林窗对川西亚高山6种植物凋落叶纤维素降解的影响  

Effects of forest gaps on cellulose degradation during foliar litter decomposition in a subalpine forest of western Sichuan

作　　者：杜婷 刘一霖 杨玉婷 张玉[1] 游成铭 张丽[1] 谭波[1] 徐振锋[1] 李晗[1] DU Ting;LIU Yilin;YANG Yuting;ZHANG Yu;YOU Chengming;ZHANG Li;TAN Bo;XU Zhenfeng;LI Han(Forestry Ecological Engineering in the Upper Reaches of the Yangtze River Key Laboratory of Sichuan Province,National Forestry and Grassland Administration Key Laboratory of Forest Resources Conservation and Ecological Safety on the Upper Reaches of the Yangtze River,Long-term Research Station of Alpine Forest Ecosystems,Institute of Ecology&Forest,Sichuan Agricultural University,Chengdu 611130,China;Da'an Bureau of Natural Resources,Zigong 611130,China)

机构地区：[1]四川农业大学生态林业研究所,长江上游林业生态工程四川省重点实验室,长江上游森林资源保育与生态安全国家林业和草原局重点实验室,高山森林生态定位研究站,成都611130 [2]四川省自贡市大安区自然资源局,自贡643010

出　　处：《应用与环境生物学报》2021年第3期617-624,共8页Chinese Journal of Applied and Environmental Biology

基　　金：国家自然科学基金项目(31901295,32071745,31870602);国家重点研发计划项目(2017YFC0505003,2017YFC0503906);四川省杰出青年科技人才计划项目(2020JDJQ0052);四川省应用基础研究项目(2021YJ0340);四川农业大学科研兴趣培养项目(2020227,2021253)资助。

摘　　要：凋落物纤维素降解是森林生态系统碳循环的关键过程,其可能受到林窗直接或间接的影响.采用凋落物分解袋法,通过3年连续监测,研究川西亚高山6种常见木本植物凋落叶(岷江冷杉、红桦、四川红杉、方枝柏、康定柳和高山杜鹃)在不同林冠环境下(林窗中心、林缘林窗、扩展林窗和郁闭林下)冬季和生长季纤维素降解特征.结果显示:川西亚高山6种凋落叶分解过程中纤维素含量和残留率均呈现下降趋势,分解3年后纤维素含量为5.5%-12.1%且残留率下降至23.1%-44.6%.林窗中心处整体上具有较低的凋落叶纤维素含量和残留率,但这种差异性在分解3年后消失.相关性分析表明凋落叶纤维素含量和残留率与均温、初始纤维素、木质素含量和C/N值呈显著负相关,与冻融循环和初始有机溶性组分含量呈显著正相关.表明林窗的形成通过提供较高的温度或减少冻融循环的发生促进凋落叶纤维素的降解,但这种差异随着分解进程逐渐减弱,且受到凋落叶初始质量所代表的物种差异的影响.本研究表明林窗通过改变林内微环境促进凋落叶纤维素早期的降解,上述结果有助于进一步认识林窗在亚高山森林生态系统物质循环中的生态作用和意义.Litter decomposition is a key process in material cycling and soil fertility self-sustainment in forests.As the most abundant polymer carbon source in litter,cellulose plays a crucial role in the entire decomposition process.To further understand the material cycling process in subalpine forests of western Sichuan,we conducted a study using the litterbag method.We monitored cellulose concentration and the remaining cellulose in foliar litter in winter and growing seasons from the gap center,canopy gap,expanded gap,and closed canopy for 3 years.The results revealed that the litter cellulose concentration and remaining cellulose decreased significantly across the 3 years of decomposition,decreasing to 5.5%-12.1%and 23.1%-44.6%,respectively.Although a small amount of cellulose remained in the gap center,this disappeared by the end of the third year.Litter cellulose was significantly negatively correlated with average temperature,initial cellulose,lignin content,and C/N ratio but was significantly positively correlated with freeze-thaw cycles and initial organic soluble extractables.This suggests that the formation of forest gaps promoted cellulose degradation by providing high temperatures and reducing the number of freeze-thaw cycles.Our results indicated that forest gaps may promote cellulose degradation in the early decomposition of fresh litter by changing local-scale environmental factors.This enhances our understanding of the ecological role of forest gaps in material cycling in subalpine forest ecosystems.

关 键 词：纤维素 林窗 凋落叶分解 冻融循环 亚高山森林 

分 类 号：S714[农业科学—林学]