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

开花时间对植物的生态和进化过程有很大影响。如果开花时间推迟，繁殖可能不充分，或者在生长季结束前没有结实的情况下可能失败。相反，如果过渡到开花太快，整个生长季可能不会被用于优化繁殖。因此，开花时间的改变可能会改变植物的生产力，扰乱植物与传粉者的相互作用，并影响作物的粮食产量。气候变化预计将对植物的开花时间产生重大影响。虽然众所周知，一些物种在上个世纪开花更早是为了应对气候变暖，但其他物种可能更多地受到大气二氧化碳上升的影响，或者两者兼而有之。关于二氧化碳升高对开花时间的影响的机制，人们知之甚少。这可能会被证明是有问题的，因为已知有超过一半的植物物种在未来50年内预测的较高二氧化碳水平下生长时，开花时间会发生重大变化。这样的反应将产生全球影响，因为二氧化碳正在全球范围内上升。这项研究的总体目标是通过未来的时间尺度，更好地了解控制开花时间的生长、生理和分子机制之间的联系，以响应当代二氧化碳和温度的上升。首席调查员将帮助开发位于肯塔基州劳伦斯的新的“西南中学花卉食品园”，这将是一个教育花园，学生将在气候变化情景下的种植期应用当前的适应策略，并将衡量粮食产量。这将使学生能够进行实践研究，分析自己的数据，并向社会报告他们的发现。此外，这些外展工作将有助于发展一个更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，这将使通过增加对植物对环境的机械反应的了解来克服气候变化对粮食生产的负面影响的战略成为可能。本研究的目标是通过未来条件更好地了解控制开花时间(Flt)的生长、生理和分子机制之间的联系，以响应工业化前的[CO2]和温度上升。在对田间采集的拟南芥基因型的初步研究中，确定了在工业化前和现代条件下，[CO2]升高是加速FLTS的主要驱动因素，而令人惊讶的是，更高的温度降低或消除了这种反应。这些都是描述上个世纪发生的二氧化碳浓度上升和气温升高对外语教学影响的首批结果之一。此外，在现代和未来的条件下，观察到了Flt反应的不同基因型之间的高度变异，如果这种变异出现在其他物种中，将具有重大的生态和进化意义。越来越清楚的是，[CO2]和温度升高对FLT的影响不仅仅是由于对生长速度的影响。相反，生理反应和代谢产物的产生可以影响信号机制，从而影响开花基因的表达，并改变植物开花的时间和大小，以响应气候变化因素。因此，这项研究采用综合的方法来确定整个植物生长、叶片水平的生理和代谢物产生的上游效应如何相互作用，从而影响模式植物和作物的开花基因表达并最终影响Flt。通径分析被用来确定最有可能影响外语教学对[CO2]和温度的反应的因果路径。最终，这项研究中发展起来的生理、发育和分子方面的理解将提高预测外语教学对当代和未来气候变化的反应的能力。PI在指导本科生方面有着很好的记录，包括那些来自代表人数不足的人群的学生，这将在整个研究过程中继续下去。

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.