Hydrogen Peroxide Promotes Tomato Leaf Senescence by Regulating Antioxidant System and Hydrogen Sulfide Metabolism

Hydrogen peroxide (H O ) is relatively stable among ROS (reactive oxygen species) and could act as a signal in plant cells. In the present work, detached tomato leaves were treated with exogenous H O at 10 mmol/L for 8 h to study the mechanism of how H O regulates leaf senescence. The data indicated that H O treatment significantly accelerated the degradation of chlorophyll and led to the upregulation of the expression of leaf senescence-related genes ( , , , , and ) during leaf senescence. H O treatment also induced the accumulation of H O and malondialdehyde (MDA), decreased POD and SOD enzyme activities and inhibited H S production by reducing the expression of and A correlation analysis indicated that H O was significantly and negatively correlated with chlorophyll, the expression of leaf senescence-related genes, and and . The principal component analysis (PCA) results show that H S showed the highest load value followed by O , H O , , , etc. Therefore, these findings provide a basis for studying the role of H O in regulating detached tomato leaf senescence and demonstrated that H O plays a positive role in the senescence of detached leaves by repressing antioxidant enzymes and H S production.