青藏高原高寒草原根系动态对氮添加的响应及其调控因素  

Response of root dynamics to nitrogen addition and the influencing factors in a Tibetan alpine steppe,China

作　　者：刘洋 彭云峰 门明新 彭正萍 杨元合[2,3] LIU Yang;PENG Yun-feng;MEN Ming-xin;PENG Zheng-ping;YANG Yuan-he(College of Resources and Environmental Science/Hebei Prowince Key Laboratory for Farmland Eco-Enwironment,Agricultural University of Hebei,Baoding 071000,Hebei,China;State Key Laboratory of Vegetation and Environmental Change,Institute of Botany,Chinese Academyof Sciences,Beijing 100093,China;University of Chinese Academy of Sciences,Beijing 100049,China)

机构地区：[1]河北农业大学资源与环境科学学院/河北省农田生态环境重点实验室,河北保定071000 [2]中国科学院植物研究所植被与环境变化国家重点实验室,北京100093 [3]中国科学院大学,北京100049

出　　处：《应用生态学报》2021年第9期3119-3126,共8页Chinese Journal of Applied Ecology

基　　金：国家自然科学基金项目(31770521,31400417);第二次青藏高原综合科学考察研究项目(2019QZKK0302)资助。

摘　　要：本研究于2015—2016年进行野外控制试验,分析了不同施氮(N)水平(0、1、2、4、8、16 g N·m^(-2)·a^(-1))对青藏高原高寒草原根系生产、周转速率和现存量的影响及其调控因素。结果表明:随着施N量的增加,根系生产量和现存量呈线性或指数下降的趋势。与对照相比,16 g N·m^(-2)·a^(-1)处理根系生产量和现存量2年平均下降43.0%和45.7%。根系周转速率呈先上升后下降的趋势,2015年和2016年分别在2和4 g N·m^(-2)·a^(-1)处理达到峰值。线性混合模型结果显示,根系淀粉含量是调控根系生产量和周转速率的主要因素,分别解释二者变异的21.7%和25.4%;而根系现存量则受根系蛋白含量的影响,其解释率为20.8%。N富集对根系生产和现存量表现出抑制作用,低N促进而高N抑制根系周转速率,根系碳氮代谢指标是调控根系动态对N添加响应的主要因素。A field manipulative experiment was carried out during 2015 and 2016 to examine the changes and influencing factors of root production,turnover rate,and standing crop under different nitrogen(N)addition levels,i.e.,0,1,2,4,8 and 16 g N·m^(-2)·a^(-1),in a Tibetan alpine steppe.The results showed that root production and standing crop decreased linearly or exponentially with increasing N addition rates.Compared with control,16 g N·m^(-2)·a^(-1) significantly reduced the two-year average root production and standing crop by 43.0%and 45.7%,respectively.Root turnover rate increased first and then decreased along the N addition gradient,with the maximum appearing under 2 and 4 g N·m^(-2)·a^(-1) treatments for 2015 and 2016,respectively.Results from linear mixed-effects models showed that root starch content was the main factor modulating the N-induced changes in root production and turnover rate,explaining 21.7%and 25.4%of their variations.Root protein content mainly contributed to the variations in standing crop,with an explanation of 20.8%of its variance.Overall,N addition had negative effect on root production and standing crop,and low N promoted while high N inhibited root turnover rate.Root metabolic parameters were the main factors modulating the N-induced changes in root dynamics.

关 键 词：根系生产 根系周转 氮沉降 草地 

分 类 号：S812[农业科学—草业科学]