添加酸雨酸度和硫氮比对麻栎林细根生长的影响  

Effects of Different Acidities and Sulfur to Nitrogen Ratios of Added Acid Rain on the Growth of Fine Roots of Quercus acutissima

作　　者：赵文瑞[1] 刘鑫[1] 张金池[1] 王玲[1] 谢德晋 袁颖丹[1] 王金平[1] 王鹰翔[1] 

机构地区：[1]南京林业大学江苏省水土保持与生态修复重点实验室南方现代林业协同创新中心,南京210037

出　　处：《林业科学》2017年第4期158-165,共8页Scientia Silvae Sinicae

基　　金：国家自然科学基金项目(31470709);国家科技计划项目(2015BAD07B0405);江苏省优势学科(PAPD)

摘　　要：【目的】探究野外林地环境下不同类型酸雨对麻栎细根的影响,为研究酸雨污染类型转变对林业生态系统的影响和林业经营管理及可持续发展提供理论依据。【方法】随机在麻栎林中距树干1.0 m处选取120个长2 m、宽0.6 m的样方,其0~20 cm表层土壤的pH为4.25,交换性Al3+和H+含量为4.90和0.30 cmol·kg^(-1)。按照摩尔物质量比配置5∶1、1∶1和1∶5共3种硫氮比酸溶液,均于野外用山间溪水稀释成pH为4.5、3.5和2.5共3种梯度的酸溶液,用来模拟不同类型酸雨。将南京地区2002—2013年月均降雨量的2/3设定为年总添加酸雨量,根据月均降雨量比例得出每月喷施量。2015年3月—2016年2月,将酸溶液每月分2次喷施于相应样方中(每次喷施一半,不遮挡自然降雨)。每3个月取1次样,每次共选取30个样方(每个样方在1次取样后将被废弃)。用土钻钻取0~20 cm土柱,挑出直径<2 mm的麻栎根,测定各项指标。【结果】在添加酸雨pH为4.5时,细根生物量增加、活根比例上升、长度密度增加、根尖数量增加、平均根径减小、周转速率加快;在添加酸雨pH小于4.5时,细根总生物量降低、活根比例下降、长度密度减小、根尖数量降低、平均根径增大、周转速率降低;酸雨pH和硫氮比对细根的影响存在显著交互效应,随着pH降低,不同硫氮比处理间差异逐渐减小;同酸度不同硫氮比酸处理下细根生物量、活根比例、根长密度、根尖密度、周转速率均表现为5∶1>1∶1>1∶5,平均根径表现为5∶1<1∶1<1∶5;细根总生物量、根长密度、根尖密度对酸雨响应强度表现为夏季>春季>秋季>冬季,细根平均根径对酸雨响应强度表现为冬季、春季>秋季、夏季,细根活根比例季节差异不明显。【结论】细根对酸雨的响应强度随季节的变化而变化,随着酸雨pH降低,酸雨对细根生长的影响表现为先促进后抑制,酸雨对细根生长的影响主要作用�[ Objective ] The effects of different types of acid rain on the fine roots of Quercus acutissima were studied to provide a theoretical basis for studying the impacts of the pollution by acid rain on forest ecosystem and forest management and sustainable development. [ Method ] A total of 120 sample plots in a size of 2 m by 0.6 m were selected randomly 1.0 m away from the trunks of Q. acutissima trees, the pH of the 0 - 20 cm surface soil was 4.25, exchangeable A13. and H＋ contents were 4.90 and O. 30 cmol. kg-1. Three types of acid solutions at 5： 1, 1 ： 1 , and 1：5 of sulfur to nitrogen ratios were prepared according to the molar mass ratio, and diluted into a gradient of three pH of 4.5, 3.5 and 2.5 in the field with the water from mountain stream, which will be used to simulate different types of acid rain. 2/3 of the monthly average rainfall in the 2002--2003 period in Nanjing was set as the total annual addition of acid rain, and then the monthly spraying amount of the acid solution was obtained according to the monthly rainfall ratio. From March 2015 to February 2016, the acid solutions were sprayed twice a month in the corresponding sample plots （half of the total each spray, not block the natural rainfall）. Soil samples were collected every three months, 30 sample plots were sampled each time （sample plots were discarded after sample collection）. Samples of 0 -20 cm soil column were taken with soil drill, and roots of Q. acutissima with diameters 〈 2 mm were picked out and measured for all traits. [ Result] When the pH of added acid rain was 4.5, the biomass of fine roots increased, the proportion of living roots increased, the length density increased, the number of root tips increased, the average root diameter decreased and the turnover rate accelerated. When the pH of acid rain was less than 4.5, the total biomass of fine root decreased, the proportion of living roots decreased, the length density decreased, the number of root tips decreased, the average root diameter increased, an

关 键 词：麻栎林 酸雨 硫氮比 pH 细根生长 

分 类 号：S719[农业科学—林学]