Collaborative Research: Linking Abiotic Stress to Gender Specific Fitness in a Desert Bryophyte

沙漠土壤被称为“地壳”的活的微生物覆盖，其中最引人注目的是苔藓。 这种外壳执行几个有价值的生态功能，确保植物和动物群落的持续整体健康。 在莫哈韦沙漠生态系统的主要苔藓的特点是非常低的水平，由于男性罕见的有性生殖，并考虑到这种苔藓的重要性，长期健康的沙漠生态系统，本研究的目的是确定为什么有性生殖和男性是如此罕见。 指导这项研究的假设是，罕见的雄性是由于雄性在有性生殖方面比雌性花费更多的能量，这代表了大多数植物和动物物种中的角色颠倒。 根据这一假设的预测，男性应该比女性更容易受到压力的影响，因为女性有更多的可用资源来承受压力。 将研究的胁迫包括高温、对干燥的耐受性以及对夏季强降雨事件的耐受性，后者代表高温和植物组织快速干燥的组合。 在对每种性别的植物组织施加胁迫后，将使用多种测量来监测生长和恢复，包括死亡率、恢复生长的时间、产生的芽、生长速率和光合作用的效率。 这种方法旨在将每种性别的植物暴露在实地经历的现实压力下，这些压力应该会影响这种苔藓的雄性和雌性的生长反应，从而有助于了解为什么雄性如此罕见。 这项研究还应该有助于澄清所有苔藓中存在的一种模式，即雄性稀有，这似乎在沙漠中特别明显。 该项目的影响包括与气候变化影响的直接联系，以及增加少数民族学生参与研究的机会。

Desert soils are coated with living microscopic organisms, known as the "crust", with mosses among the most conspicuous of these organisms. This crust performs several valuable ecological functions that ensure thecontinued overall health of the plant and animal community. The principal moss in the Mojave Desert ecosystem is characterized by very low levels of sexual reproduction due to male rarity, and given the importance of this moss to the long term health of the desert ecosystem, the aim of this study is to determine why sexual reproduction and males are so rare. The hypothesis guiding the research is that rare males result from males expending far more energy toward sexual reproduction than females, representing a reversal of roles found in most species of plants and animals. Predictions from this hypothesis include that males should be more vulnerable to stress than females, because females have more available resources to expend on stress tolerance. Stresses that will be studied include high temperatures, tolerance to drying out, and tolerance to receiving intense summer rainfall events, with the latter events representing a combination of high temperatures followed by quick drying of plant tissues. Following application of stress to plant tissues of each sex, growth and recovery will be monitored using a variety of measures, including mortality, time to resumption of growth, shoots produced, growth rate, and the efficiency of photosynthesis. The approach seeks to expose plants of each sex to realistic stresses experienced in the field that should influence the growth responses of males and females of this moss, thereby helping gain an understanding of why males are so rare. The research should also help to clarify one of the patterns that exist across all of the mosses, male rarity, which appears to be especially manifested in deserts. The project impacts include direct connections to impacts of climate change and increasing opportunities to involve minority students in research.