Thermal Adaptation in Polar Macroalgae

Gerard 9521496使某些植物物种能够在全年温度接近或低于0 ℃的极地环境中生存和生长的遗传适应性知之甚少。 低温适应在陆生植物中由于冻结、干燥和气孔导度而变得复杂，在海洋浮游植物中由于多变和不可预测的物理环境而变得复杂。 极地大型藻类提供了一种实验系统，该系统不受这些并发症的影响，并且非常适合于研究植物的冷适应。 南极大型藻类的冷适应能力特别发达，它们在0 ℃时的光合作用和生长速度与温带物种在10- 15 ℃时的速度相当。 这项拟议中的研究使用了北极和南极特有的海藻来回答这个问题：“极地海藻拥有什么样的适应能力，使它们能够吸收碳并在非常低的温度下快速生长？" 研究了3对极温性褐藻的碳代谢特征：北极海带（Laminaria solidungula）和温带海带（Laminaria saccharina）;南极海带（Desmarestia anceps）和温带海带（Desmarestia aculeata）; anceps，但形态上类似于海带saccharina。 碳代谢过程（光合作用，呼吸作用和光独立的碳固定）是重要的冷适应将被确定在适应相同温度的每个物种对孢子体。 具体的适应机制将通过比较光合机构的组成以及参与光合作用、呼吸作用和非光依赖性碳固定的关键酶的含量、活性和热特性来确定。 多个物种对和一套广泛的碳同化参数的比较，将提供一个全面的分析，在北极和南极海洋特有的藻类物种的低温适应机制，并增加在所有植物的低温适应的整体理解。

Gerard 9521496 The genetic adaptations that enable certain plant species to survive and grow in polar environments where temperatures are near or below 0oC year-round are poorly understood. Low- temperature adaptation is complicated in terrestrial plants by freezing, desiccation and stomatal conductance, and in marine phytoplankton by a variable and unpredictable physical environment. Polar macroalgae provide an experimental system that is not subject to these complications and that is well- suited to the study of cold-adaptation in plants. Cold- adaptation is particularly well developed in Antarctic macroalgae, in which rates of photosynthesis and growth at OoC are comparable to rates achieved at 10-15oC by temperate species. The proposed research uses endemic Arctic and Antarctic seaweeds to answer the question, "What adaptations do polar algae possess that enable them to assimilate carbon and grow rapidly at very low temperatures?" The research focusses on carbon-metabolism characteristics of three closely related polar-temperate pairs of brown algae: Arctic Laminaria solidungula and temperate Laminaria saccharina; Antarctic Desmarestia anceps and temperate Desmarestia aculeata, and Antarctic Himantothallus grandifolius that is related to Desmarestia aculeata and D. anceps, but is morphologically similar to Laminaria saccharina. Carbon-metabolism processes (photosynthesis, respiration and light-independent carbon fixation) that are important in cold-adaptation will be identified in sporophytes of each species pair acclimated to the same temperature. Specific mechanisms of adaptation will be determined by comparing components of the photosynthetic apparatus as well as contents, activities and thermal properties of key enzymes involved in photosynthesis, respiration and light- independent carbon fixation. Comparisons of multiple species pairs and a broad suite of carbon-assimilation parameters will provide a comprehensive analysis of the mechanisms of low- temperature adaptation in algal species endemic to both the Arctic and Antarctic Oceans and increase an overall understanding of low temperature adaptation in all plants.