南亚热带两种优势树种叶凋落物分解对模拟酸雨的响应  

Response of leaf litter decomposition of two dominant trees to simulated acid rain in southern China

作　　者：梁国华[1,2] 李荣华[1,2] 丘清燕[1,2] 陈小梅[1,2] 周国逸[1] 褚国伟[1] 张德强[1] 

机构地区：[1]中国科学院华南植物园,广州510650 [2]中国科学院大学,北京100049

出　　处：《生态学报》2014年第20期5728-5735,共8页Acta Ecologica Sinica

基　　金：国家重点基础研究发展计划(973)项目(2009CB421101);中国科学院战略性先导科技专项(XDA05050205);鼎湖山站联合资助

摘　　要：通过对模拟酸雨处理下鼎湖山季风常绿阔叶林优势树种锥栗(Castanopsis chinensis)和木荷(Schima superba)叶凋落物分解的研究,试图探讨南亚热带区域日益严重的酸雨对森林凋落物分解的影响规律以及可能的机制。试验应用分解袋法进行,并设计4个模拟酸雨强度处理:CK(p H值4.5左右的天然湖水)、T1(p H值4.0)、T2(p H值3.5)和T3(p H值3.0)。21个月的分解结果表明,模拟酸雨抑制了两种优势树种叶凋落物的分解。CK、T1、T2和T3 4个处理下的分解速率常数k值分别为:锥栗(1.18、0.93、0.94和0.86)和木荷(1.10、0.97、0.88和0.94),与CK相比,k值在T1、T2和T3均有下降的趋势。同时,模拟酸雨下两种优势树种叶凋落物的质量残留率均为:T3>T2>T1>CK。酸雨对凋落物分解的抑制作用可能与酸雨胁迫下土壤酸化从而导致土壤微生物活性下降有关。Litter decomposition plays an important role in the maintainance of forest structure and function,and therefore,its response to environmental changes is an increasing concern. Acid rain has become a serious environmental threat in southern China in recent years. However,the response of litter decomposition to acid rain in forests of this region is poorly understood. Here,response of leaf litter decomposition for two dominant trees（ Castanopsis chinensis and Schima superba） to simulated acid rain（ SAR） was investigated in a monsoon evergreen broad-leaved forest at the Dinghushan Nature Reserve.Litter decomposition was measured by the litter bag method following four SAR treatments（ CK,the local lake water,p H4. 5; T1,water p H 4.0; T2,water p H 3.5; and T3,water p H 3.0）. SAR treatments were initiated in June 2009 and were sprayed twice a month during the study period. Results indicated that soil p H values among treatments were not significantly different in June 2010（ after SAR treatments for 13 months）. However,after SAR treatments for 25 months（ in June2011）,the soil p H values generally decreased with the decrease of treatment p H values with mean soil p H value in the T3 treatment significantly lower than that in the CK treatment,which indicated the aggravation of soil acidification. Meanwhile,during the decomposition period of 21 months（ from October 2009 to July 2011）,litter decomposition of two dominant trees has been slowed down under the stress of SAR treatments with decomposition rates of 1.18,0.93,0.94 and 0.86 in the CK,T1,T2 and T3 treatments,respectively in Castanopsis chinensis and 1. 10,0. 97,0. 88 and 0. 94,respectively in Schima superba. Mass remaining of leaf litter was also depressed after exposure to SAR treatments with CK 〈T1 〈T2 〈T3 for both tree species. In addition,similar to the gradual process of soil acidification under SAR treatments,the restrained effects of SAR treatments on the leaf litter decomposition had also been strengthened over time with signif

关 键 词：模拟酸雨 凋落物分解 季风常绿阔叶林 土壤pH值 土壤微生物活性 

分 类 号：S714[农业科学—林学] X517[环境科学与工程—环境工程]