Metabolic Regulation of Chloroplastic Respiration of Carbohydrates

碳水化合物叶绿体呼吸的代谢调节

• 批准号: 8703506
• 负责人: Martin Gibbs
• 金额: $ 18万
• 依托单位: Brandeis University
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 1987
• 资助国家: 美国
• 起止时间: 1987-07-15 至 1991-12-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=8703506&HistoricalAwards=false
• 关键词: Metabolic; Regulation; Chloroplastic; Respiration; Carbohydrates

The primary focus of this research is the retention of photosynthetic activity during extended photosynthesis and during dark intervals. The biological test materials are isolated spinach and Chlamydomonas chloroplasts and the parent tissues. The carbon dioxide fixing capability of the isolated intact spinach chloroplast falls off during photosynthesis after approximately 2-40 minutes, even though a functional electron transport chain and activity of stromal enzymes of the Calvin cycle are maintained. Chloroplasts kept in the dark for 10-20 minutes also lose their subsequent photosynthetic carbon dioxide fixing activity. Addition of a complex between magnesium ions and ATP or a chloroplastic respirable substrate to the external medium during photosynthesis or during the dark phase prior to photosynthesis allows retention of photosynthetic activity. Other nucleotides will not substitute for ATP nor do non-respirable chloroplastic substrates function in this capacity. Similarly, pre-treatment of the darkended spinach leaf results in an inactivation of the carbon dioxide fixing capacity. The level of inactivation seems to depend upon the nutritional status (perhaps carbohydrate content) of the leaf. Inactivation is extremely pH dependent as is senescence of the chloroplast. The basic events that result in the loss of photosynthetic carbon dioxide fixation will be elucidated as well as the underlying principles of the protective mechanisms. This research should provide substantial information supporting the concept that the retention of chloroplastic carbon dioxide fixing activity is dependent upon extrachloroplastic events such as cellular respiration and, to a limited extent, on chloroplastic respiration. Separation of the chloroplast from these events leads to its rapid irreversible destruction unless the organelle is protected by the products of respiration generated in the mitochondrion or within the organelle by starch break-down. The linkage of chloroplastic competency with other cellular events will add a basic component to our understanding of stress physiology, i.e. water status, temperature, ionic balance and other factors.

这项研究的主要重点是保留 在延长的光合作用期间的光合活性， 在黑暗的间隔。 生物试验材料为 分离的菠菜和衣原体叶绿体和亲本 组织中 分离菌株的二氧化碳固定能力 完整菠菜叶绿体福尔斯在光合作用期间脱落 大约2-40分钟后，即使功能性的 电子传递链和基质酶的活性 保持卡尔文循环。 叶绿体在黑暗中保存 10-20分钟也失去了它们随后的光合作用碳 二氧化物固定活性 添加复合物， 镁离子和ATP或叶绿体可呼吸底物 在光合作用期间或在黑暗中， 光合作用之前的阶段允许保留 光合活性 其他核苷酸不会取代 对于ATP，非呼吸性叶绿体基质也不起作用， 以这种身份。 同样，对黑暗的人进行预处理 菠菜叶导致二氧化碳失活 固定能力 失活的程度似乎取决于 根据营养状况（可能是碳水化合物含量）， 叶子 灭活与pH值密切相关， 叶绿体的衰老。 导致 光合作用二氧化碳固定的损失将是 的基本原则， 保护机制。 这项研究应该提供大量的信息 支持了叶绿体的保留 二氧化碳固定活性取决于 细胞呼吸等叶绿体外事件， 对叶绿体呼吸作用的影响有限。 分离 叶绿体从这些事件导致其快速 不可逆转的破坏，除非细胞器受到保护， 呼吸作用的产物产生于呼吸道，或 在细胞器内通过淀粉分解。 联动 叶绿体与其他细胞事件的能力将增加一个 我们对压力生理学的理解的基本组成部分，即 水分状况、温度、离子平衡等因素。