The Mechanism and Magnitude of the Direct Effect of CO2 on Apparent Leaf Respiration in Diverse Plant Species

由于包括化石燃料组合和森林燃烧在内的人类活动，大气中二氧化碳（CO2）的浓度目前高于有记录的历史水平，并以前所未有的速度上升。二氧化碳是几种“温室气体”之一，其浓度的迅速增加可能导致全球气候变暖。植被在全球二氧化碳循环中扮演着重要的角色，它在光合作用过程中从大气中吸收二氧化碳，在呼吸过程中向大气中释放二氧化碳。全球光合作用或呼吸作用的任何变化都会影响大气CO2浓度的变化率。最近的研究表明，植物呼吸可能在短期内受到二氧化碳浓度增加的抑制，但实际上对潜在的生理机制、反应的持续时间或这种现象在自然界中的普遍程度一无所知。提出的研究将在实验室和自然环境中结合使用新颖的实验方法，开始对二氧化碳对呼吸直接影响的生化和生理基础进行检查。该研究将显著促进对二氧化碳对植物呼吸调节的认识。反过来，这将提高我们对植被在调节大气二氧化碳浓度中的作用的理解，从而提高对全球气候变化潜力的理解。

As a result of human activities including fossil fuel combination and forest burning, the concentration of atmospheric carbon dioxide (CO2) is currently higher than in recorded history and it is rising at an unprecedented rate. CO2 is one of the several `greenhouse gases` and the rapid increase in its concentration may lead to global climatic warming. Vegetation plays a large role in the global CO2 cycle-it removes CO2 from the atmosphere in the process of photosynthesis and releases CO2 to the atmosphere in the process of respiration. Any changes in global photosynthesis or respiration will affect the rate of change of atmospheric CO2 concentration. Recent studies indicate that plant respiration may be inhibited in the short-term by increased CO2 concentration, yet virtually nothing is known of the underlying physiological mechanism(s), the duration of the response, or how widespread this phenomenon is in nature. The proposed research initiates an examination of the biochemical and physiological basis of the direct effect of CO2 on respiration using a combination of novel experimental approaches in both laboratory and natural settings. The research should significantly advance knowledge of the regulation of plant respiration by CO2. In turn, this will improve our understanding of the role of vegetation in regulating atmospheric CO2 concentration and, thus, the potential for global climate change.