The effect of illumination and oxygen concentration on respiration and metabolites content in pea leaves

摘要

The leaves and mesophyll protoplasts of pea did not show the light-enhanced dark respiration (LEDR) when the O_2 concentration during the period of illumination was low. The rate of glycine oxidation by mitochondria from illuminated leaves was twicehigher as that from darkened leaves. Illumination had no effect on malate oxidation. The content of glycine and serine was markedly higher in mitochondria of leaves illuminated than darkened. Independently of the CO_2 concentration in the air (21 percentO_2) the ATP/ADP ratio in illuminated leaves was significantly higher than in that illuminated at low O_2(1 percent). Presented results suggest that both the tricarboxylic acid cycle and the electron transport chain are capable of operation with the rate higher in leaves illuminated at 21 percent O_2 than at 1 percent O_2 or in the darkened.