摘要
实验结果表明:照光时绿豆叶片分离线粒体通过细胞色素氧化酶途径的NADH氧化部分受阻,电子转向交替途径。不产生能量,不受能荷控制的NADH氧化途径有利于绿色细胞线粒体在光合作用时执行其提供碳架的功能。看来绿色细胞线粒体本身具有对光的敏感性,在照光时调节呼吸途径以适应其功能的转换。呼吸途径的转换机制目前还不清楚。绿豆种子线粒体与叶片线粒体不同,没有上述的这种对光的反应。
Oxygen consumption of mitochondria isolated from mung bean seeds and leaves was determined with an oxygen electrode in the dark or light. In mitochondria isolated from mung bean leaves, strong light (40 000 Ix) suppressed the NADH oxidation by 11. 8% through cytochrome pathway, and the capacity of the alternative pathway was increased by 71. 5 %. This suggested that illumination caused part of the electrons diverting from the cytochrome pathway to the alternative pathway. It was postulated that one of the physiological functions of the alternative pathway was to regulate the balance between levels of NADH and high-energy phosphate in green cells. The mechanism of this light effect on the change in respiratory pathway still remains unknown.
The mitochondria from germinated seeds of mung bean, however, were different to that from leaves of mung bean, it showed no response to light.
