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应用生态学报 ›› 2021, Vol. 32 ›› Issue (9): 3119-3126.doi: 10.13287/j.1001-9332.202109.002

• 研究论文 • 上一篇    下一篇

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

刘洋1,2, 彭云峰2*, 门明新1, 彭正萍1, 杨元合2,3   

  1. 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
  • 收稿日期:2021-02-20 接受日期:2021-06-22 出版日期:2021-09-15 发布日期:2022-03-15
  • 通讯作者: * E-mail: pengyf@ibcas.ac.cn
  • 作者简介:刘 洋, 男, 1988年生, 博士研究生。主要从事草地土壤碳循环研究。E-mail: 13994206486@163.com
  • 基金资助:
    国家自然科学基金项目(31770521,31400417)和第二次青藏高原综合科学考察研究项目(2019QZKK0302)资助

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

LIU Yang1,2, PENG Yun-feng2*, MEN Ming-xin1, PENG Zheng-ping1, YANG Yuan-he2,3   

  1. 1College of Resources and Environmental Science/Hebei Province Key Laboratory for Farmland Eco-Environment, Agricultural University of Hebei, Baoding 071000, Hebei, China;
    2State Key Laboratory of Vegetation and Environmental Change, Institute of Botany, Chinese Academy of Sciences, Beijing 100093, China;
    3University of Chinese Academy of Sciences, Beijing 100049, China
  • Received:2021-02-20 Accepted:2021-06-22 Online:2021-09-15 Published:2022-03-15
  • Contact: * E-mail: pengyf@ibcas.ac.cn
  • Supported by:
    National Natural Science Foundation of China (31770521, 31400417) and the Second Tibetan Plateau Scientific Expedition and Research (STEP) Program (2019QZKK0302).

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。

关键词: 根系生产, 根系周转, 氮沉降, 草地

Abstract: 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.

Key words: root production, root turnover, nitrogen deposition, grassland