Physiological basis of germination responses to seasonal cues in Arabidopsis thaliana

种子萌发的时间对环境条件有高度的反应。因此，如果环境发生变化，例如，由于栖息地改变、全球变暖或扩散到新的地区，发芽行为可能会作为直接和立即的反应而改变。发芽对季节线索的响应有助于基本的生活史变化，并能强烈影响种群的重要人口统计学特性，如世代时间和一代内的繁殖成功率。描述发芽对季节环境反应的遗传和生理基础，可以确定基本生活史变化的机制，并可以确定种群增长率和理想和不理想物种分布变化的原因。本研究旨在探讨拟南芥（a.thaliana）突变型和自然基因型对季节线索萌发反应的生理基础。该项目有两个组成部分。第一个成分表征了萌发对母系世代和扩散后经历的季节线索的生理基础。该成分使用一种或多种光敏色素缺陷的突变谱系，以鉴定参与发芽响应不同季节线索的光敏色素，并进一步表征光敏色素介导的调节发芽机制。突变拟南芥系将在生长室和田间的受控环境中生长。通过在受控环境和野外的研究相结合，我们将研究对影响田间发芽的真实生态线索的反应的生理基础。第二个组成部分使用可变的自然基因型来研究发芽对季节线索的自然变化的生理基础。使用自然基因型的研究将通过测试影响突变体发芽的生理机制是否也影响自然基因型的发芽来补充突变体研究。本研究将结合经典遗传学、数量遗传学和生态学操作，拓展对这种模式生物的生理学研究背景。它通过描述突变体对实际生态环境的反应，以及描述自然基因型萌发反应的生理基础来实现这一目标。因此，它将有助于我们了解生理机制中的自然变异，以及我们对自然种群中与发芽变异相关的特定基因的了解。

Timing of seed germination is highly responsive to environmental conditions. Consequently, if environments change, due to habitat alteration, global warming, or dispersal into new regions, for example, germination behavior is likely to change as a direct and immediate response. Germination responses to seasonal cues contribute to fundamental life-history variation and can strongly influence important demographic properties of populations such as generation time and reproductive success within a generation. Characterizing the genetic and physiological basis of germination responses to seasonal environments can identify mechanisms for basic life-history variation and can identify causes of variation in population growth rates and distributions in desirable and undesirable species. The proposed research is an investigation of the physiological basis of germination responses to seasonal cues in mutant and natural genotypes of A. thaliana.The project has two components. The first component characterizes the physiological basis of germination responses to seasonal cues experienced during the maternal generation and after dispersal. This component uses mutant lineages that are defective in one or more phytochromes in order to identify the phytochromes involved in germination responses to different seasonal cues, and to further characterize the phytochrome-mediated mechanisms that regulate germination. Mutant A. thaliana lines will be grown in controlled environments in growth chambers and in the field. By combining studies in controlled environments and in the field, we will investigate the physiological basis of responses to real ecological cues that influence germination in the field. The second component uses variable natural genotypes to investigate the physiological basis of natural variation in germination responses to seasonal cues. Studies using natural genotypes will complement the mutant studies by testing whether the same physiological mechanisms that influence germination in mutants also influence germination in natural genotypes.By combining classical genetics, quantitative genetics and ecological manipulations, the research will expand the context of physiological studies on this model organism. It does so by characterizing responses of mutants to actual ecological environments and by characterizing the physiological basis of germination responses of natural genotypes in addition to those of mutants. As such, it will contribute to our knowledge of natural variation in physiological mechanisms and our knowledge of specific genes associated with variation in germination in natural populations.