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植物研究 ›› 2017, Vol. 37 ›› Issue (6): 848-854.doi: 10.7525/j.issn.1673-5102.2017.06.007

• 研究报告 • 上一篇    下一篇

氮添加对温带森林细根长期分解的影响

李媛媛, 王正文, 孙涛   

  1. 中国科学院沈阳应用生态研究所, 沈阳 110016
  • 收稿日期:2017-04-07 出版日期:2017-11-15 发布日期:2017-11-25
  • 通讯作者: 孙涛 E-mail:sunt@iae.ac.cn
  • 作者简介:李媛媛(1976-),女,助理研究员,主要从事生物地球化学循环研究。
  • 基金资助:
    国家自然科学基金资助项目(31500361)

Response of Fine Root Decomposition to Long-term Nitrogen Addition in the Temperate Forest

LI Yuan-Yuan, WANG Zheng-Wen, SUN Tao   

  1. Institute of Applied Ecology, Chinese Academy of Sciences, Shenyang 110016
  • Received:2017-04-07 Online:2017-11-15 Published:2017-11-25
  • Supported by:
    Natural Science Foundation of China(31500361)

摘要: 细根分解是森林生态系统碳循环的重要过程之一,其分解速率受到大气氮沉降增加的潜在影响。利用长期模拟氮沉降样地(2009年至今),采用凋落物分解袋方法,研究了氮添加对温带常见的5个森林树种长期细根分解的影响。结果表明:细根分解呈现先快后慢的趋势,在分解第516天质量损失达30%~50%,之后质量残留率变化较为平缓。总体上,渐近线分解模型可以更准确的反应各处理细根分解速率。氮添加对细根分解具有阶段性影响,分解前期促进细根分解,分解后期抑制分解。在细根分解后期氮添加减缓分解速率,一方面是因为木质素等较难分解的物质所占比例升高所带来的直接影响,另一方面,是因为氮添加改变了微生物活动所带来的间接影响。

关键词: 氮沉降, 温带森林, 细根, 凋落物分解

Abstract: As one of the important processes of carbon(C) cycling in forest ecosystems, fine root litter decomposition is potentially affected by elevated atmospheric nitrogen(N) deposition. Since 2009, a five-year fine root decomposition experiment was conducted in long-term N addition plots using a litter bag method. The decomposition rates of fine roots were higher at the early stage and slower at the later stage of decomposition. Mass loss of fine roots was up to 30% 50% in the 516th day of decomposition, and the variation in the remaining mass was relatively stable in the later stage. In general, the asymptotic decomposition models provided the best prediction for fine root decomposition of the five species. Nitrogen addition had a stage-specific effect on fine root decomposition, which was promotion for the early stage while inhibition for the later. At the later stage, N addition slowed down decomposition rate of fine roots, which was partly due to the direct effect of increasing proportion of recalcitrant compounds, such as lignin, and the indirect effect of alteration in microbial activity was affected by N addition.

Key words: nitrogen deposition, temperate forest, fine root, litter decomposition

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