Abiotic Stress Responses are Governed by Reactive Oxygen Species and Age

Abstract

Plants grown under abiotic stress conditions such as salinity, drought, cold, or heat display a variety of molecular, biochemical, and physiological changes including excessive generation of reactive oxygen species (ROS). The over‐production of ROS causes DNA damage and protein cross‐linking, which can lead to poor molecular transport, reduced enzyme activity, and loss of cell functions. The accumulation of ROS in response to stress also activates several signalling pathways which, in coordination with hormones such as ethylene and abscisic acid (ABA), allow for an adaptive response to stress, resulting in adjustments in plant growth and development in an attempt to maximise survival. Thus, the increase in ROS level by environmental stress results in both damage and an adaptive response; the outcome of the stress, i.e. survival or death then depends on the severity of the stress in combination with the stress response. In this article, we review elements of abiotic stress responses, in particular how ROS work together with the hormones ethylene and ABA to induce distinct stress responses in tissues of different age.