Ecology and Evolution of Photosynthetic Light Responses in the Hawaiian Lobelioids

夏威夷半边莲光合光反应的生态学和进化

• 批准号: 9904366
• 负责人: Thomas Givnish
• 金额: $ 42.8万
• 依托单位: University of Wisconsin-Madison
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 1999
• 资助国家: 美国
• 起止时间: 1999-07-15 至 2003-06-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=9904366&HistoricalAwards=false
• 关键词: Ecology; Evolution; Photosynthetic; Light; Responses

The Hawaiian lobelioids are one of the most spectacular examples of ecological diversification among plants. These woody plants occur in alpine bogs, dry sea cliffs, moist scrub, and tropical rainforest interiors and edges, and display a striking variety in growth form and leaf morphology. Based on the PIs' DNA family tree for this group, these plants appear to have invaded densely shaded habitats from the open, sunny sites they occupied before and shortly after their ancestors colonized Hawaii. The central aim of this project is to understand how plants acquire photosynthetic adaptations to sunny vs. shady conditions. The PIs will attempt to reconstruct changes in photosynthetic physiology, leaf form, biochemistry, and whole-plant growth that occurred when shady habitats were invaded from open sites. Species representing groups of related Hawaiian lobelioids, including species of relatively open habitats and closely related species that have more recently invaded deeper shade, will be studied. Field studies will be conducted to characterize the natural light environments of each study species and to measure their response in leaf form and photosynthesis to light availability under natural conditions. Greenhouse studies will be conducted to determine the extent to which different lobeliads show genetic differences in photosynthetic response, leaf traits, and whole-plant growth under different light regimes. Furthermore, these studies will reveal whether species of different habitats respond to variation in light in ways thought to be advantageous (e.g., do species of sunny habitats have photosynthetic rates and leaf traits that tend to increase growth in brightly lit environments at the cost of relatively poor growth in the shade (and vice versa for species of shaded habitats), and whether understory species - which inhabit a light environment that is patchy and relatively unpredictable - show more ability to alter their photosynthetic form and physiology in response to changed light conditions than species of more open habitats. When combined with information on the evolutionary relationships among the study species, this information will tell us what changes occurred at different stages in the invasion of shaded habitats, what characteristics appear to be adaptive to shady environments, and what characteristics appear to be constrained by the evolutionary history of the different groups.This research will allow the PIs to investigate, for the first time, the rise of photosynthetic adaptations to sun vs. shade in a historical framework. The results should increase our understanding of the ecological constraints on photosynthetic performance in plants generally, and of the habitat requirements for lobelioids specifically, many species of which have become quite rare.

夏威夷叶叶菌是植物之间生态多样化的最壮观的例子之一。这些木本植物出现在高山沼泽，干海悬崖，湿擦洗和热带雨林内部和边缘，并在生长形式和叶子形态上显示出惊人的种类。这些植物基于PIS的DNA家族树，似乎从他们之前和祖先殖民夏威夷殖民后不久的开放的阳光地点侵入了密集的阴影栖息地。该项目的核心目的是了解植物如何获得对阳光与阴暗条件的光合作用。 PI将尝试重建光合生理学，叶片形式，生物化学和全植物生长的变化，这些变化是从开放地点入侵的阴暗栖息地时发生的。 将研究代表相关夏威夷叶li的种群，包括相对开放的栖息地和最近侵入更深层阴影的物种。 将进行现场研究，以表征每个研究物种的自然光环境，并以叶片形式测量其反应，并在自然条件下对光的光合作用。 将进行温室研究，以确定不同的叶出现在不同的光制状态下的光合作用反应，叶片性状和全植物生长的遗传差异的程度。 此外，这些研究将揭示不同栖息地的物种是否以被认为是有利的方式对光的变化反应（例如，阳光栖息地的物种是否具有光合作用率和叶片性状和叶片性状，这些特征和叶片性状倾向于以光明的环境增长，以相对较差的阴影增长（以及在遮阳的种类中相对较差），以及在遮阳的种类中相对较差的物种，以及是否有一个光明的物种，这是否是一个既有范围的物种，又是一种既有的又有一个，是否是一种构成的繁殖，这是一种构成的，而又有一个，并且存在着一种构成的范围。与更开放的栖息地相比，与更开放的栖息地的物种更改光合作用形式和生理学的能力。在历史框架中，光合作用适应太阳与阴影的兴起。结果应加深我们对植物光合作用的生态限制的理解，以及特别是对lobelioids的栖息地要求，其中许多物种变得非常罕见。