植物生态学报 ›› 2008, Vol. 32 ›› Issue (3): 622-631.DOI: 10.3773/j.issn.1005-264x.2008.03.011

• 论文 • 上一篇    下一篇

西双版纳热带雨林凋落叶分解的生态过程.Ⅲ.酶活性动态

张瑞清1,2(), 孙振钧1,*(), 王冲1, 袁堂玉2   

  1. 1 中国农业大学资源与环境学院,北京 100094
    2 山东省烟台市农业科学研究院,山东烟台 265500
  • 收稿日期:2006-04-03 接受日期:2006-06-26 出版日期:2008-04-03 发布日期:2008-05-30
  • 通讯作者: 孙振钧
  • 作者简介:*E-mail:sun108@cau.edu.Cn;
    E-mail:zrqnancy@sohu.com
  • 基金资助:
    国家科技部“973”重大基础研究前期研究专项(2002CCA00800)

ECOLOGICAL PROCESS OF LEAF LITTER DECOMPOSITION IN TROPICAL RAINFOREST IN XISHUANGBANNA, SW CHINA. Ⅲ. ENZYME DYNAMICS

ZHANG Rui-Qing1,2(), SUN Zhen-Jun1,*(), WANG Chong1, YUAN Tang-Yu2   

  1. 1College of Resources and Environmental Sciences, China Agricultural University, Beijing 100094, China
    2Yantai Academy of Agricultural Sciences, Yantai, Shandong 265500, China
  • Received:2006-04-03 Accepted:2006-06-26 Online:2008-04-03 Published:2008-05-30
  • Contact: SUN Zhen-Jun

摘要:

该文通过野外试验和室内模拟相结合,系统研究了西双版纳热带雨林生态系统混合凋落叶分解过程中的酶活性动态。野外试验采用网袋法(1 mm和100 μm网眼)限制土壤动物的出入,室内模拟试验采用灭菌-接种法控制生物组成,从而研究不同生物组成或食物链结构条件下,凋落叶分解过程中的酶活性变化,以及酶活性与分解进程之间的动态响应。研究结果表明,转化酶和淀粉酶在有机残体的最初分解阶段发挥重要作用,参与易分解成分的转化和分解,这些酶与凋落叶分解进程之间存在显著的负相关性,且参与分解的生物组成越简单(缩短食物链),这些酶活性越高,是微生物在分解初期对底物加以利用的关键酶类;C x酶、β-葡萄糖苷酶、木聚糖酶活性均在分解中期达到高峰,多酚氧化酶在分解后期迅速上升,对凋落叶中、后期木质素的分解起到关键性的作用,这些酶与凋落叶分解进程之间存在显著的正相关性,且参与分解的生物组成越复杂(延长食物链),这些酶活性越高,是微生物在分解后期对底物进一步利用的关键酶类;与C循环有关的酶类都可以作为有机物质分解进程的重要指标,与分解进程之间存在一定的动态响应,有机残体的分解过程实质上是一个酶解过程。

关键词: 西双版纳, 热带雨林, 凋落叶, 分解, 酶活性

Abstract:

Aims We tested the dynamics of nine enzymes during leaf litter decomposition in Xishuangbanna tropical rainforest both in the field and laboratory to explore the response of enzyme dynamics to decomposition under different food-web structures.

Methods We used coarse and fine (1 mm and 100 μm mesh size, respectively) litterbags in the field to create different food-web structures during litter decomposition. Most soil macrofauna such as nematodes could access only the coarse mesh litterbags, leaving only microbiota such as mites in the fine mesh litterbags. In the laboratory, sterilization and inoculation were adopted to investigate different enzyme dynamics with nematodes or only microbiota participating in litter decomposition.

Important findings Invertase and amylase increased more for shorter food webs at early stages of decomposition, while activities of endocellulase, β-glucosidase, xylanase and polyphenoloxydase increased to their maxima at later stages, but greater increase occurred with extended food webs. Invertase and amylase had negative and endocellulase, β-glucosidase, xylanase and polyphenoloxydase had positive relationships with litter decomposition (mass loss). Activities of enzymes responded to the process of litter decomposition. Invertase and amylase played key roles for microbiota utilizing the substrates at early stages of decomposition, while endocellulase, β-glucosidase, xylanase and polyphenoloxydase worked on the further decay of recalcitrant compounds at later stages. All enzymes related to C decay acted as effective indicators of litter decomposition. The decomposition of plant organic matter was essentially an enzymatic process.

Key words: Xishuangbanna, tropical rainforest, leaf litter, decomposition, enzyme activity