Delineating the Roles of Rising CO2 and Temperature on Flowering Time across Pre-industrial through Future Conditions

描述从工业化前到未来条件下二氧化碳和温度上升对开花时间的作用

• 批准号: 1457236
• 负责人: Lena Hileman
• 金额: $ 68.12万
• 依托单位: University of Kansas Center for Research Inc
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2015
• 资助国家: 美国
• 起止时间: 2015-05-01 至 2022-04-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1457236&HistoricalAwards=false
• 关键词: Delineating; Roles; Rising; CO2; Temperature

Flowering time has a large influence on ecological and evolutionary processes of plants. If flowering time is delayed, reproduction may be insufficient or may fail if seed set is not achieved by the end of the growing season. In contrast, if the transition to flowering is too rapid, the full length of the growing season may not be utilized for optimizing reproduction. As a result, shifts in flowering time can alter plant productivity, disrupt plant-pollinator interactions, and affect food production in crops. Climate change is expected to have major impacts on the flowering times of plants. While some species are known to have flowered earlier over the last century in response to warming, others may be more influenced by rising atmospheric carbon dioxide, or both factors combined. Little is known about the mechanisms that drive elevated carbon dioxide effects on flowering time. This may prove problematic, since over half of plant species are known to exhibit major alterations in flowering time when grown at elevated carbon dioxide levels predicted for 50 years into the future. Such responses will have global implications since carbon dioxide is rising across the planet. The overall goal of this research is to better understand the linkages between growth, physiological, and molecular mechanisms that control flowering time in response to both rising carbon dioxide and temperature across contemporary through future time scales. The Principal Investigator will help develop the new "Flower and Food Garden of Southwest Middle School" in Lawrence, KS, which will be an educational garden where students will apply current adaptation strategies in planting times under climate change scenarios and will measure food production. This will enable students to conduct hands-on research, analyze their own data, and report their findings to the community. Moreover, these outreach efforts will help to develop a more informed society on the effects of climate change on plants. These efforts will also promote a stronger workforce that will enable strategies to overcome the negative effects of climate change on food production through increased understanding of plant mechanistic responses to the environment.The goal of this research is to better understand the linkages between growth, physiological, and molecular mechanisms that control flowering time (FLT) in response to both rising [CO2] and temperature across pre-industrial through future conditions. In preliminary studies with field-collected genotypes of Arabidopsis thaliana, it was determined that rising [CO2] was the main driver of accelerated FLTs between preindustrial and modern conditions, while surprisingly, the addition of higher temperature reduced or eliminated this response. These are among the first results to delineate the effects of rising [CO2] and temperature that occurred over the last century on FLT. Furthermore, between modern and future conditions, high levels of variation were observed among genotypes for FLT responses, which would have major ecological and evolutionary implications if represented in other species. It is becoming increasingly clear that the influence of increasing [CO2] and temperature on FLT is not simply due to effects on growth rate. Rather, physiological responses and metabolite production can affect signaling mechanisms that influence flowering gene expression and alter the timing and size at which plants flower in response to climate change factors. Therefore, the proposed research takes an integrative approach to determine how the upstream effects of whole-plant growth, leaf-level physiology, and metabolite production interact to influence downstream effects on flowering gene expression and ultimately FLT in model plants and crops. Path analysis is used to determine the causal pathways that are most likely influencing FLT in response to [CO2] and temperature. Ultimately, the physiological, developmental, and molecular understanding developed in this research will increase the ability to predict FLT responses to contemporary and future changes in climate. The PI has a strong track-record of mentoring undergraduate students, including those from underrepresented populations, and this will continue throughout this research.

开花时间对植物的生态和进化过程有很大影响。如果开花时间延迟，繁殖可能会不足，或者如果在生长季节结束时未结籽，繁殖可能会失败。相反，如果向开花的过渡太快，则可能无法利用整个生长季节来优化繁殖。因此，开花时间的变化会改变植物生产力，破坏植物与传粉媒介的相互作用，并影响农作物的粮食生产。气候变化预计将对植物的开花时间产生重大影响。虽然已知某些物种在上世纪早些时候因气候变暖而开花，但其他物种可能更多地受到大气二氧化碳上升或这两种因素综合的影响。关于二氧化碳对开花时间影响增加的机制知之甚少。这可能被证明是有问题的，因为已知超过一半的植物物种在预计未来 50 年内在较高的二氧化碳水平下生长时，会表现出开花时间的重大变化。由于全球二氧化碳排放量正在上升，此类应对措施将产生全球影响。这项研究的总体目标是更好地了解生长、生理和分子机制之间的联系，这些机制控制开花时间，以响应当代到未来时间尺度的二氧化碳和温度上升。首席研究员将帮助在堪萨斯州劳伦斯开发新的“西南中学花卉和食品花园”，这将是一个教育花园，学生将在气候变化情景下的种植时间中应用当前的适应策略，并测量粮食产量。这将使学生能够进行实践研究、分析自己的数据并向社区报告他们的发现。此外，这些外展工作将有助于建立一个更加了解气候变化对植物影响的社会。这些努力还将促进一支更强大的劳动力队伍，通过加深对植物对环境的机械反应的了解，制定克服气候变化对粮食生产负面影响的战略。这项研究的目标是更好地了解生长、生理、以及控制开花时间（FLT）的分子机制，以响应工业化前到未来条件下的[CO2]和温度上升。在对现场收集的拟南芥基因型进行的初步研究中，确定[CO2]上升是工业化前和现代条件之间FLT加速的主要驱动因素，而令人惊讶的是，更高温度的增加减少或消除了这种反应。这些是描绘上个世纪发生的 [CO2] 上升和气温上升对 FLT 影响的首批结果之一。此外，在现代和未来的条件下，FLT 反应的基因型之间观察到了高水平的变异，如果在其他物种中出现，这将产生重大的生态和进化影响。越来越明显的是，增加 [CO2] 和温度对 FLT 的影响不仅仅是对生长速率的影响。相反，生理反应和代谢产物的产生可以影响信号机制，从而影响开花基因表达并改变植物响应气候变化因素开花的时间和大小。因此，本研究采用综合方法来确定全植物生长、叶级生理和代谢物产生的上游效应如何相互作用，从而影响模型植物和作物中开花基因表达以及最终 FLT 的下游效应。路径分析用于确定最有可能影响 FLT 对 [CO2] 和温度的响应的因果路径。最终，本研究中开发的生理、发育和分子理解将提高预测 FLT 对当前和未来气候变化的反应的能力。 PI 在指导本科生（包括来自代表性不足群体的学生）方面拥有良好的记录，并且这将在整个研究中继续下去。