No evidence of a generalized potential ‘cost’ of apical dominance for species that have strong apical dominance  

尚无证据表明顶端优势强的物种存在广义顶端优势潜在“成本”

作　　者：Jenna V.Finley Lonnie W.Aarssen 

机构地区：[1]Department of Biology,Queen’s University,Kingston,ON K7L 3N6,Canada

出　　处：《Journal of Plant Ecology》2022年第6期1168-1184,共17页植物生态学报（英文版）

基　　金：This work was supported by a Natural Sciences and Engineering Research Council of Canada research grant to L.W.A.

摘　　要：When the shoot apical meristem of plants is damaged or removed,fecundity and/or plant growth may suffer(under-compensation),remain unaffected(compensation)or increase(overcompensation).The latter signifies a potential‘cost’of apical dominance.Using natural populations of 19 herbaceous angiosperm species with a conspicuously vertical,apically dominant growth form,we removed(clipped)the shoot apical meristem for replicate plants early in the growing season to test for a potential cost of apical dominance.Clipped and unclipped(control)plants had their near neighbours removed,and were harvested after flowering production had finished but before seed dispersal.Dry mass was measured separately for aboveground body size(shoots),leaves,seeds and fruits;and number of leaves,fruits and seeds per plant were counted.We predicted that:(i)our study species(because of their strong apically dominant growth form)would respond to shoot apical meristem removal with greater branching intensity,and thus overcompensation in terms of fecundity and/or biomass;and(ii)overcompensation is particularly enabled for species that produce smaller but more leaves,and hence with a larger bud bank of axillary meristems available for deployment in branching and/or fruit production.Widely variable compensatory capacities were recorded,and with no significant between-species relationship with leaf size or leafing intensity—thus indicating no generalized potential cost of apical dominance.Overall,the results point to species-specific treatment effects on meristem allocation patterns,and suggest importance for effects involving local variation in resource availability,and between-species variation in phenology,life history traits and susceptibility to herbivory.破坏或去除植物顶端分生组织可能会弱化(欠补偿)、无影响(等补偿)或强化(超补偿)植物繁殖力和/或植物生长。后者为顶端优势潜在“成本”。本文选用了19种顶端生长占显著优势的垂直草本被子植物组成的自然种群为研究对象,去除(修剪)植物顶端分生组织来复制生长季节早期的植物,进而测试顶端优势潜在成本,又移除了修剪过顶端分生组织的植物与未修剪过顶端分生组织的植物(实验对照组)的邻近植物,并于开花结果后种子传播前收获所有植物,最后分别测定了地上植株(顶端)、叶片、种子及果实的干质量,并计算了每株植物的叶片、果实及种子的数量,从而得出以下预测:(i)去除顶端分生组织后,所研究物种(鉴于其生长表现为强顶端优势)的分枝强度增大,从而造成其繁殖力和/或生物量的超补偿;(ii)超补偿尤其使研究物种长出更多更小的叶片,腋生分生组织的芽库扩大,有利于分枝和/或果实生产。顶端优势的补偿能力差异很大,且其与叶片尺寸或出叶强度无显著种间关系,因此并无证据表明广义顶端优势潜在成本。总而言之,本文研究结果表明了物种特异性处理对分生组织分配模式的影响及其对局部资源可用性变化、种间物候变化、生活史特征与植食易感性的重大影响。

关 键 词：apical meristem branching intensity bud bank CLIPPING leaf size leafing intensity meristem allocation overcompensatio 

分 类 号：Q94[生物学—植物学]