Location: National Clonal Germplasm RepositoryTitle: Improving cryopreservation potential with antioxidant treatments) Author
Submitted to: Cryobiology
Publication Type: Abstract only
Publication Acceptance Date: 6/5/2013
Publication Date: 12/15/2013
Citation: Reed, B.M. 2013. Improving cryopreservation potential with antioxidant treatments. [Abstract] Cryobiology. Pg. 53. Interpretive Summary: 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.The development of effective protocols for cryopreserving vegetatively propagated plants in liquid nitrogen is important for the long-term conservation of many horticultural crops as well as endangered species. Protocols are already in place for many plant species and provide a low cost, long-term backup safe from diseases or environmental damage. Some plants can not be cryopreserved due to lack of tolerance to low temperatures or water stress. Low temperatures, drought or lack of nutrients can also cause injury. Plants have evolved natural defense mechanisms to combat the effects of stress. The steps in cryopreservation protocols designed to preserve the plants also impose a series of stresses to condition them to survive freezing. A number of recent studies show that the addition of antioxidants during the cryopreservation process reduces oxidation and improves recovery of cryopreserved plant tissues.
Technical 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 induced ROS. 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.