Effect of a Seed Bank on the Evolution of Post-Germination Traits: An Empircal Study of the Desert Mustard Lesquerella fendleri

当面临不利的环境条件时，许多生物的反应是减缓或停止生长和发育。在天平的一端，像熊这样的动物有能力通过冬眠来减缓新陈代谢。在光谱的另一端，许多高等植物有能力或多或少地阻止种子的生长和发育，直到经历了有利的条件。种子的休眠导致了种子库的存在——土壤中休眠的、可存活的种子种群。尽管休眠对植物的生态学和进化有着深远的影响，但实际上没有关于休眠如何影响其他性状的信息。两个实验将在短命的多年生沙漠芥菜Lesquerella fendleri中解决这个问题。第一篇探讨了过去的进化是否导致了萌发要求和萌发后性状的适应性综合征。第二个问题是，进化如何通过进行人工选择实验来发挥作用。这项工作有几个方面的应用价值。了解植物对环境变化的反应的努力将仍然是不完整的（也许是错误的），直到我们了解生命周期中重要但被忽视的种子阶段。对种子阶段的了解对于人类影响的土地的恢复计划也是至关重要的。

Evans 9318433 Many organisms, when faced with unfavorable environmental conditions, respond by slowing or arresting growth and development. At one end of the scale, animals such as bears have the ability to slow metabolism by hibernating. At the other end of the spectrum, many higher plants have the ability to more or less arrest growth and development of seeds until favorable conditions are experienced. This dormancy of seeds has led to the existence of seed banks--populations of dormant, viable seeds in the soil. Despite the profound implications for the ecology and evolution of plants, virtually no information is available on how dormancy affects other traits. Two experiments will address this question in the short-lived perennial desert mustard Lesquerella fendleri. The first explores whether past evolution has led to adaptive syndromes of germination requirements and post- germination traits. The second asks how evolution could act by performing an artificial selection experiment. This work has applied value in several regards. Efforts to understand plant responses to environmental change will remain incomplete (and perhaps erroneous) until we understand the important, but neglected, seed stage of the life cycle. Knowledge of the seed stage is also critical for plans to revegetate human- impacted lands.