Exploring the `Harperian' paradox: Leaving descendants in a crowded plant world

近邻之间的竞争是常规的 被认为是自然选择形成的最强烈的力量之一 植物功能性状的进化和多样性。大多数 资源条件下植物成功进化策略的传统理论 限制(竞争力)是基于规模优势的假设， 优势通常包括在吸收/耗尽 有争议的资源，因此通常与更大的增长相关 积累量和更大的最大潜在身体尺寸(Max)。我最近的研究 然而，指出了另一种解释，涉及生殖 经济优势假说，生殖成功在严重范围内 拥挤的社区通常更大，而不是拥有更大MAX的物种， 但对于繁殖力分配较高的物种，即生产更大的 每只后代(有性或无性系)数量 单位时间内的单亲工厂大小。这里提出的研究将使用温室 自然植被研究、野外实验和大规模人口普查 对加拿大安大略省东部的区域植物区系进行调查，以确定主要的 生育力分配的组成部分，因此也就是生殖经济能力 在开花植物中。重点将放在濒危物种和植被上。 与用于农业的边际土地的生态系统服务有关(例如，老土地 字段)。主要的预测是，高生育力的分配是由 四个可能的大小度量：(I)相对较小的最小(最小阈值 产生种子或克隆后代的亲本体型)；(Ii)相对 高地上体质量密度(单位物理质量的干质量 占用空间)；(3)相对较小的种子大小，即所有 在其他条件相同的情况下，结出较小种子的植物可以产生更多的种子。 单位植物体大小；及(Iv)相对较小的叶大小，即 长出较小叶子的植物可以为给定的身体大小长出更多的叶子 支持营养组织(更高的叶片强度)，这使得 更大的腋芽库‘(每单位身体大小)可用于部署 克隆和/或有性生殖分生组织。我们可以预测，拥有更大的芽库也意味着更多的分生组织 可用于在以下方面进行战略部署 建筑/生长形态可塑性(例如，在不同光照条件下的分枝强度)，或AS 在食草动物失去组织后的生存和补偿储备 或者是骚乱。这些项目将在五年内培训2名博士生，4-5名硕士学生和10名本科生论文学生，平均每年有3-4名研究生和2名理科(荣誉)论文学生/暑期学生技术员在我的实验室工作。

Competition between near neighbours is conventionally regarded as one of the most intense forces of natural selection that has shaped the evolution and diversity of functional traits in plants. Most of the traditional theory for evolved strategies of success in plants under resource limitation (competitive ability) is based on a Size Advantage' hypothesis, where superiority involves generally greater success in uptake/depletion of contested resources, typically associated therefore with greater growth accumulation and larger maximum potential body size (MAX). My recent research however points to an alternative interpretation involving a Reproductive Economy Advantage' hypothesis, where reproductive success within severely crowded neighbourhoods is generally greater, not for species with larger MAX, but for species with higher fecundity allocation', i.e. production of a larger number of offspring (sexual or clonal) per unit parent plant size per unit time. The research proposed here will use greenhouse studies, field experiments in natural vegetation, and large scale census surveys of the regional flora in eastern Ontario, Canada to identify the major components of fecundity allocation and hence capacity for reproductive economy in flowering plants. Emphasis will be placed on species at risk and vegetation associated with ecosystem services of marginal lands for agriculture (e.g. old fields). The main predictions are that high fecundity allocation is promoted by four potential size metrics: (i) relatively small MIN (minimum threshold parental body size for producing seed or clonal offspring); (ii) relatively high above-ground body mass density (dry mass per unit of physical space occupancy); (iii) relatively small seed size i.e. all else being equal, a plant that makes smaller seeds, can make more of them per unit plant body size; and (iv) relatively small leaf size i.e. a plant that makes smaller leaves can make more leaves for a given body size of supporting vegetative tissue (a higher leafing intensity'), which enables a larger axillary bud bank' (per unit body size) available for deployment as clonal and/or sexual reproductive meristems. Having a larger bud bank, we can predict, also means that more meristems are available for strategic deployment in the expression of architectural/growth-form plasticity (e.g. for branching intensity under variable light regimes), or as a reserve' for survival and compensation following tissue loss to herbivores or disturbance. These projects, over five years, will involve training for 2 PhD students, 4-5 MSc students, and 10 undergraduate thesis students with an average of 3-4 graduate students and 2 BSc (Hons) thesis students / summer student technicians working in my lab each year.