景天酸代谢植物光照后二氧化碳的爆发
Postillumination burst of carbon dioxide in crassalacean Acid metabolism plants.
作者信息
Crews C E, Vines H M, Black C C
机构信息
Departments of Horticulture and of Botany, University of Georgia, Athens, Georgia 30602.
出版信息
Plant Physiol. 1975 Apr;55(4):652-7. doi: 10.1104/pp.55.4.652.
Immediately following exposure to light, a postillumination burst of CO(2) has been detected in Crassulacean acid metabolism plants. A detailed study with pineapple (Ananas comosus) leaves indicates that the postillumination burst changes its amplitude and kinetics during the course of a day. In air, the postillumination burst in pineapple leaves generally is exhibited as two peaks. The postillumination burst is sensitive to atmospheric CO(2) and O(2) concentrations as well as to the light intensity under which plants are grown. We propose that the CO(2) released in the first postillumination burst peak is indicative of photorespiration since it is sensitive to either O(2) or CO(2) concentration while the second CO(2) evolution peak is likely due to decarboxylation of organic acids involved in Crassulacean acid metabolism.In marked contrast to other higher plants, the postillumination burst in Crassulacean acid metabolism plants can be equal to or greater than the rate of photosynthesis. Photosynthesis in pineapple leaves also varies throughout a day. Both photosynthesis and the postillumination burst have a daily variation which apparently is a complex function of degree of leaf acidity, growth light intensity, ambient gas phase, and the time a plant has been exposed to a given gas.
在景天酸代谢植物中，光照后立即检测到了光照后二氧化碳的释放。对菠萝（Ananas comosus）叶片的详细研究表明，光照后二氧化碳的释放量在一天中会发生幅度和动力学变化。在空气中，菠萝叶片的光照后二氧化碳释放通常表现为两个峰值。光照后二氧化碳的释放对大气中二氧化碳和氧气的浓度以及植物生长时的光照强度敏感。我们认为，光照后第一个二氧化碳释放峰值所释放的二氧化碳表明存在光呼吸作用，因为它对氧气或二氧化碳浓度敏感，而第二个二氧化碳释放峰值可能是由于参与景天酸代谢的有机酸脱羧所致。与其他高等植物形成显著对比的是，景天酸代谢植物的光照后二氧化碳释放量可能等于或大于光合作用速率。菠萝叶片的光合作用在一天中也会变化。光合作用和光照后二氧化碳的释放都有日变化，这显然是叶片酸度、生长光照强度、周围气相以及植物暴露于给定气体的时间等多种因素的复杂函数。
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