DISSERTATION RESEARCH: Predicting Plant Life-Cycles in Changing Environments

生态学的一个关键目标是预测生物体将如何对气候变化做出反应。由于在大多数动植物发育的不同阶段，对温度的反应是不同的，所以必须在每个生命阶段研究这些反应。对于植物来说，每个生命阶段所处的环境由萌发、繁殖和种子传播的时间决定。植物可以利用温度、湿度和日长等环境信号来确定这些发育转变的时间，从而使生命阶段出现在一年中有利的时间段。例如，种子成熟期间的温度可以影响种子休眠的程度，种子成熟的时间和持续时间可以决定种子散布期间的季节性条件。然而，人们对种子发育过程中的环境如何影响植物的生命周期知之甚少。该项目将提供对植物拟南芥种子传播、休眠和萌发对温度的环境敏感性的经验估计，并将这些估计纳入链接的模型中，以预测植物在暴露于特定温度区域时处于每个生活期的时间。田间和生长室中的实验将表征种子成熟过程中温度变化如何改变休眠水平、关键休眠基因的基因表达水平以及种子传播的时间。这些实验将提供关于一年生植物生命周期中最鲜为人知的阶段的关键信息。将这些数据整合到生命周期模型中将改善对生物对气候变化反应的预测。这项研究对社会很重要，因为准确预测植物的生命周期时间对于预测全球变暖的生态后果以及随着植物范围在不同景观中扩大而管理杂草和其他入侵物种是必要的。该项目还将有助于对一名博士生和三名本科生进行科学培训，并通过为本科生和高中生创建一个互动教学单元，促进教育宣传。

A critical goal in ecology is to predict how organisms will respond to altered climate. Since responses to temperature differ at different stages in the development of most plants and animals, one must investigate these responses in each life stage. For plants, the environment that each life stage is exposed to is determined by the timing of germination, reproduction, and seed dispersal. Plants can use environmental cues such as temperature, moisture, and day length to time these developmental transitions so that life stages occur during favorable times of year. For example, temperature during seed maturation can influence the level of seed dormancy, and the timing and duration of seed maturation can determine the seasonal conditions during seed dispersal. However, little is known about how the environment during seed development affects plant life cycles. This project will provide empirical estimates of the environmental sensitivities to temperature of seed dispersal, dormancy, and germination in the plant Arabidopsis thaliana, and incorporate these estimates into linked models to predict when a plant will be in each of its life stages when exposed to a particular regime of temperature. Experiments in the field and in growth chambers will characterize how variable temperatures during seed maturation alter dormancy level, levels of gene expression of a key dormancy gene, and the timing of seed dispersal. The experiments will provide critical information on the least understood phase of the life cycle of annual plants. Integrating these data into the life-cycle model will improve predictions of organismal responses to changing climates.This research is important to society because accurately predictions of life-cycle timing in plants will be necessary to anticipate the ecological consequences of global warming, and to manage weeds and other invasive species as plant ranges expand across landscapes. The project will also contribute to the scientific training of a Ph.D. student and three undergraduate, and to educational outreach through the creation of an interactive teaching module for undergraduate and high school students.