Physiology, Phylogeny and Adaptation in Schiedea (Caryophyllaceae): An Endemic Hawaiian Plant Genus

9601325 Dawson本研究是对石竹科石竹科植物功能多样性模式的系统发育（进化）关系研究。一份关于雪梨属和雪梨属的系统发育（进化树）研究表明，这两个属起源于同一个祖先，并在夏威夷群岛的不同栖息地繁衍生息，包括热带雨林藤蔓、沿海和亚高山灌木以及草本植物。植物的比较生态学和生理学很少在严格的系统发育背景下进行，具有物种进化关系的知识。因此，很难知道生理、解剖和形态特征是对不同环境的适应，因为这些特征在进化过程中随着新栖息地的新选择而发生了变化，还是过去选择的历史产物。本研究将研究与繁殖系统变化相关的生理专门化模式，以及伴随栖息地偏好变化的形态。研究目标是：(1)利用固碳率和失水率、瞬时水分利用效率、碳同位素比值、水力特性及其相关形态变化等指标，描述9个代表性物种的生理多样性模式（水分利用和水分利用效率模式）；(2)分析生境特征及其与功能性状的关系；(3)从功能特征的进化关系来解释功能特征，以了解生理和形态特征的进化模式；(4)详细分析了雌雄同体物种在干旱栖息地定居和不同繁殖系统进化过程中所发生的物种内部和性别功能变化。实地研究将提供关于自然条件下功能变化的资料，而普通园林研究将提供关于在没有环境变化的受控条件下物种之间和性别之间功能变化的资料。特别是，植物的水力结构（如木结构和水运输特性）可能有助于提高木本特征的进化和干旱栖息地的殖民化，从而提高了山齿草的耐旱性。本研究是首次将植物生理生态学与系统发育系统学相结合的研究之一，有助于了解植物生理和功能性状进化的本质和模式。了解生理和其他功能特征如何随着环境的变化在进化过程中发生变化，对于理解全球气候变化如何影响原生植物和农业植物至关重要。

9601325 Dawson This research is an investigation of patterns of functional diversity with respect to their phylogenetic (evolutionary) relationships within Schiedea (Caryophyllaceae). A phylogeny (evolutionary tree) of the genera Schiedea and Alsinidendron shows that the two genera arose from the same ancestor and have radiated into diverse habitats in the Hawaiian Islands, and include rain forest vines, coastal and subalpine shrubs, and herbs. The comparative ecology and physiology of plants has rarely been conducted in a rigorous phylogenetic context, with knowledge of the evolutionary relationships of the species. As a result, it is difficult to know whether physiological, anatomical and morphological traits are adaptations to different environments because these traits have changed through evolutionary time in response to novel selection in new habitats or are historical artifacts of past selection. This research will study patterns of physiological specialization associated with shifts in breeding system and morphology that accompany shifts in habitat preference. Research objectives are: (1) to describe the patterns of physiological diversity (patterns of water use and water-use efficiency using measurements of carbon fixation and water loss rates, instantaneous water use efficiency, carbon isotope ratio, hydraulic properties, and their associated morphological changes) for 9 representative species; (2) analyze habitat characteristics and correlate them with the functional traits for these species; (3) interpret functional characteristics with respect to their evolutionary relationships to understand patterns of physiological and morphological character evolution; and (4) provide a detailed analysis of functional changes within species and by gender that have occurred as hermaphroditic species colonized drier habitats and different breeding systems evolved. Field studies will provide information about functional variation under natural conditions, and common garden studies will pr ovide information about functional variation among species and by gender under controlled conditions in the absence of environmental variation. In particular, plant hydraulic architecture (e.g., wood structure and water transport properties) is likely to have contributed to enhanced drought tolerance for Schiedea with evolution of woody features and colonization of drier habitats. This study is one of the first to merge plant physiological ecology with phylogenetic systematics, and permits an understanding of the nature and patterns of physiological and functional character evolution. Greater knowledge of how physiological and other functional characters change through evolutionary time with changes in environment is critical to understand how global climate changes will affect both native and agricultural plants.