Page 6 - 《广西植物》2024年第7期
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LI Xun ꎬ ZHANG Yan ꎬ SONG Simeng ꎬ ZHOU Yang ꎬ ZHANG Jian
( 1. Research Center for Ecological Restoration and Characteristic Industry Cultivation in Hengduan Mountains Regionꎬ Sichuan Minzu Collegeꎬ
Kangding 626001ꎬ Sichuanꎬ Chinaꎻ 2. Key Laboratory of Forestry Ecological Engineering in Sichuanꎬ Collaborative Innovation Center
of Ecological Security in the Upper Reaches of Yangtze Riverꎬ Institute of Foresty Ecologicalꎬ College
of Forestryꎬ Sichuan Agricultural Universityꎬ Chengdu 611130ꎬ China)
Abstract: In order to adjust the structure of inefficient Pinus massoniana (P) forest and explore the dynamic changes
for dissolved organic carbon (DOC) during the mixed decomposition process of P. massoniana and native broad ̄leaved
tree species. Our research focuses on the leaf litter of P. massonianaꎬ Cinnamomum camphora (C) and Toona sinensis
(T)ꎬ and combine them into the 15 treatments (3 single tree treatments + 12 mixed treatments) according to different
tree species combinations and mass proportionsꎬ and then conducted field decomposition experiments to further explore
the optimal tree species combination and the proportion of mixed planting for DOC release. The results were as follows:
(1) DOC content of Pinus massoniana and most of mixed treatments (except for PT64) significantly increased during
the early stages of decomposition (0-6 months)ꎬ leading to carbon enrichment. The DOC content of leaf litter decreased
with the extension of decomposition timeꎬ and also exhibited carbon enrichment in small degree during the middle to late
stages of decomposition (12-18 months) or the late stages of decomposition (18-24 months). Mixed leaf litter showed
that the higher the proportion of broad ̄leavedꎬ the lower the DOC content in the later stage. (2) The antagonistic effect
of DOC release rate in the early stage of decomposition (0-6 months) was strong (58.33%)ꎬ and only 8.33% (1/ 12) of
mixed treatments showed the synergistic effect. Its synergistic effect gradually strengthened (91. 67%) after 6 - 18
monthsꎬ but the synergistic effect of leaf litter (66.67%) during the late stage of decomposition weakened (18- 24
months). Among all mixed treatmentsꎬ PT64 exhibited synergistic effects throughout the entire decomposition stageꎬ
followed by PT73ꎬ PCT622 and PCT613(3/ 4). (3) Partial least ̄squares (PLS) regression showed that N contentꎬ P
contentꎬ lignin contentꎬ condensed tannin contentꎬ C/ Nꎬ C/ Pꎬ lignin/ Nꎬ and lignin/ P were important quality factors
affecting the release of DOC from litter in this study area. Overallꎬ the DOC release from mixed Pinus massoniana and
broad ̄leaved leaf litter is affected by tree speciesꎬ mixed proportion and decomposition time. Compared to other mixed
treatmentsꎬ the proportion of broad ̄leaved greater is than or equal to 30. 00% and the mixed leaf litter treatments
including Toona sinensis (PT64ꎬ PT73ꎬ PCT622 and PCT613) show strong synergistic effects for DOC release.
Key words: Pinus massonianaꎬ native broad ̄leaved tree speciesꎬ mixed leaf litterꎬ dissolved organic carbonꎬ synergistic
effectsꎬ antagonistic effects
凋 落 叶 源 可 溶 性 有 机 碳 ( dissolved organic 针叶树种(林开敏等ꎬ 2010ꎻ Joly et al.ꎬ 2016ꎻ Wu
carbonꎬ DOC)是森林物质循环的重要组分和土壤 et al.ꎬ 2021)ꎬ如阔叶树凋落叶可释放高浓度的可
活性碳库的重要来源(Bradford et al.ꎬ 2016)ꎬ对维 溶性氮(N)、磷( P) 等养分ꎬ这些元素决定了阔叶
持森林生态系统稳定性以及林地有机物生产具有 凋落叶淋溶液中的 DOC 与可溶性养分的比例较高
重要意义( 李吉玫等ꎬ 2017ꎻ 万雪冰等ꎬ 2019)ꎮ (Mastny ' et al.ꎬ 2018)ꎮ 另一方面ꎬ凋落叶的结构
研究凋落叶分解过程释放的 DOC 特性对于维持森 (如表面是否具有蜡质和绒毛) 以及持水能力也是
林生态系统稳定性和准确科学评估生态系统碳循 影响 DOC 含 量 的 重 要 因 素 ( Joly et al.ꎬ 2016ꎻ
环具有重要的意义ꎮ 林地树种组成不同将会导致 Rosenfield et al.ꎬ 2020)ꎮ 针叶树中厚实的表皮和
凋落叶种类差异ꎬ进而直接影响森林土壤的物质 皮下组织对凋落叶中的组织和物质有一定的保护
组成和养分积累(Masuda et al.ꎬ 2022)ꎮ 相对于针 作用ꎬ而阔叶树硬度较低且更易破碎ꎬ使得阔叶树
叶树种ꎬ阔叶树种凋落叶的 DOC 含量较高( 林开 的可 溶 性 物 质 较 针 叶 树 种 更 容 易 淋 出 ( Don &
敏等ꎬ 2010ꎻ Joly et al.ꎬ 2016ꎻ Wu et al.ꎬ 2021)ꎮ Kalbitzꎬ 2005ꎻ 丁翊东等ꎬ2021)ꎮ 可见针叶树种
一方面ꎬ因为阔叶树凋落叶中的可溶性化合物( 如 由于本身的“ 基质质量” 影响了 DOC 的释放和产
糖类、低分子酚类化合物和次生代谢产物等) 高于 量ꎮ 因此ꎬ如何提高凋落叶分解速率和 DOC 产量