088 Improving cryopreservation potential with antioxidant treatments

Abstract

Most plants can now be cryopreserved using one of several protocols, providing a stable, long-term and low-cost backup for clonally propagated plants. However, some plants respond poorly to cryopreservation due to lack of tolerance to low temperatures or osmotic and chemical stress. Low temperatures cause chilling and freezing injury and these sub-lethal changes can lead to increased production of free radical species and cellular damage. Abiotic stresses resulting from low temperature, water deficit or nutrient deprivation can also increase reactive oxygen species (ROS) formation to toxic levels in cells and tissues. In addition, cryopreservation protocols increase oxidative stress through osmotic and chemical treatments that are required for the vitrification process. ROS include superoxide radicals, hydroxyl radicals, hydrogen peroxide and singlet oxygen. Natural antioxidant defense mechanisms evolved in plants to combat the effects of physiological stress. These ROS scavenging mechanisms include increased production of antioxidant enzymes such as superoxide dismutase, peroxidases, mono- and dehydroascorbate reductase, glutathione reductase and catalase. The addition of these types of antioxidants during the cryopreservation process reduces several types of cellular oxidation and results in improved regrowth of both control and cryopreserved plant tissues. Source of funding: US Department of Agriculture. Conflict of interest: None declared. Barbara.Reed@ars.usda.gov