Natural Selection and Evolutionary Constraints in an Elevated CO2 Environment

大气中二氧化碳(CO2)的浓度正在迅速增加，预计50年内将增加30%以上。以前的研究表明，二氧化碳浓度的增加可能会影响植物的生理、生长和生态群落。二氧化碳浓度的增加也可能影响植物产生的种子数量。这项研究将调查大气二氧化碳浓度是否会改变种子生产与植物生长、发育和抗食草动物防御的各种措施之间的关系。植物性状与种子产量之间关系的二氧化碳依赖性变化意味着，二氧化碳浓度的增加可能会影响植物性状的选择模式。换句话说，在今天的大气中产生高种子产量的植物特征可能不是在不久的将来带来高种子产量的相同特征。依赖二氧化碳的选择差异的证据将意味着，进化可能是自然群落对持续气候变化的重要反应。除了检查选择模式外，研究人员还将使用基因组技术调查种子生产、生长和反食草动物防御的遗传基础是否因植物生长的二氧化碳环境而异。所有实验工作将在明尼苏达州锡达克里克自然历史区现有的由美国国家科学基金会资助的自由空气二氧化碳浓缩实验中进行。这项研究将为几名本科生、一名研究生和一名博士后研究员提供跨学科的培训机会。本科生将在现场和实验室工作，并获得实验设计和统计分析基本原理的经验。研究生和博士后研究人员将获得植物生理学、进化和统计分析方面的专业知识。

Atmospheric concentrations of carbon dioxide (CO2) are increasing rapidly and within 50 years are expected to increase by more than 30%. Previous studies have shown that increased concentrations of CO2 may affect plant physiology, growth, and ecological communities. Increased concentrations of CO2 may also affect the number of seeds plants produce. This research will investigate whether atmospheric CO2 concentrations alter the relationship between seed production and various measures of plant growth, development, and anti-herbivore defense. CO2 dependent changes in the relationships between plant traits and seed production mean that increased CO2 concentrations may affect patterns of selection acting on plant traits. In other words, the plant traits that confer high seed production in today's atmosphere may not be the same traits that confer high seed production in the near future. Evidence for CO2-dependent differences in selection will mean that evolution may be an important response of natural communities to ongoing climate change. In addition to examining patterns of selection, the researchers will use genomic technology to investigate whether the genetic basis of seed production, growth, and anti-herbivore defense differ depending on the CO2 environment in which plants are grown. All experimental work will be conducted in an existing NSF-supported Free-Air CO2 Enrichment experiment located at Cedar Creek Natural History Area in Minnesota.This research will provide inter-disciplinary training opportunities for several undergraduate students, a graduate student, and a post-doctoral researcher. The undergraduate students will work in both the field and laboratory and gain experience with basic principles of experimental design and statistical analyses. The graduate student and post-doctoral researcher will gain expertise in plant physiology, evolution, and statistical analysis.