亚热带森林树种多样性对凋落叶分解胞外酶活性的影响  

Effects of tree diversity on enzyme activity in litter of a subtropical forest ecosystem

作　　者：潘玉梅 张乃莉 Yumei Pan;Naili Zhang(Key Laboratory for Silviculture and Conservation of Ministry of Education,College of Forestry,Beijing Forestry University,Beijing 100083)

机构地区：[1]北京林业大学林学院森林培育与保护教育部重点实验室,北京100083

出　　处：《生物多样性》2021年第11期1447-1460,共14页Biodiversity Science

基　　金：北京林业大学中央高校基本科研业务费专项资金资助(BLX202012);国家自然科学基金(32071644)。

摘　　要：森林生物多样性与生态系统功能关系是当前群落生态学的热点研究领域。然而,以往研究更多聚焦在森林植物多样性丧失对群落生产力的影响,而对森林凋落物分解的相关研究稍显不足。森林凋落叶分解的快慢直接受控于凋落物分解者分泌的胞外酶的活性,后者更是指示森林生态系统养分循环的重要指标之一。本研究依托我国江西亚热带森林生物多样性与生态系统功能控制实验,通过对不同植物多样性梯度样方内目标树种凋落叶胞外酶活性、理化性质以及腐生真菌的分析,探索树种多样性丧失对胞外酶活性的影响及其调控机制,以探讨森林树种多样性对地表、地下生态过程和功能的影响。结果表明,样方水平树种多样性丧失显著影响胞外酶的活性,除单种样方外,随着样方水平树种丰富度的增加,胞外酶活性呈现出增长趋势;与碳周转相关的α-葡萄糖苷酶(AG)、β-葡萄糖苷酶(BG)、纤维二糖水解酶(CB)在树种多样性最大时活性达到最高;而木糖苷酶(XS)以及与氮、磷和顽拗有机养分分解相关的N-乙酰-β-氨基葡萄糖苷酶(NAG)、酸性磷酸酶(AP)和多酚氧化酶(PPO)在树种多样性较低时活性较高。针对目标树种周围的邻居树种多样性进一步分析发现,各胞外酶活性随着邻居树种多样性的变化呈"单峰"响应趋势,酶活性大多在邻居树种丰富度为6时呈现峰值。研究发现真菌分解者在胞外酶活性对植物多样性的响应上可能存在重要的调控作用,可以推测树种多样性通过改变腐生真菌分解者的群落结构和多度,从而影响胞外酶活性。Aims: There is a growing concern regarding biodiversity loss and its effects on ecosystem functioning. Previous studies have primarily focused on the impact of biodiversity loss on plant productivity in forest ecosystems, but research regarding its effects on enzyme-mediated litter decomposition remains elusive. It has been well documented that the decomposers, which is an important indicator of nutrient cycling in forest ecSoscyisteemns. c Teo explore the effect of biodiversity loss on extracellular enzyme activities in litter, and the underpinning mechanism that regulates litter decomposition, a field experiment was conducted in a subtropical forest.established in Xingangshan, Jiangxi Province. In this studBy iaroea,d 3 i1 v ineternssiivtelyy studied plots which form a gradient of tree species diversity(i.e., 16 monocultures, eight 2-species mixtures, four 4-species mixtures, two 8-species mixturesand one 16-species mixture) were chosen. We collected fresh-fallen leaf litter in the plots of varying tree diversity levels and measured the extracellular enzyme activity, chemicals, and fungi in litter. We hypothesized that extracellular enzyme activities in litter, particularly those relevant to carbon(C), nitrogen(N), and phosphorus(P) cycling would significantly change with tree species diversity loss. We also expected to find that fungal decomposers could modulate the responses of enzyme activities to tree species diversity loss. Results: Our results showed that tree species diversity loss significantly affected the activities of extracellular enzymes, and extracellular enzyme activity showed a positive correlation with increasing tree species richness, except for single species. The activities of α-glucosidase(AG), β-glucosidase(BG), and cellubiosidase(CB), which are involved in C turnover, were the highest in the litter from the plot with the highest tree species diversity. Xylosidase(XS), N-acetyl-β-glucosaminidase(NAG), acid phosphatase(AP), and polyphenol oxidase(PPO), which are respectively involved in

关 键 词：酶促降解 凋落叶分解 树种多样性 邻居树种多样性 腐生真菌 亚热带森林 

分 类 号：S714[农业科学—林学]