Effects of Oxidative Stress Caused by Oxygen and Hydrogen Peroxide on Energy Metabolism and Senescence in Oat Leaves

概要

論文の詳細を見る
In attached oat leaves the levels of adenine nucleotides decreased during leaf development and senescence. However, the energy charge (EC) only decreased from 0.90 in 4-cm leaves to 0.80 in senescent leaves. In detached leaves the levels of adenine nucleotides increased for 48 h, in association with an increase in RNase activity and a decrease in levels of RNA. The EC remained high until late senescence when levels of adenine nucleotides fell to about 30% of initial values. A decrease in energy parameters induced by transfer from light to darkness and from high (21%) to low (0.5% and anoxia) concentrations of oxygen resulted in an increase in membrane permeability. Oxidative stress (above 0.5% O_2) induced an increase in levels of malondialdehyde (MDA) and then in permeability, associated with a decrease in levels of adenine nucleotides. Oxidative stress provoked by 0.05 and 0.10 M H_2O_2 caused a more rapid decrease in energy parameters than O_2. Under oxidative stress (above 0.5% O_2) there is, first of all, an increase in membrane permeability and then a decrease in energy parameters, which in turn are involved with senescence via increases in oxidation of membranes and degradation of energy-producing systems.
日本植物生理学会の論文