亚热带人工林不同植物生长型凋落叶溶解性有机质数量和光谱学特征  

Amounts and spectral characteristics of dissolved organic matter leached from leaf litters among different plant growth forms in subtropical plantations

作　　者：丁翊东 李素丽 张芸 徐佳文 吴盼盼 毛瑢 DING Yidong;LI Suli;ZHANG Yun;XU Jiawen;WU Panpan(MAO Rong Key Laboratory of National Forestry and Grassland Administration on Forest Ecosystem Protection and Restoration of Poyang Lake Watershed,College of Forestry,Jiangxi Agricultural University,Nanchang 330045,China)

机构地区：[1]江西农业大学林学院,国家林业和草原局鄱阳湖流域森林生态系统保护与修复实验室,南昌330045

出　　处：《生态学杂志》2023年第9期2081-2090,共10页Chinese Journal of Ecology

基　　金：国家自然科学基金项目(32060295和31800524);江西省“双千计划”项目(jxsq2018106044);江西省青年科学基金资助项目(20202BABL215017);江西省杰出青年基金项目(20212ACB215002)资助。

摘　　要：凋落叶淋溶过程产生的溶解性有机质(DOM)在森林土壤有机碳和养分循环中发挥着重要作用,然而亚热带不同植物生长型(阔叶、针叶和林下蕨类)淋溶产生的DOM数量、化学组成及结构等基本特征还不明确,尤其缺乏多树种的实验数据。基于此,本研究选取江西省亚热带人工林中常见的11种阔叶树、3种针叶树和4种林下蕨类植物的凋落叶为研究对象,通过室内淋溶试验比较不同植物生长型凋落叶源DOM数量和光谱学特征的差异,并分析DOM数量和光谱结构与凋落叶初始性质的相关性。结果表明:凋落叶淋溶产生的DOM数量和化学组成在植物生长型间存在显著差异,阔叶树凋落叶溶解性有机碳(DOC)和溶解性全氮(DTN)数量最多,而蕨类植物凋落叶的溶解性全磷(DTP)数量最高;阔叶树和蕨类植物凋落叶DOM有更高的SUVA254和SUVA280值以及更低的S275-295和SR值,意味着它们有更高的DOM芳香化程度和更大的分子质量;相关分析和多元线性回归分析结果显示,凋落叶初始元素含量、化学计量比及叶片物理性质(比叶面积、组织密度和饱和持水量)能够很好地解释不同生长型凋落叶溶出物数量和芳香结构的变异。综合研究结果,在亚热带低效林和纯针叶林补植阔叶树,促进DOM的输入及其组成多样性,是提升土壤碳库和林分生产力等生态服务功能的有效手段。Dissolved organic matter(DOM)leached from plant litter plays an essential role in carbon(C)and nutrient cycling in forest soils.However,the characteristics of leaf litter leachates(i.e.,amounts,chemical composition and structure)from different plant growth forms are still unclear,especially lacking of empirical evidence of multiple tree species.In this study,we collected leaf litters of 11 broadleaf tree species,3 coniferous tree species,and 4 fern species from subtropical plantations in Jiangxi Province.A laboratory leaching experiment was conducted to compare the difference in leaf litter-leached DOM parameters among plant growth forms.Furthermore,the correlation between DOM parameters and initial leaf litter properties was analyzed.The results showed that amounts and chemical composition of litter-leached DOM exhibited substantial variations among plant growth forms.Specifically,amounts of dissolved organic carbon(DOC)and total nitrogen(DTN)leached from leaf litter were greatest in broadleaf trees,but ferns had highest amounts of dissolved total phosphorus(DTP).Compared with coniferous trees,broadleaf trees and ferns had higher SUVA254 and SUVA280 values but lower S275-295 and SR values in litter leachates,indicating higher DOM aromaticity and molecular weight in litter leachates from broadleaf trees.Leaf carbon content,nutrient content,stoichiometric ratios,and physical traits(i.e.,specific leaf area,tissue density and waterholding capacity)would well explain the variations in production and aromatic degree of DOM of leaf litter from dif-ferent plant growth forms.Our results suggest that replanting broadleaf tree under low-efficiency and coniferous plantations would be an effective strategy to improve ecological services,such as soil carbon pool and forest productivity by promoting the amounts and diversity of DOM input to soils.

关 键 词：凋落物层 林下植被 芳香化程度 淋溶 紫外光谱 土壤碳库 

分 类 号：S714[农业科学—林学]