A Study of Isoprene Emission from Plants

树木排放的异戊二烯是大气中碳氢化合物气体的重要来源。本项目将研究促进橡树异戊二烯排放的条件。这将有助于我们对大气的理解和预测大气变化的能力。异戊二烯被植物释放到大气中的速率是光合作用速率的2%或更多。植物释放的异戊二烯是生物圈和大气之间的重要界面；据估计，每年有350 X 1012克异戊二烯被释放到大气中。PI建议确定什么条件会加速完整叶片中异戊二烯的释放速度，并确定异戊二烯对植物生理的影响（如果有的话）。具体来说，他将测试(1)提出的异戊二烯释放与光呼吸的关系，(2)异戊二烯释放与光合作用的光反应的关系，以及(3)异戊二烯释放与光合碳代谢的关系。此外，还将进行实验以协助产生假设。实验将用完整的叶子进行。异戊二烯的形成可能涉及叶绿体内的糖酵解代谢，酪氨酸、色氨酸、亮氨酸、异亮氨酸和缬氨酸等人体营养必需氨基酸的合成也需要糖酵解代谢。还将对如何开始对叶绿体内异戊二烯合成和糖酵解反应进行生化研究进行初步研究。

Isoprene emission from trees is a significant source of hydrocarbon gases in the atmosphere. In this project the conditions which promote isoprene emission from oak trees will be investigated. This will contribute to our understanding of the atmosphere and our ability to predict changes in the atmosphere. Isoprene is released by plants to the atmosphere at a rate of 2% or more of the rate photosynthesis. This isoprene emission from plants is an important interface between the biosphere and the atmosphere; it is estimated that 350 X 1012 g of isoprene is released to the atmosphere each year. The PI proposes to determine what conditions accelerate the rate of isoprene emission from intact leaves and to determine what effects, if any, isoprene has on the physiology of plants. Specifically, he will test (1) the proposed relationship between isoprene emission and photorespiration, (2) the relationship between isoprene emission and the light reactions of photsynthesis, and (3) the relationship between isoprene emission and photosynthetic carbon metabolism. In addition experiments will be undertaken to assist in generating hypotheses. Experiments will be conducted with intact leaves. Isoprene formation is likely to involve glycolytic metabolism inside chloroplasts, which is also required for synthesis of tyrosine, tryptophan, leucine, isoleucine and valine, amino acids essential for human nutrition. Preliminary studies of how to begin biochemical studies of isoprene synthesis and glycolytic reactions inside chloroplasts will also be undertaken.