植物生态学报 ›› 2016, Vol. 40 ›› Issue (9): 893-901.DOI: 10.17521/cjpe.2016.0163

所属专题: 青藏高原植物生态学:群落生态学

• 研究论文 • 上一篇    下一篇

高寒森林溪流对凋落叶分解过程中木质素降解的影响

岳楷1, 杨万勤1,2, 彭艳1, 黄春萍1,3, 张川1, 吴福忠1,2,*()   

  1. 1四川农业大学生态林业研究所, 林业生态工程省级重点实验室, 高山森林生态系统定位研究站, 成都 611130
    2长江上游生态安全协同创新中心, 成都 611130
    3四川师范大学生命科学学院 成都 610101
  • 收稿日期:2016-05-09 接受日期:2016-07-23 出版日期:2016-09-10 发布日期:2016-09-29
  • 通讯作者: 吴福忠
  • 基金资助:
    国家自然科学基金(31270498、31570445和31500358)和高等学校博士学科点专项科研基金(20135103110002)。

Effects of streams on lignin degradation during foliar litter decomposition in an alpine forest

Kai YUE1, Wan-Qin YANG1,2, Yan PENG1, Chun-Ping HUANG1,3, Chuan ZHANG1, Fu-Zhong WU1,2,*()   

  1. 1Long-term Research Station of Alpine Forest Ecosystems, Provincial Key Laboratory of Ecological Forestry Engineering, Institute of Ecology and Forestry, Sichuan Agricultural University, Chengdu 611130, China

    2Collaborative Innovation Center for Ecological Security in the Upper Reaches of the Yangtze River, Chengdu 611130 ,China
    and
    3College of Life Science, Sichuan Normal University, Chengdu 610101, China
  • Received:2016-05-09 Accepted:2016-07-23 Online:2016-09-10 Published:2016-09-29
  • Contact: Fu-Zhong WU

摘要:

溪流广泛分布于高寒森林地表, 凋落于其中的林木凋落物的分解是整个森林生态系统物质循环的重要环节, 水体流动过程中的冲刷和淋洗作用及其他独特的环境条件可能显著影响凋落物中木质素的降解。该研究采用凋落袋法对比研究了岷江上游高寒森林4种典型且初始质量差异显著的凋落叶, 即康定柳(Salix paraplesia)、高山杜鹃(Rhododendron lapponicum)、方枝柏(Sabina saltuaria)和四川红杉(Larix mastersiana), 在不同生境(林下、溪流和河岸带)下分解过程中木质素残留质量和浓度(质量百分率)的动态变化特征。经过两年的分解, 发现溪流显著促进了凋落叶中木质素的降解; 同一物种凋落叶在不同生境下木质素残留质量差异显著(p < 0.05), 整体表现为溪流<河岸带<林下; 在凋落叶分解的初期木质素有明显的降解, 其浓度表现为先降低后升高, 但不同物种之间存在显著(p < 0.05)的差异; 在整个分解过程中, 木质素残留质量总体呈现出了降低的趋势。此外, 生境类型、分解时期和区域性环境因子(温度、pH值和营养元素的有效性)能显著影响木质素的降解率。这些结果表明, 传统上认为木质素在凋落叶分解初期相对稳定的观点可能并不准确, 其浓度很可能是先下降后升高, 这也与有关木质素动态的最新研究结果相一致。另一方面, 在不同分解时期和不同生境下, 凋落叶木质素降解率表现出了显著差异, 表明区域性环境因子在凋落叶分解和木质素降解过程中具有重要的作用。

关键词: 碳循环, 林下, 溪流, 河岸带, 降解率, 物种, 环境因子

Abstract:

AimsStreams are widely distributed in alpine forests, and litter decomposition in which is an important component of material cycling across the forest landscape. The leaching and fragmenting effects as well as the unique environmental factors in streams may have significant impacts on lignin degradation during litter decomposition, but studies on this are lacking.
Methods Using litterbag methods, we investigated the dynamics of lignin mass remaining and concentration (percent litter mass, %) during the decomposition of four foliar litters, which varied significantly in the initial litter chemical traits, from the dominant species of Salix paraplesia, Rhododendron lapponicum, Sabina saltuaria, and Larix mastersiana under different habitats (forest floor, stream, and riparian zone) in the upper reaches of the Minjiang River.
Important findings After two year’s incubation, litter lignin mass remaining for a specific litter species varied significantly (p < 0.05) among habitats, with an order of stream < riparian zone < forest floor. Lignin was degraded substantially in the early stage of litter decomposition process, and the lignin concentration first decreased and then increased with the proceeding of litter decomposition, but varied significantly (p < 0.05) among different litter species. Lignin mass showed a general trend of decrease across the 2-year decomposition course. In addition, habitat type, decomposition period and microenvironmental factors (e.g., temperature, pH value and nutrient availability) showed substantial influences on lignin degradation rate. These results suggest that the traditional view that lignin was relatively recalcitrant with an increase of concentration in the early stage of litter decomposition is challenged, but the loss of lignin in the early phrase is in line with recent findings about the fate of lignin during litter decomposition. Moreover, the significant differences of lignin degradation rates among different decomposition period and habitat types indicated that local-scale environmental factors can play a significant role in litter decomposition and lignin degradation processes.

Key words: carbon cycling, forest floor, stream, riparian zone, degradation rate, species, environmental factor