王芳 林敦梅

摘要：文章以重庆市主城区22个常见绿化树种为研究对象，通过蒸馏水浸泡法测定凋落叶的持水特性;再通过测定不同树种凋落叶的性状，分析其与凋落叶持水特性之间的关系。结果表明：随着浸泡时间的增加，所有树种凋落叶的吸水量呈对数增加;不同树种凋落叶的标准持水力（浸泡1 h）和最大持水力（浸泡24 h）均存在显著差异（P<0.001），其中黄葛树的标准持水力最大（90.5±2.1）%，鸳鸯茉莉的最大持水力最大（268.0±22.5）%，而蚊母树的标准持水力（5.8±0.4）%和最大持水力（21.3±2.3）%均最小;标准持水力和最大持水力均与叶干物质含量呈显著负相关关系，最大持水力还与比叶面积呈显著正相关关系，说明叶的性状可以预测其凋落叶的持水力特性。基于研究结果，在城市绿地中选择种植鸳鸯茉莉、红背桂、金丝桃、栀子花等灌木，以及黄葛树、广玉兰等乔木将更有利于提高城市森林凋落物层的水源涵养能力。研究结果可为提升城市绿地水源涵养功能的树种选择提供参考。

关键词：绿化树种，凋落叶，叶片性状，持水特性，水源涵养

DOI： 10.12169/zgcsly.2021.03.28.0003

Abstract： In this study， we measure leaf litter water holding capacity of 22 greening tree species which are widely planted in the core area of Chongqing by using steam distillation method， and also test their leaf traits， in order to analyze the relationships between leaf traits and water holding capacity of leaf litters. The results show that leaf litters water absorption increases logarithmically with soaking time， and the standard water holding capacity （soaking 1 hour） and maximum water holding capacity （soaking 24 hour） of leaf litters of different tree species differ significantly （P<0.001）. Among the 22 species tested， Ficus virens has the highest standard water holding capacity （90.5±2.1）% and Brunfelsia acuminata has the highest maximum water holding capacity （268.0±22.5）%， while Distylium racemosum is the tree species which is lowest in both standard water holding capacity （5.8±0.4）% and maximum water holding capacity （21.3±2.3）%. Standard water holding capacity and maximum water holding capacity are both significantly negatively correlated to leaf dry matter content， and maximum water holding capacity is also significantly positively correlated to specific leaf area. This result suggests that leaf traits can be used to predict the water holding capacity of leaf litters. Based on the results， we recommend B. acuminata， Excoecaria cochinchinensis， Hypericum monogynum， Gardenia jasminoides， F. virens and Magnolia grandiflora as the priority greening tree species in order to increase the litter layer capacity of water conservation in urban forest. This study provides some suggestion for the selection of greening tree species to improve the water conservation function of urban green space.

Keywords： greening tree species， leaf litter， leaf trait， water holding characteristics， water conservation

森林通過林冠层、凋落物层和土壤层拦蓄降水、调节地表径流和净化水质，从而在水土保持和水源涵养方面为人类提供重要的生态系统服务[1-4]。凋落物层不仅通过分解为植物生长提供养分，还具有重要的水文调节功能[3，5]。凋落物层通过截留和吸收降水，抑制土壤水分蒸发，增强地表和土壤的持水能力，在森林水源涵养和水土保持方面发挥着重要作用[6]。……