Photosynthesis: temperature responses and enzyme performance in C3 and C4 plants

自工业革命以来，大气中二氧化碳（CO2）水平的上升与上个世纪的气候变暖有关。 温度是严重影响光合作用的非生物因素之一，光合作用是植物收获阳光并将其用于将CO2固定为碳水化合物的过程。 在大多数情况下，我们对光合作用限制在最佳温度或低于最佳温度的原因有很好的理论理解，但关于为什么光合作用会在温暖但非致命的温度下下降，以及植物如何调整光合作用以适应不同的生长温度，存在相当多的科学争论。 这里提出的研究将使用各种实验方法来探索这些问题。 该研究计划还将直接研究Rubisco的功能，Rubisco是实际固定CO2的酶。 Rubisco是地球上最丰富的酶，但与其他酶相比，它是缓慢和低效的。 此外，其效率随着温度的升高而下降。 我将继续描述这种酶的生物化学和结构，以更好地了解它的性能，它是如何进化的，以及它对温度的反应。 了解光合作用对大气CO2和温度变化的反应是预测自然植物群落和农业物种对全球变化反应的重要组成部分。

Rising levels of atmospheric carbon-dioxide (CO2) since the industrial revolution have been linked to the climate warming of the last century. Temperature is one of the abiotic factors that severely impacts photosynthesis, the process by which plants harvest sunlight and use it to fix CO2 into carbohydrates. We have a good theoretical understanding of what limits photosynthesis at or below its optimum temperature in most cases, but there is considerable scientific debate about why photosynthesis declines in response to warm but non-lethal temperatures, and how plants adjust photosynthesis to different growth temperatures. The research proposed here will explore these questions using a variety of experimental approaches. The research program will also directly investigate the function of Rubisco, the enzyme that actually fixes CO2. Rubisco is the most abundant enzyme on Earth, but it is slow and inefficient in comparison to other enzymes. Moreover, its efficiency declines with increasing temperature. I will continue to characterize the biochemistry and structure of this enzyme, to better understand its performance, how it evolved, and how it responds to temperature. Understanding the response of photosynthesis to variation in atmospheric CO2 and temperature is a vital component of predicting the response of natural plant communities and agricultural species to global change.