毛竹扩张对亚热带常绿阔叶林主要树种叶结构型性状的影响

毛竹扩张对常绿阔叶林生态系统的影响问题已成为近年国内外关注的热点问题之一。通过对常绿阔叶林和竹阔混交林内甜槠、青冈、枳椇以及青榨槭4树种主要叶结构型性状的调查与测定,分析毛竹扩张对常绿阔叶林主要树种叶结构型性状的影响。结果表明:(1)毛竹扩张不会显著改变乔木层4树种总体叶结构型性状特征。(2)不同生活型阔叶树种对毛竹扩张的响应策略不同。受毛竹扩张影响,常绿阔叶树种叶组织密度(LTD,leaf tissue density)显著减小;落叶阔叶树种叶宽(LW,leaf width)显著减小,叶形态指数(LMI,leaf morphology index)则显著增大。(3)毛竹扩张会使乔木层4树种间部分叶结构型性状差异特征发生改变,竹阔混交林中乔木层4树种间LMI、LTD、比叶面积(SLA,specific leaf area)及叶干物质含量(LDMC,leaf dry matter content)的差异特征不同于常绿阔叶林;毛竹向常绿阔叶林扩张后,甜槠叶长(LL,leaf length)、LW及叶面积(LA,leaf area)显著增大;青冈LMI显著增大,LDMC和LTD显著减小;枳椇的LMI显著增大,LW、LTD显著减小;青榨槭的LW显著减小。(4)毛竹扩张会造成乔木层树种部分叶结构型性状间关系发生改变,使林木的LL与LW、LA与LW间的截距减小,造成林木LL与LW、LA与LW之间的数量关系发生改变。

Effects of Phyllostachys Edulis expansion on leaf structural traits of main tree species in subtropical evergreen broad-leaved forests

It is increasingly recognized that effects of Phyllostachys edulis expansion on evergreen broad-leaved forest ecosystem have been become one of the concerned hot issues. To analyze effects of P. edulis expansion on leaf structural traits of main tree species in evergreen broad-leaved forest, we investigated and measured leaf structural traits of four main tree species (i.e. Castanopsis eyrei, Cyclobalanopsis glauca, Acer davidii, and Hovenia acerba) in evergreen broad-leaved forest as well as bamboo and broad-leaved mixed forest. The results showed that (1) P. edulis expansion did not significantly change character of total leaf structural traits of four arbor species. (2) Tree species of different life forms had different responses to P. edulis expansion. In response to P. edulis expansion, leaf tissue density (LTD) of evergreen broad-leaved tree species decreased significantly. Leaf width (LW) of deciduous broad-leaved tree species decreased significantly, but leaf morphology index (LMI) increased significantly. (3) The differences between partial leaf structural traits of four arbor species were altered by P. edulis expansion. The otherness of LMI, LTD, specific leaf area (SLA), and leaf dry matter content (LDMC) of four arbor species in bamboo and broad-leaved mixed forest was different from that in evergreen broad-leaved forest. Leaf length (LL), LW, and leaf area (LA) of C. eyrei increased significantly. LMI of C. glauca increased significantly, while LDMC and LTD decreased significantly. LMI of H. acerba increased significantly. LW and LTD decreased significantly. LW of A. davidii decreased significantly. (4) The differences of effects of P. edulis expansion on relationships between leaf structural traits were detected. Intercept between LL and LW, and between LA and LW of four arbor species were decreased under P. edulis expansion, so quantitative relationships between LL and LW, and between LA and LW were changed.