The ongoing increases in greenhouse gases, such as CO₂, will affect plant in two principal ways. First, increased CO₂ will in itself entail adjustments in plant metabolism and physiology. Second, the resulting changes in climate are predicted to lead to increasingly intense periods of stressful conditions. Given their centrality to a myriad of plant functions, alterations in redox status are likely to be key to both these effects.

Through their influence on reversible modifications of protein Cys residues, thiol regulators, such as glutathione and thioredoxins, are key redox players. Both interact closely with reactive oxygen species (ROS) and, in recent years, ROS-triggered redox regulation has received intense interest. As by-products of numerous metabolic pathways, ROS are generated continuously in plant cells but their concentrations are modified by the environment, with accumulation being stimulated by stressful conditions. Further, they can also be pro-actively produced by the plant as a means of signalling the presence of invaders and/or to regulate phytohormone pathways.