Genetic Adaptation to High Temperature in a Marine Alga

温度是植物分布的主要决定因素。 每个物种的耐受限度由遗传决定， 可以通过遗传适应来扩展。 高温 陆生被子植物的适应过程包括 生理和生化特性的变化，导致 光合作用和净碳的热稳定性更高， 固定 适应机制将在一个海洋 通过比较耐高温生态型 来自长岛海峡的海带， 来自缅因州的适应人群。 光合作用的适应性变化 与温度的反应，每一个生态型将检查 细节，包括热损伤的时间依赖性和可逆性， 和高温诱导的光抑制。 热响应 暗呼吸和光呼吸也将进行比较， 每株植物 光系统II的热稳定性，最热- 光合作用的敏感成分，将使用 叶绿素荧光技术。 调的自适应变化 光合和呼吸酶将由 通过比较体外的热性能和比较 植物暴露在超适宜温度下。 结果将 提供迄今为止有关机制的最全面信息 通过该方法船用发动机可以扩展其温度耐受性， 因此，它的地理和环境范围。

Temperature is a primary determinant of the distribution of plants. Tolerance limits of each species are genetically determined, and can be extended through genetic adaptation. High-temperature adaptation in terrestrial angiosperms has been shown to involve changes in physiological and biochemical traits, resulting in greater thermal stability of photosynthesis and net carbon- fixation. Mechanisms of adaptation will be examined in a marine alga by comparing traits of a high-temperature tolerant ecotype of the kelp, Laminaria saccharina, from Long Island Sound and a non adapted population from Maine. Adaptive changes in photosynthesis vs. temperature responses of each ecotype will be examined in detail, including time-dependence and reversibility of heat damage, and high-temperature induced photo inhibition. Thermal responses of dark respiration and photo respiration will also be compared for each plant. Thermal stability of photosystem II, the most heat- sensitive component of photosynthesis, will be examined using chlorophyll fluorescence techniques. Adaptive changes in key photosynthetic and respiratory enzymes will be determined by comparing thermal properties in vitro and by comparing activity in plants exposed to superoptimal temperatures. The results will provide the most comprehensive information to date about mechanisms by which a marine alga can extend its temperature tolerance and, thereby, its geographic and environmental ranges.