Limitation of Photosynthesis by Carbon Metabolism

作者：Mark Stitt · 发表于：PLANT PHYSIOLOGY · 年份：1986 · DOI：10.1104/pp.81.4.1115 · 被引用次数：276 · 研究领域：Photosynthetic Processes and Mechanisms

It has been investigated how far electron transport or carbon metabolism limit the maximal rates of photosynthesis achieved by spinach leaves in saturating light and CO(2). Leaf discs were illuminated with high light until a steady state rate of O(2) evolution was attained, and then subjected to a 30 second interruption in low light, to generate an increased demand for the products of electron transport. Upon returning to high light there is a temporary enhancement of photosynthesis which lasts 15 to 30 seconds, and can be up to 50% above the steady state rate of O(2) evolution. This temporary enhancement is only found when saturating light intensities are used for the steady state illumination, is increased when low light rather than darkness is used during the interruption, and is maximal following a 30 to 60 seconds interruption in low light. Decreasing the temperature over the 10 to 30 degrees C range led to the transient enhancement becoming larger. The temporary enhancement is associated with an increased ATP/ADP ratio, a decreased level of 3-phosphoglycerate, and increased levels of triose phosphate and ribulose 1,5-bisphosphate. Since electron transport can occur at higher rates than in steady state conditions, and generate a higher energy status, it is concluded that leaves have a surplus electron transport capacity in saturating light and CO(2). From the alterations of metabolites, it can be calculated that the enhanced O(2) evolution must be accompanied by an incre...