Collaborative Research: Alternative leaf water use strategies in hot environments

合作研究：炎热环境下的替代叶水利用策略

• 批准号: 2341692
• 负责人: Luiza Maria Teophilo Aparecido
• 金额: $ 10.72万
• 依托单位: University of Utah
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2023
• 资助国家: 美国
• 起止时间: 2023-06-15 至 2026-06-30
• 项目状态: 未结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=2341692&HistoricalAwards=false
• 关键词: Collaborative; Research; Alternative; leaf; water

Heat waves are impairing global forest productivity, ecosystem biodiversity and crop yields. In hot environments where leaf functioning is vulnerable to high temperatures, plants must cool leaves to avoid heat damage. This cooling might occur even when plants cannot photosynthesize, which is counter to the commonly understood benefit to plants of using water. However, the prevalence of these alternative water use strategies remains unknown, despite the important implications they have for understanding local, regional and global carbon and water cycles. This project will quantify alternative water use behavior across a broad range of species to determine whether this prioritization of cooling over photosynthesis is common. In turn, results will improve efforts to model vegetation responses to heat waves and identify species that are potentially best suited to cope with heat stress. The project will contribute to the training of early career scientists, graduate students, and undergraduate students in modern plant and environmental science research. Public outreach will focus on developing an outdoor exhibit for the Desert Botanical Garden, a public facility that receives approximately 500K visitors per year. The bilingual display will demonstrate to visitors the physiological and societal costs of heat waves on plants and the ways in which plants regulate their temperatures.Episodic heat waves that are increasing in duration, frequency and intensity will likely amplify plant thermal stress and mortality. Therefore, plants occurring in hot environments must cool leaves below a critical threshold that can result in permanent leaf damage. Contrary to stomatal regulation models, transpiration can achieve this cooling independent of changes in photosynthesis when conditions are thermally stressful. Recent studies have reported such alternative water use strategies in several species, which then do not maximize carbon gain for a fixed level of stomatal conductance or hydraulic risk. This project combines tightly controlled leaf gas exchange measurements with experimental manipulation of environments, and a hierarchical modeling framework in order to (1) determine the prevalence of alternative water use strategies across a diverse set of species, (2) determine the traits that best predict this behavior, (3) develop optimality theory to predict under what environmental conditions this behavior should occur, and (4) validate predictions along a broad desert – montane elevation gradient. Results will advance theory for stomatal regulation, a core topic in the fields of plant ecology and Earth system modeling. It will also provide one of the largest and most standardized datasets for plant responses to extreme environmental conditions, yielding a data resource of high value to other investigators. These findings can then be used to directly inform a revised representation of plant water use in Earth System Models. This representation will ultimately yield more useful predictions under climate change scenarios.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.

热浪正在损害全球森林生产力、生态系统生物多样性和作物产量，在叶子功能容易受到高温影响的炎热环境中，即使植物无法进行光合作用，这种冷却也可能发生，这与植物的叶子功能相反。然而，尽管这些替代用水策略对于理解当地、区域和全球碳和水循环具有重要意义，但它们的普遍性仍然未知。广泛的物种来确定这种优先顺序是否反过来，结果将改善植被对热浪反应的模拟，并确定最适合应对热应激的物种，该项目将有助于培训早期职业科学家、研究生、公共宣传活动将重点为沙漠植物园开发一个户外展览，该公共设施每年接待约 50 万名游客，双语展览将向游客展示沙漠植物园的生理和社会成本。热浪对植物的影响及其途径持续时间、频率和强度不断增加的间歇性热浪可能会加剧植物的热应激和死亡率。因此，在炎热环境中生长的植物必须将叶子冷却到临界阈值以下，这可能会导致叶子永久性损坏。与气孔调节模型相反，当条件受到热应激时，蒸腾作用可以实现光合作用变化的冷却独立性，最近的研究报告了几种物种的这种替代用水策略，但这种策略不会在气孔导度或固定水平下实现碳增益最大化。该项目将严格控制的叶片气体交换测量与环境实验操作以及分层建模框架相结合，以便（1）确定不同物种中替代用水策略的普遍性，（2）确定性状。最好地预测这种行为，（3）发展理论来预测在什么环境条件下会发生这种行为，（4）验证沿着广阔的沙漠 - 山地海拔梯度的预测结果将推进气孔调节理论，这是该领域的核心主题。植物生态学和地球系统建模领域。还将提供最大和最标准化的植物对极端环境条件反应的数据集之一，为其他研究人员提供具有高价值的数据资源，然后可以使用这些发现直接为地球系统模型中植物用水的修订表示提供信息。这种表现最终将在气候变化情景下产生更有用的预测。该奖项反映了 NSF 的法定使命，并通过使用基金会的智力价值和更广泛的影响审查标准进行评估，被认为值得支持。