Photosynthesis: Metabolic Transport and Cold Lability of Photosynthetic Enzymes

光合作用作为一个生物过程具有根本的重要性，了解其机制以及受植物和环境因素的控制是很重要的。植物从大气中吸收二氧化碳，并将其同化为用于合成淀粉，蔗糖，氨基酸等的有机磷酸盐。少数高等植物，包括玉米（玉米），已经进化出一种将二氧化碳集中在叶片中的机制，因此空气中的低浓度（0.034%）不会限制它们进行光合作用的能力。这种机制涉及一种称为C.4循环的生化途径，这种植物被称为C.4植物。C.. 4种植物在高温和高光强下实现非常高的光合速率。然而，在许多C.4植物中，光合作用对中等低温（即10至15 ℃）相当敏感，而少数物种或种族则更耐受。在本项目中，将检查与C.4循环（有机化合物的运输和蛋白质作为反应催化剂的功能）相关的过程对低温的敏感性。将在耐冷的C.4植物中检查在低温下保护过程的因素。从这些研究中获得的基本知识将有助于开发C.4光合作用的机制，使其能够更大规模地用于食品生产、生物质生产和城市应用。

Photosynthesis is of fundamental importance as a biological process and it is important to understand its mechanism, and control by factors within the plant and in the environment. Plants take up carbon dioxide from the atmosphere and assimilate it into organic phosphates which are used for synthesizing starch, sucrose, amino acids, etc. A limited number of higher plants, including maize (corn), have evolved a mechanism for concentrating carbon dioxide in their leaves so that the low concentration in the air (0.034%) does not limit their ability to perform photosynthesis. This mechanism involves a biochemical pathway called the C.4 cycle, and such plants are called C.4 plants. C..4 plants achieve very high rates of photosynthesis under high temperature and light intensities. However, in many C.4 plants, photosynthesis is quite sensitive to moderately low temperatures (i.e. 10 to 15.oC while a few species or races are more tolerant. In this project, sensitivity to low temperature will be examined relative to processes associated with the C.4 cycle (transport of organic compounds and function of proteins as catalysts of reactions). Factors which protect the processes under low temperatures will be examined in C.4 plants which are chilling tolerant. Basic knowledge gained from these studies will be of value in exploiting the mechanism of C.4 photosythesis so that it can be used on a larger scale in production of food, biomass and in urban applications.