Lehrstuhl für Pflanzenphysiologie der Universität Bayreuth, West Germany.
Plant Physiol. 1977 Dec;60(6):903-6. doi: 10.1104/pp.60.6.903.
The O(2) concentration in intact and osmotically disrupted isolated spinach (Spinacia oleracea, L.) chloroplasts during photosynthesis was estimated. The chloroplasts were allowed to reduce 3-phosphoglycerate, CO(2), or ferricyanide in light until the rate of O(2) production was linear. When the light was turned off O(2) evolution from the chloroplasts continued for a few seconds. This prolonged O(2) evolution is due to an O(2) surplus inside the chloroplasts which equilibrates with that in the medium. From this surplus the O(2) concentration inside the chloroplasts at the moment when the light had been switched off was calculated. In all experiments the O(2) concentration inside the photosynthesizing chloroplasts was higher than that outside, but was dependent upon the O(2) concentration of the chloroplast medium. At low external O(2) concentration (30 mum) the ratio of the internal to the external O(2) concentration was about 5, whereas at concentrations corresponding to those in airsaturated water this ratio was close to 1. With osmotically broken chloroplasts this ratio was 1.2 at 30 mum O(2) and almost 1 from 150 mum onward. When the O(2) surplus found in broken chloroplasts during photosynthesis was related to the volume of the thylakoids, a ratio of about 2.3 was observed.
测定了光合作用过程中完整和渗透压破坏的分离菠菜（Spinacia oleracea，L.）叶绿体中的 O(2)浓度。在光下允许叶绿体还原 3-磷酸甘油酸、CO(2)或铁氰化物，直到 O(2)产生速率呈线性。当光关闭时，叶绿体中的 O(2) 释放会持续几秒钟。这种延长的 O(2)释放是由于叶绿体内部存在 O(2)过剩，与介质中的 O(2)平衡。根据这个过剩量，计算出光关闭时叶绿体内部的 O(2)浓度。在所有实验中，光合作用叶绿体内部的 O(2)浓度都高于外部，但取决于叶绿体介质中的 O(2)浓度。在低外部 O(2)浓度（30 mum）下，内部与外部 O(2)浓度的比值约为 5，而在与空气饱和水中的浓度相对应的浓度下，该比值接近 1。对于渗透压破坏的叶绿体，在 30 mum O(2)下该比值为 1.2，从 150 mum 开始几乎为 1。当光合作用过程中破碎叶绿体中的 O(2)过剩与类囊体的体积相关时，观察到约 2.3 的比值。
