Department of Biology, Brookhaven National Laboratory, Upton, New York 11973.
Plant Physiol. 1977 Oct;60(4):538-42. doi: 10.1104/pp.60.4.538.
Anaerobiosis depresses the light- and bicarbonate-saturated rates of O(2) evolution in intact spinach (Spinacia oleracea) chloroplasts by as much as 3-fold from those observed under aerobic conditions. These lower rates are accelerated 2-fold or more by the addition of 1 mum antimycin A or by low concentrations of the uncouplers 0.3 mm NH(4)Cl or 0.25 mum carbonyl cyanide m-chlorophenylhydrazone. Oxaloacetate and glycerate 3-phosphate reduction rates are also increased by antimycin A or an uncoupler under anaerobic conditions. At intermediate light intensities, the rate accelerations by either antimycin A or uncoupler are inversely proportional to the adenosine 5'-triphosphate demand of the reduction process for the acceptors HCO(3) (-), glycerate 3-phosphate, and oxaloacetate. The acceleration of bicarbonate-supported O(2) evolution may also be produced by adding an adenosine 5'-triphosphate sink (ribose 5-phosphate) to anaerobic chloroplasts. The above results suggest that a proton gradient back pressure resulting from antimycin A-sensitive cyclic electron flow is responsible for the depression of light-saturated photosynthesis under anaerobiosis.
厌氧条件下，完整菠菜叶绿体（Spinacia oleracea）中 O(2) 释放的光饱和和碳酸氢盐饱和速率比有氧条件下观察到的速率降低了多达 3 倍。添加 1 mum 安密妥菌素 A 或低浓度的解偶联剂 0.3 mm NH(4)Cl 或 0.25 mum 羰基氰化物 m-氯代苯腙，可使这些较低的速率加速 2 倍或更多。厌氧条件下，草酰乙酸和甘油酸 3-磷酸还原速率也会因安密妥菌素 A 或解偶联剂而增加。在中等光强下，安密妥菌素 A 或解偶联剂引起的速率加速与还原过程对接受体 HCO(3) (-)、甘油酸 3-磷酸和草酰乙酸的腺苷 5'-三磷酸需求成反比。添加腺苷 5'-三磷酸汇（核糖 5-磷酸）也可以促进碳酸氢盐支持的 O(2) 释放的加速。上述结果表明，安密妥菌素 A 敏感的环式电子流产生的质子梯度背压是厌氧条件下光饱和光合作用受到抑制的原因。
