DISSERTATION RESEARCH: Adaptation and historical ecology in vernal pool Eryngium (Apiaceae)

论文研究：春池刺蓟属（伞形科）的适应和历史生态学

• 批准号: 0909804
• 负责人: Bruce Baldwin
• 金额: $ 1.2万
• 依托单位: University of California-Berkeley
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2009
• 资助国家: 美国
• 起止时间: 2009-07-01 至 2012-12-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0909804&HistoricalAwards=false
• 关键词: DISSERTATION; RESEARCH; Adaptation; historical; ecology

Vernal pools are island-like depressions characterized by seasonal extremes: flooding during winter and desiccation during summer; they are home to many endangered plants and animals. In such habitats, plants and animals must possess extreme adaptations. Many species of Eryngium occupy Californian vernal pools; these plants are closely related to carrots and parsnips. In this study, adaptations in Eryngium will be viewed from a historical perspective. DNA sequences will be collected from related species of Eryngium from California, Oregon, and Chile -- some restricted to vernal pools and some from normal terrestrial habitats. Relationships between these plants will be reconstructed from their DNA sequences. This history will give insights into how a specific adaptation, seasonal changes in leaf form, may have arisen. In Eryngium, as well as other vernal-pool plants, two types of leaves are produced: (1) winter leaves, which are well suited to flooded environments but as a trade-off produce less energy than (2) summer leaves, which are poorly suited to winter flooding. An experiment will be conducted to determine if the shift from winter leaves to summer leaves is triggered by increases in the amount of daylight per day during spring, and to determine whether leaf development is tightly constrained by genetics or if it can respond adaptively to changing environmental conditions. An important question to biologists to be addressed is whether specialization of habitat is irreversible: If plants adapt to vernal pools, are they trapped by their success? Many species of Eryngium in the vernal pools of California are in peril, and an answer to this question along with improvements in the understanding of the life history of Eryngium will aid conservation efforts. The experiment in this study gives opportunity for underrepresented minorities to learn scientific research techniques otherwise not available to undergraduates.

春池是岛屿状的洼地，具有极端的季节性特征：冬季洪水，夏季干旱；它们是许多濒危植物和动物的家园。在这样的栖息地中，植物和动物必须具有极端的适应能力。许多刺梨属植物占据了加州的春季水池。这些植物与胡萝卜和防风草密切相关。在这项研究中，将从历史的角度来看待刺蓟属的适应。 DNA 序列将从加利福尼亚州、俄勒冈州和智利的相关刺蓟属物种中收集，其中一些仅限于春季水池，一些来自正常的陆地栖息地。这些植物之间的关系将根据它们的 DNA 序列进行重建。这段历史将让我们深入了解一种特定的适应，即叶子形状的季节性变化，是如何发生的。刺蓟以及其他春池植物会产生两种类型的叶子：（1）冬季叶子，非常适合洪水环境，但作为权衡，产生的能量比（2）夏季叶子少，夏季叶子是不适合冬季洪水。将进行一项实验，以确定从冬季叶子到夏季叶子的转变是否是由春季每天日照量的增加引发的，并确定叶子的发育是否受到遗传的严格限制，或者是否能够对不断变化的环境做出适应性反应状况。 生物学家需要解决的一个重要问题是，栖息地的专门化是否是不可逆转的：如果植物适应了春季池，它们是否会被成功所困？加利福尼亚州春天池中的许多刺梨属植物正面临危险，这个问题的答案以及对刺梨属生命史的了解的加深将有助于保护工作。这项研究中的实验为代表性不足的少数群体提供了学习本科生无法获得的科学研究技术的机会。