Physiological basis of germination responses to seasonal cues in Arabidopsis thaliana

种子萌发的时间对环境条件有很高的反应。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，萌发行为可能会作为直接和立即的反应而改变。种子萌发对季节信号的反应有助于基本的生活史变化，并可强烈影响种群的重要人口统计特性，如世代时间和世代内的生殖成功。表征种子萌发对季节环境的反应的遗传和生理基础可以确定基本生活史变异的机制，并可以确定种群增长率和可取和不可取物种分布的差异原因。这项拟议的研究是对突变体和自然基因型的发芽对季节性信号的反应的生理基础的调查。该项目包括两个部分。第一组分描述了萌发对母体世代期间和散布后的季节性信号的反应的生理基础。该组件使用一个或多个光敏色素缺陷的突变谱系，以确定参与萌发对不同季节信号的反应的光敏色素，并进一步表征光敏色素介导的调节萌发的机制。突变体A.thaliana品系将在生长室内和田间受控环境中生长。通过在受控环境和田间的研究相结合，我们将调查对影响田间萌发的真实生态线索的反应的生理基础。第二部分使用不同的自然基因类型来研究种子萌发对季节信号反应的自然变异的生理基础。利用自然基因类型的研究将通过测试影响突变基因萌发的相同生理机制是否也影响自然基因类型的萌发来补充突变基因研究。通过结合经典遗传学、数量遗传学和生态调控，这项研究将扩大对这种模式生物的生理研究的背景。它通过表征突变体对实际生态环境的反应，以及除了突变体的那些之外，还表征自然基因型的萌发反应的生理基础来做到这一点。因此，它将有助于我们了解自然变异的生理机制，以及我们对与自然种群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.