首页|基于δ13C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

基于δ13C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

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[目的]通过对基于碳稳定同位素值(δ13C)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δ13C,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(iWUEdifference),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±1.33 μmol·mol-1)显著高于iWUEmes的平均值(28.10±0.65 μmol·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iWUEdifference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iWUEdifference变化的主要因素.[结论]将gm看作无穷大会造成对基于δ13C估算的iWUE的高估,未来估算植物iWUE时应考虑gm的影响.
Comparison of Two Models Estimating Water Use Efficiency Based on δ13C:A Case Study of Plant Species in Leidongping,Emei Mountains of China
[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(δ13C),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(iWUEdifference)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 iWUEdifference with the growth forms of plants were examined through measuring the δ13C of leaves.[Result]The results showed that the mean value of iWUEsim(42.23±1.33 μmol·mol-1)was significantly higher than that of iWUEmes(28.10±0.65 μmol·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 iWUEdifference.Leaf nitrogen content per unit area and leaf mass per area were the main factors influencing the variation of iWUEdifference,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 on δ13C,and the effect of gm should be taken into account when estimating plant iWUE in the future.

intrinsic water-use efficiencymesophyll conductancestable carbon isotopeplant growth formleaf nitrogen content per unit arealeaf mass per area

陈淼、刘顺、许格希、陈健、史作民

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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

四川米亚罗森林生态系统国家定位观测研究站,理县 623100

南京林业大学南方现代林业协同创新中心,南京 210037

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

国家自然科学基金项目中央级公益性科研院所基本科研业务费专项资金项目中央级公益性科研院所基本科研业务费专项资金项目

32171506CAFYBB2021ZA002-2CAFYBB2022QC002

2024

10.12356/j.2096-8884.2024-0003

陆地生态系统与保护学报

陆地生态系统与保护学报

ISSN：
年,卷(期)：2024.4(2)