Signalling and Antioxidant Defence Mechanisms in Higher Plants

Abstract

Major and rapid changes in environmental conditions can damage plant health and limit crop production. However, stress-sensing and subsequent regulation of the defence mechanisms in plants are poorly understood. The emphasis of this chapter will be to discuss: the evidence for the involvement of reactive oxygen species (ROS); the roles of the enzymatic and non-enzymatic ROS-scavenging and antioxidant systems; and avoidance mechanism of ROS production, during low-temperature and high light-induced oxidative stress. Furthermore the role of the redox status of the chloroplast will be discussed, particularly, quinone B and plastoquinone in regulation of expression of the nuclear- and the chloroplast-encoded genes that are necessarily for acclimatory processes.