Département de Biologie, Service de Radioagronomie, C.E.N. Cadarache, B.P. No. 1, 13115 Saint Paul lez Durance, France.
Plant Physiol. 1985 Jul;78(3):545-50. doi: 10.1104/pp.78.3.545.
With an experimental system developed for aquatic plants using the mass spectrometry technique and infrared gas analysis of CO(2), we studied the responses to various O(2) concentrations of gas exchanges with the red macroalga Chondrus crispus S. The results were as follows. (a) Irrespective of the CO(2) concentration, net photosynthesis was O(2) sensitive with a 45 to 70% stimulation at 2% O(2). Even with high CO(2), a significant Warburg effect was detected. (b) Although photosynthesis was CO(2) sensitive, O(2) photoconsumption was only weakly affected by CO(2) even at high CO(2) where it was still photodependent. (c) O(2) photoconsumption was always sensitive to O(2) concentration whatever the CO(2) concentration, but with O(2) exceeding 20% the kinetics disagreed with the Michaelis-Menten model, with saturation being reached more rapidly. With various CO(2) concentrations, the apparent K(m) (O(2)) ranged from 4 to 16% O(2) with a relatively constant V(max) (O(2)) of about one-third the V(max) (CO(2)). (d) Dark respiration seemed to be O(2) insensitive. These results are discussed in relation to the nature of the processes able to consume O(2) in the light, and seem to be consistent with a significant involvement of a Mehlertype reaction.
利用质谱技术和 CO2 的红外气体分析为水生植物开发了一个实验系统，我们研究了红色大型藻类角叉菜（Chondrus crispus S.）对各种 O2 浓度的气体交换的响应。结果如下。（a）无论 CO2 浓度如何，净光合作用对 O2 敏感，在 2% O2 下刺激 45%至 70%。即使在高 CO2 下，也检测到明显的 Warburg 效应。（b）尽管光合作用对 CO2 敏感，但 O2 光消耗仅受 CO2 弱影响，即使在高 CO2 下，它仍然是光依赖的。（c）无论 CO2 浓度如何，O2 光消耗总是对 O2 浓度敏感，但当 O2 超过 20%时，动力学与 Michaelis-Menten 模型不一致，达到饱和的速度更快。在不同的 CO2 浓度下，表观 K(m)（O2）范围为 4%至 16% O2，V(max)（O2）约为 V(max)（CO2）的三分之一，相对恒定。（d）暗呼吸似乎对 O2 不敏感。这些结果与能够在光下消耗 O2 的过程的性质有关，似乎与 Mehlertype 反应的显著参与一致。
