Photoprotection During Winter Stress

冬季应激期间的光保护

• 批准号: 9631064
• 负责人: William Adams
• 金额: $ 20.05万
• 依托单位: University of Colorado at Boulder
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 1996
• 资助国家: 美国
• 起止时间: 1996-08-01 至 1999-07-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=9631064&HistoricalAwards=false
• 关键词: Photoprotection; During; Winter; Stress

9631064 Adams The proposed studies will examine the low temperature acclimation of a photoprotective process facilitating the harmless dissipation of excess excitation energy in plants that retain leaves during the winter. Excess excitation energy can be removed directly within the chlorophyll/carotenoid-binding pigment complexes in a process requiring the carotenoid zeaxanthin and a low pH within the chloroplast membrane. On warm days, under otherwise favorable conditions, zeaxanthin accumulates during midday when light is excessive and is reconverted to its precursor by the end of the day as light levels become nonexcessive. During the winter large amounts of zeaxanthin can be retained throughout cold nights, ready to become engaged in energy dissipation the instant chlorophyll absorbs light in the morning. In the proposed studies the mechanisms underlying the nocturnal retention of this pigment, and its continued engagement for energy dissipation, will be examined. The first mechanism involves the hypothesized maintenance of a pH gradient across the photosynthetic membrane of leaves exposed to winter conditions which results in the sustained engagement of zeaxanthin in energy dissipation, primarily in the minor, proximal chlorophyll-binding proteins. The second mechanism to be tested involves the hypothesized synthesis of zeaxanthin from beta-carotene in the core antenna proteins that may accompany acclimation to the conditions of excess light during the winter. To test this hypothesis the carotenoid composition of specific chloroplast proteins will be determined from leaves acclimated to favorable temperatures in the summer as well as low temperatures in the winter. Ultimately the information gleaned through these studies may prove useful in improving the tolerance of agricultural species planted in areas th at experience lower temperatures than those experienced by the plants during their evolutionary history.

9631064亚当斯 拟议的研究将检查低温驯化， 一 光保护 过程促进 的 在冬季保留叶子的植物中多余的激发能量的无害耗散。 可以去除多余的激发能 直接 内 叶绿素/类胡萝卜素结合色素 在一个过程中， 的 类胡萝卜素玉米黄质和叶绿体膜内的低pH。在温暖的日子里， 下 否则 有利 条件， 玉米黄质在中午光线充足时积累， 在一天结束的时候，当光照水平变得不过度时，它会重新转化为它的前体。 在冬季大量的玉米黄质可以保留在整个寒冷的夜晚，准备成为从事能量耗散的瞬间叶绿素吸收光在早上。 在拟议的研究中，将研究这种色素夜间保留的机制及其持续参与能量耗散的机制。 的 第一种机制涉及 假设在冬季条件下，叶片光合膜上的pH梯度维持不变， 玉米黄质在能量中的作用 耗散，主要是在次要的，近端叶绿素结合蛋白。 第二个机制进行测试涉及假设的合成玉米黄质从β-胡萝卜素的核心天线蛋白，可能伴随着驯化的条件下，多余的光在冬季。 为了验证这一假设，将从适应夏季有利温度以及冬季低温的叶片中确定特定叶绿体蛋白质的类胡萝卜素组成。 最终，通过这些研究收集到的信息可能有助于提高种植在温度低于植物进化历史中所经历的温度的地区的农业物种的耐受性。