Modifying the floral microenvironment: elevational divergence in floral thermoregulatory mechanisms

改变花卉微环境：花卉温度调节机制的海拔差异

• 批准号: 2015459
• 负责人: Matthew Koski
• 金额: $ 45.59万
• 依托单位: Clemson University
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2020
• 资助国家: 美国
• 起止时间: 2020-09-15 至 2024-08-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=2015459&HistoricalAwards=false
• 关键词: Modifying; floral; microenvironment; elevational; divergence

Highly mobile animals can relocate to microhabitats that suit their thermal requirements when ambient temperatures are either extremely hot or cold, called thermoregulation. Plants however, are subject to ambient temperature conditions which can be detrimental to their reproductive success. This investigation will test whether high elevation populations of a wild perennial plant in the southern Colorado Rockies are locally adapted to cool temperatures, with mechanisms that increase flower temperature, whereas low elevation populations have adaptive mechanisms to lower flower temperatures under high ambient temperatures. The work will pinpoint the mechanisms by which flowers warm and cool their internal floral temperatures and test how variation in thermoregulatory ability impacts plant reproductive fitness and plant-pollinator interactions. This award will involve undergraduates at Clemson University in research in STEM fields through studies on how floral warming in local, charismatic spring ephemeral flowers impacts reproductive performance and pollination at the South Carolina Botanical Garden. As climates are changing globally and flowers continue to emerge earlier, this research will inform how plants will ameliorate thermal stress to maintain reproductive success. This work has important implications for the future of plant reproduction in both wild and economically important crop species. Angiosperms have evolved various mechanisms to achieve floral temperatures that deviate from ambient conditions, ameliorating damage to pollen and ovules and promoting pollinator visitation. Research to date is biased towards examining mechanisms of floral warming in cold environments, limiting the understanding of local adaptation in floral thermoregulation across thermal gradients and providing few examples of floral cooling. Additionally, studies linking variation in thermoregulation with variation in both gamete viability and pollinator-attraction in field conditions are scarce. This study will first test for differences in floral thermoregulation between high and low elevation populations of a widespread perennial distributed across a large altitudinal gradient in the Southern Rocky Mountains. Using growth-chamber experiments, thermal performance curves for pollen and ovule performance will be generated, and mechanisms of floral warming and cooling will be pinpointed using a combination of time-lapse photography and reflectance spectrometry. Finally, geographic variation in selection on thermoregulatory ability will be determined by linking pollen viability, seed set, and pollinator visitation with variation in floral temperature in both high and low elevation populations. This work will elucidate the complex mechanisms of floral thermoregulation and the impacts of thermoregulatory ability on plant fitness. It will shed light on how flowering plants may cope with changing temperatures and advancing phenologies in changing climates.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.

当环境温度极热或极冷时，高流动性的动物可以重新安置到适合它们温度要求的微生境，这称为体温调节。然而，植物受到环境温度条件的影响，这可能会损害它们的繁殖成功。这项调查将测试科罗拉多州南部落基山脉的一种野生多年生植物的高海拔种群是否通过提高花温的机制来适应当地的低温，而低海拔种群则具有在高环境温度下降低花温的适应机制。这项工作将查明花朵温暖和冷却其内部花朵温度的机制，并测试温度调节能力的变化如何影响植物繁殖适合性和植物与传粉者的相互作用。该奖项将让克莱姆森大学的本科生参与STEM领域的研究，通过研究当地迷人的春季短暂花朵的花朵变暖如何影响南卡罗来纳州植物园的繁殖性能和授粉。随着全球气候的变化和花朵的不断提前，这项研究将告诉我们植物将如何缓解热应激以保持繁殖成功。这项工作对未来野生和重要经济作物物种的植物繁殖具有重要意义。被子植物进化出各种机制来实现与环境条件不同的开花温度，减轻对花粉和胚珠的损害，并促进传粉者的来访。到目前为止，研究偏向于研究花在寒冷环境中变暖的机制，限制了对花跨温度梯度调节的局部适应的理解，并提供了很少的花冷却的例子。此外，将温度调节的变化与田间条件下配子活力和传粉者吸引的变化联系起来的研究很少。这项研究将首先测试分布在落基山脉南部大海拔梯度上的多年生植物高海拔和低海拔种群在花卉温度调节方面的差异。利用生长室实验，将生成花粉和胚珠表现的热性能曲线，并将结合延时摄影和反射光谱来精确定位花朵升温和冷却的机制。最后，通过将高海拔和低海拔种群的花粉生活力、结实率和授粉者访花与花温的变化联系起来，将确定温度调节能力的地理差异。这项工作将阐明花的温度调节的复杂机制以及温度调节能力对植物适合性的影响。它将阐明开花植物如何应对气候变化中的温度变化和物候变化。这一奖项反映了NSF的法定使命，并通过使用基金会的智力优势和更广泛的影响审查标准进行评估，被认为值得支持。