长型变化的趋势。【结果】结果显示,iWUEsim的平均值(42.23±1.33μmol·mol^(-1))显著高于iWUEmes的平均值(28.10±0.65μmol·mol^(-1)),高估比例为3.64%~72.11%(平均49.58%±1.30%)。不同生长型植物的iWUEsim均显著大于iWUEmes,其中草本植物高估比例3.64%~48.00%(平均29.20%±5.16%),灌木高估比例13.68%~67.73%(平均48.44%±1.83%),乔木高估比例32.04%~72.11%(平均54.08%±1.47%)。此外,叶片功能性状对iWUE_(difference)有显著影响,相比于叶片厚度、叶片干物质含量和单位质量叶片氮含量,单位面积叶片氮含量和比叶重是影响iWUE_(difference)变化的主要因素。【结论】将gm看作无穷大会造成对基于δ^(13)C估算的iWUE的高估,未来估算植物iWUE时应考虑gm的影响。【Objective】The study investigated the differences between two models(with or without considering leaf mesophyll conductance,gm)for estimating water used efficiency(iWUE)based on stable carbon isotope value(δ^(13)C),contributing to a better understanding of the impact of gm on plant iWUE.【Method】In this study,a total of 117 samples of 48 species were selected from different plant growth forms in the mixed coniferous broadleaved forest of Leidongping of Emei Mountains.The difference in iWUE(iWUE_(difference))between the early used iWUE model(iWUEsim model,assuming gm as infinity)and the newly proposed iWUE model with gm effect(iWUEmes model),and the trend of iWUE_(difference) with the growth forms of plants were examined through measuring theδ^(13)C of leaves.【Result】The results showed that the mean value of iWUEsim(42.23±1.33μmol·mol^(-1))was significantly higher than that of iWUEmes(28.10±0.65μmol·mol^(-1)),with an overestimated ratio of 3.64%~72.11%(mean of 49.58%±1.30%).The iWUEsim of different plant growth forms were significantly higher than the iWUEmes,with an overestimated ratio of 3.64%to 48.00%(mean of 29.20%±5.16%)for herbs,13.68%to 67.73%(mean of 48.44%±1.83%)for shrubs,and 32.04%to 72.11%(mean of 54.08%±1.47%)for trees.In addition,the leaf functional traits also had important effects on the iWUE_(difference).Leaf nitrogen content per unit area and leaf mass per area were the main factors influencing the variation of iWUE_(difference),compared with leaf thickness,leaf dry matter content,and leaf nitrogen content per unit mass.【Conclusion】Assuming gm as infinite will lead to an overestimation of iWUE based onδ^(13)C,and the effect of gm should be taken into account when estimating plant iWUE in the future.

关 键 词：内在水分利用效率 叶肉导度 碳稳定同位素 植物生长型 单位面积叶片氮含量 比叶重 

分 类 号：Q948[生物学—植物学]