Response of thylakoid bound ascorbate peroxidase under abiotic stress in two wheat genpotypes

摘要

Environmental stresses disrupt photosynthesis and increase photorespiration, altering the normal homeostasis of cells and cause an increased production of reactive oxygen species (Miller et ah, 2010). Reactive oxygen species (ROS) such as 02, H202, 02and HO, are toxic molecules capable of causing oxidative damage to proteins, DNA and lipids (Apel and Hirt, 2004). On the other hand, transient increases in ROS levels also have a vital rple in stress signaling and thereby in the survival of plants underadverse environmental conditions (Dat et at., 2000) . Both biotic and abiotic stresses usually lead to an enhanced ROS production; therefore ROS-scavenging mechanisms acting in different organelles play a major role in plant survival and productivity, particularly in extreme environments (Danna et at., 2003). In plants, ROS levels are controlled via a versatile antioxidant network. Components of the antioxidant system reside in various cellular locations and include a range of enzymatic scavengers, such as superoxide dismutases (SODs), ascorbate peroxidases (APXs), peroxiredoxins (PRXs), glutaredoxins, glutathione peroxidases and catalases. In addition, several non-enzymatic antioxidants such as ascorbate, glutathione, tocopherols, carotenoids and phenolic compounds also contribute to the cellular redox balance (Mitler et al., 2004).