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

沙漠土壤上覆盖着一层活的微生物，被称为“外壳”，其中最显眼的是苔藓。这层地壳发挥了几种有价值的生态功能，确保了植物和动物群落的持续整体健康。由于雄性罕见，莫哈韦沙漠生态系统中的主要苔藓的有性繁殖水平非常低，鉴于这种苔藓对沙漠生态系统的长期健康的重要性，本研究的目的是确定为什么有性繁殖和雄性如此罕见。指导这项研究的假设是，罕见的雄性是由于雄性在有性繁殖上花费的能量远远超过雌性，这代表了大多数植物和动物物种的角色逆转。根据这一假说的预测，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用于抗压力。将研究的压力包括高温，对干燥的耐受性，以及对接受强烈夏季降雨事件的耐受性，后者代表高温和植物组织快速干燥的组合。在对两性植物组织施加胁迫后，将采用各种措施监测其生长和恢复情况，包括死亡率、恢复生长时间、新梢产量、生长速度和光合作用效率。该方法试图将每种性别的植物暴露在实地经历的实际压力下，这些压力应该会影响这种苔藓的雄性和雌性的生长反应，从而有助于理解为什么雄性如此罕见。这项研究还应该有助于澄清存在于所有苔藓中的一种模式，雄性稀有，这似乎在沙漠中尤为明显。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.