凋落物分解与细根生长的相互作用  

Interaction of Litter Decomposition and Fine-Root Growth

作　　者：王微[1,2] 胡凯[2] 党成强[1] 陶建平[1] 

机构地区：[1]三峡库区生态环境教育部重点实验室重庆市三峡库区植物生态与资源重点实验室西南大学生命科学学院,重庆400715 [2]重庆文理学院林学与生命科学学院,重庆402168

出　　处：《林业科学》2016年第4期100-109,共10页Scientia Silvae Sinicae

基　　金：重庆市自然科学基金项目(cstc2013jcyj A20019);重庆市教委科学技术研究项目(KJ131201)

摘　　要：本文综述了细根在凋落物层的觅食行为与策略,细根生长与凋落物数量、质量及分解过程的关系,细根生长与凋落物分解的相互作用机制及影响因素等以期为理解森林生态系统中细根对凋落物分解的作用机制以及凋落物分解对细根生长的影响提供依据。一方面,凋落物的数量和质量影响细根生长,地上凋落物的数量影响细根的觅食行为,并驱动细根在凋落物层的生长动态,凋落物质量的差异也对细根的生长产生影响,不同性质的地上凋落物对细根的生长是促进还是阻碍主要取决于分解过程中所产生的养分以及多酚含量的正平衡或负平衡;另一方面,生长进入凋落物层的细根通过根际激发效应、养分吸收以及共生真菌等作用综合影响凋落物的分解过程,生活的细根对凋落物分解的激发效应主要表现在根系分泌物控制微生物群落的活力及组成,进而加速或抑制凋落物分解;N的有效性是影响凋落物分解的重要因素,处于分解后期的凋落物层中生长的细根,通过吸收凋落物表面矿化形成的大量无机N,避免过量的N对微生物群落及其生境的不利影响;根系的共生伙伴——菌根真菌也对凋落物的分解产生重要影响,这与真菌类型及其分泌的酶和有机酸有关。未来该领域应注重全球变化背景下细根生长对凋落物分解作用机制以及细根的分支结构与其获取凋落物层养分功能的联系等方面的研究。In different forest ecosystems,fine roots commonly proliferate into litter layers,especially into those with favorable conditions for root growth. Our aim is to provide a basis for better understanding the role and mechanism of action in litter decomposition by fine roots and the influence of litter decomposition on fine root growth. We reviewed the advances of recent studies,including how roots forage into litter,the factors influencing this foraging,and the influence and possible mechanisms of fine root growth on litter decomposition. We put forward a conceptual module that enhances understanding of the interaction between fine-root growth and litter decomposition. Litter quantity on the soil surface affects the foraging behavior of fine-roots and drives their growth dynamics. Litter quality can also affect fine-root growth.Fine-root growth enhancement or inhibition could be the result of a positive or negative balance between nutrient and polyphenols concentrations generated during the decomposition of litter with different properties. By proliferating in litter,fine roots potentially influence litter decomposition through priming effects,N uptake,and symbiotic mycorrhizal fungi.The priming effects of live fine-roots on litter decomposition are mainly manifested by root exudate C inputs,which can regulate decomposition of litter by controlling the activity and composition of the microbial community. Nitrogen availability is critically important to litter decomposition,and low N availability can increase decomposition as microbes use labile substrates to acquire N from recalcitrant organic matter. Fine-roots grow into a decomposed litter layer,which avoid the adverse effects of excess N on microorganisms by absorbing a large amount of inorganic N during litter mineralization. Inaddition,root symbiotic partners,i. e.,mycorrhizal fungi,have an important impact on litter decomposition through the types of fungi and enzymes and organic acids secretion. Key scientific issues for future research include the mechanism

关 键 词：凋落物 分解 细根生长 根系觅食 菌根真菌 地下生态过程 

分 类 号：S718.52[农业科学—林学] Q948.12[生物学—植物学]