Non-Methane Hydrocarbon Emissions from Plants

非甲烷碳氢化合物（NMHC）的排放量 二十多年前就知道天然来源。 主要 被认为是植物的来源。 其他重大自然灾害 来源是海洋藻类，土壤中的微生物活动，天然 气体渗出，生物质燃烧。 天然烃排放 植物中的蛋白质在产生中发挥着重要作用 对流层中的光化学氧化剂，但有一个 区域和全球库存中的不确定性数量 这些生物化合物。 许多不确定性产生于 因为缺乏有关碳氢化合物的精确数据 关键环境变量的影响， 植被的排放。 此外，还有不确定性 关于大部分的化学鉴定 生物碳氢化合物，很少有人知道的 植物碳氢化合物生产的生理学或生物化学。 该项目将进行实验室研究，以a）测量 准确地控制环境变量 植物中异戊二烯和相关NMHC的生物发生，B）提供 新的，化学鉴定排放的NMHC，和c）探索 微生物在叶子表面的作用， NMHC的来源。 非甲烷碳氢化合物排放从工厂在环境 受控气体交换室的特征是气体 色谱测量，并识别 通过气相色谱/质谱法测定碳氢化合物。 通过 使用代表主要植物群和生态系统的植物， NMHC排放将与空气温度、光照 强度、湿度和二氧化碳浓度，以及 将排放与这些参数相关联的算法将是 开发 将开发一个模型来解释如何以及为什么 植物排放异戊二烯和相关的NMHC，并建议 对这些排放物的环境监管。

The emission of non-methane hydrocarbons (NMHC) from natural sources has been known for over two decades. The major source is thought to be vegetation. Other significant natural sources are marine algae, microbial activity in soils, natural gas seeps, the biomass burning. Natural hydrocarbon emissions from plants play an important role in the generation of photochemical oxidants in the troposphere, but there are a number of uncertainties in regional and global inventories of these biogenic compounds. Much of the uncertainty arises because there is a lack of precise data relating hydrocarbon emissions to key environmental variables that regulate such emissions from vegetation. In addition, there is uncertainty about the chemical identification of a large fraction of biogenic hydrocarbons, and very little is known of the physiology or biochemistry of plant hydrocarbon production. This project will conduct laboratory studies to a) measure accurately the environmental variables controlling the biogenesis of isoprene and related NMHC in plants, b) provide new, chemical identification of emitted NMHC, and c) explore the role of micro organisms on leaf surfaces as sinks or sources of NMHC. NMHC emissions form plants in environmentally controlled gas exchange chambers will be characterized by gas chromatography measurements, with identification of hydrocarbons by gas chromatography/mass spectrometry. By using plants representing major plant groups and ecosystems, NMHC emissions will be related to air temperature, light intensity, humidity, and carbon dioxide concentration, and algorithms relating emissions to these parameters will be developed. A model will be developed to explain how and why plants emit isoprene and related NMHC, and to suggest the environmental regulation of such emissions.