亚热带常绿阔叶林木本植物幼树阶段抽枝展叶的权衡关系  

Trade-off between shooting and leaf developing of woody species saplings in subtropical evergreen broad-leaved forests

作　　者：莫丹 王振孟 左有璐 向双[1,2] MO Dan;WANG Zhen-Meng;ZUO You-Lu;XIANG Shuang(CAS Key Laboratory of Mountain Ecological Restoration and Bioresource Utilization&Ecological Restoration and Biodiversity Conservation Key Laboratory of Sichuan Province,Chengdu Institute of Biology,Chinese Academy of Sciences,Chengdu 610041,China;University of Chinese Academy of Sciences,Beijing 100049,China)

机构地区：[1]中国科学院成都生物研究所,中国科学院山地生态恢复与生物资源利用重点实验室,生态恢复与生物多样性保育四川省重点实验室,成都610041 [2]中国科学院大学,北京100049

出　　处：《植物生态学报》2020年第10期995-1006,共12页Chinese Journal of Plant Ecology

基　　金：国家自然科学基金(31370594);国家重点研发计划(2017YFC0505000)。

摘　　要：亚热带常绿阔叶林植物幼树阶段适应林内生境并开枝散叶是其长成大树的一个重要过程,植物一年内多次抽枝的现象及其在抽枝展叶过程中小枝伸长、枝茎增粗与叶面积的增加优先顺序及其内在驱动机制还有待进一步研究。该研究对青城山常绿阔叶林木本植物多次抽枝发生比例进行了调查,并以茶(Camelliasinensis)、细枝柃(Euryaloquaiana)、短刺米槠(Castanopsis carlesii var. spinulosa)、润楠(Machilus nanmu)和大叶山矾(Symplocos grandis) 5种植物的幼树为研究对象,比较分析了植物在多次抽枝中小枝和叶片生长动态及适应策略的差异。结果显示:1)一、二次抽枝分别开始于春季(4月)和夏末(8月下旬),小枝水平上二次抽枝率乔木小于灌木,常绿植物小于落叶植物。2)一次抽枝小枝枝长、单叶面积,小枝直径和叶片数量(除大叶山矾外)均高于二次抽枝,但二次抽枝单叶面积相对生长速率均高于一次抽枝,二次抽枝叶片比叶质量(LMA)的增长速率高于一次抽枝。3)一次抽枝小枝枝长、叶片数量、小枝直径(除细枝柃和短刺米槠外)和总叶面积(除短刺米槠外)最大相对生长速率均高于二次抽枝,且大部分物种最大相对生长速率出现在抽枝开始的第一、二周。4)两次抽枝中,物种先侧重于叶片的生长,其次是小枝枝长的生长,最后是小枝直径的增粗。单叶面积和总叶面积皆随着小枝枝长和小枝直径的增加呈显著的异速生长关系,表明叶片的增长速度大于小枝。单叶面积与叶片数呈显著大于1的异速生长关系,暗示单叶面积的增长速度大于叶片数的增加速度。小枝枝长与小枝直径也呈显著大于1的异速生长关系,揭示小枝枝长的增长速度大于小枝直径。综上所述,两次抽枝过程中,植物枝叶的优先生长顺序反映了植物为获取更多的资源(尤其是光源)而形成特定的抽枝展叶策略;二次抽枝单叶面积相对生�Aims Own to their genetic characteristics and long-term adaptation to the understory environment, the saplings of subtropical evergreen broad-leaved forest woody species could shoot twigs and develop new leaves several times a year, in which how they survive in the habitats and ultimately grow to adult trees are vital. The objective of this study was to examine what specific adaptation strategies have woody plants taken in the face of environmental pressure in subtropical evergreen broad-leaved forests, especially the growth priorities of twig elongation, stem thickening and leaf area increasing during the shooting process. Methods The study site is located in Qingcheng Mountain scenic area, Sichuan Province. We chose five species with high second shooting rate in similar habits. Five plants with no disease and insect pests of each species were randomly selected for tree height measurement and long-term shooting observation. Each plant was randomly labeled with three young current-year twigs from different direction outside of tree canopy, and the twig length, twig diameter, leaf number and area were recorded when the twigs burst. The scaling relationships between traits of twig and leaf were analyzed by standardized major axis estimation(SMA). Important findings 1) The first and second shootings started from spring(April) and late summer(the late August) respectively. The proportion of the second shooting of trees was lower than that of shrubs, and the proportion of second shooting of evergreen plants was lower than that of deciduous counterparts respectively. 2) The twig length and individual leaf area, the twig diameter and leaf number(expect for the Symplocos grandis) of the first shooting were all higher than those of the second shooting, but the relative growth rate of individual area and leaf mass per area of the first shooting were lower than those of the second shooting. 3) The maximum relative growth rates of the twig length and leaf number, the twig diameter(expect for Eurya loquaiana and Castanopsis c

关 键 词：抽枝 二次抽枝 相对生长速率 异速生长 权衡 亚热带常绿阔叶林 

分 类 号：S718.5[农业科学—林学]