杉木叶片、细根功能性状对毛竹扩张及伐除的响应

Responses of leaf and fine root functional traits of Cunninghamia lanceolata to Phyllostachys edulis expansion and removal

功能性状能够反映植物对不同环境的适应策略。毛竹扩张与外来植物入侵相似,常引起原有植物生存环境的改变,而原有植物功能性状对毛竹扩张及伐除的响应机制尚不清楚。选取毛竹-杉木混交林和去竹杉木林为研究对象,以杉木纯林为对照,比较分析杉木比叶面积、叶干物质含量、叶组织密度等叶功能性状以及比根长、细根生物量、细根根长密度等细根功能性状的变化以及其间的相关关系。结果表明:(1)与杉木纯林相比,混交林中杉木的叶相对含水量以及叶干物质含量分别减少了5.07%、0.032 g/g,叶组织密度以及比叶面积分别增加了0.005 g/cm3、10.33 cm2/g;而去竹杉木林中,杉木比叶面积、叶相对含水量减少,叶干物质含量和叶组织密度则呈上升趋势。(2)与杉木纯林相比,混交林中杉木细根生物量、细根体积密度以及细根根长密度都不断下降,而杉木细根比根长在0—20 cm土深处显著增加(P<0.05);而去竹杉木林中杉木细根比根长、细根根长密度和细根生物量则显著降低(P<0.05),细根体积密度在20—30 cm土深处有所增加。(3)杉木纯林中杉木细根功能性状间相关性较为紧密,混交林及去竹杉木林中杉木叶片功能性状间相关性较高。研究表明,杉木可通过比叶面积、叶组织密度以及细根比根长等功能性状的调整及性状关联,以适应毛竹扩张或去除毛竹后引起的空间、资源竞争的变化。研究结果有利于更好地理解杉木叶片、细根对不同生境的响应特征及生态适应策略,可为毛竹林合理经营与扩张调控提供科学依据。

Functional traits can reflect the adaptation strategies of plants to different environments.The expansion of Phyllostachys edulis is similar to the invasion of alien plants,which often causes changes in the living environment of native plants.However,the response mechanism of the functional traits of native plant functional traits to the expansion and removal of Phyllostachys edulis is still unclear.The mixed forest of moso bamboo and Chinese fir and Chinese fir forest after bamboo removal were selected as the research objects,and the pure Chinese fir forest was used as the control.The changes of leaf functional traits,such as specific leaf area,dry matter content and tissue density,as well as fine root functional traits,like specific root length,fine root biomass and fine root length density,and their correlation were measured and analyzed.The results show that:(1)Compared with the pure Chinese fir forest,the leaf relative water content and leaf dry matter content of Chinese fir in mixed forest decreased by 5.07%and 0.032 g/g respectively.However,the leaf tissue density and specific leaf area in mixed forest increased by 0.005 g/cm3 and 10.33 cm2/g respectively.Compared with the pure Chinese fir forest,the specific leaf area and leaf relative water content of Chinese fir forest after bamboo removal decreased,while the leaf dry matter content and leaf tissue density increased.(2)Compared with the pure Chinese fir forest,the fine root biomass,fine root volume density and fine root length density of Cunninghamia lanceolata decreased continuously in mixed forest,but the ratio of fine root to root length increased significantly in 0-20 cm soil depth(P<0.05).Compared with the pure Chinese fir forest,fine root length,fine root length density and fine root biomass decreased significantly in Chinese fir forest after bamboo removal(P<0.05),while fine root volume density increased in soil depth of 20-30 cm.(3)The correlation between fine root functional traits of Cunninghamia lanceolata in pure forest was close,and the correlation between leaf functional traits in Chinese fir forest after bamboo removal and mixed forest was high.These results suggest that Cunninghamia lanceolata can adapt to the changes of space and resource competition caused by bamboo expansion or removal by adjusting and correlating the functional traits such as specific leaf area,leaf tissue density and fine root to root length.The results will help to better understand the response characteristics of leaves and fine roots of Cunninghamia lanceolata to different habitats and ecological adaptation strategies,and provide scientific basis for rational management and expansion regulation of bamboo forest.