Chapter 12 - Physiological roles of hydrogen sulfide under heavy metal stress

Abstract

Hydrogen sulfide (H2S) having a characteristic odor has been known for centuries as a toxic gas for animals and human, particularly at a higher dose. It has been showed that higher amount of exogenous H2S also can be phytotoxic, making disorders of the development but a lower concentration of this gas may have beneficial effects on plants and can improve their stress tolerance against various abiotic stress factors such as salinity, drought, heat or heavy metal stress. Recent studies support that this induced stress tolerance is probably due to the activation of the antioxidant system triggered by H2S. This chapter gives an overview of physiological roles of endogenous H2S, its interactions with other signal molecules (e.g. NO), and the potentially positive effects of exogenous H2S application on plants under metallic stress.