title: Ascorbate-glutathione cycle of mitochondria in osmoprimed soybean cotyledons in response to imbibitional chilling injury.
abstract: Osmopriming treatment of chilling-sensitive soybean (Glycine max L. cv. Zhonghuang-22) seeds for 72h at 25°C with polyethylene glycol (PEG8000) solution at -1.5MPa strongly improves chilling resistance. The aim of the present work was to investigate whether the beneficial effect of osmopriming is associated with restoration of the ascorbate-glutathione (ASC-GSH) cycle of mitochondria in soybean seeds. Compared with the control, both H(2)O(2) and malondialdehyde (MDA) contents in mitochondria of osmoprimed seeds decreased after chilling treatment, and these changes were associated with increased activities of superoxide dismutase (SOD), ascorbate peroxidase (APX), glutathione reductase (GR), monodehydroascorbate reductase (MDHAR) and L-galactono-γ-lactone dehydrogenase (GLDH). However, the activity of dehydroascorbate reductase (DHAR) showed no obvious change during osmopriming treatment. Increased ASC and GSH contents accompanied prolonged osmopriming, and the reduced/oxidized ratios of ASC and GSH increased differently during osmopriming. These results indicate that osmopriming treatment enhances activity of the ASC-GSH cycle of mitochondria, which raises the chilling tolerance in soybean seeds and protects against H(2)O(2) that is generated in mitochondria during imbibition at low temperature.
authors.affiliation: Key Laboratory for Genetics and Breeding in Forest Trees and Ornamental Plants, Ministry of Education, Beijing Forestry University, Beijing 100083, China.
authors.forename: Haiping
authors.initials: H
authors.lastname: Sun
authors.forename: Lin
authors.initials: L
authors.lastname: Li
authors.forename: Xu
authors.initials: X
authors.lastname: Wang
authors.forename: Sen
authors.initials: S
authors.lastname: Wu
authors.forename: Xiaofeng
authors.initials: X
authors.lastname: Wang
mesh_terms: D001205:Ascorbic Acid / Q000378:metabolism*; D003080:Cold Temperature; D018548:Cotyledon / Q000378:metabolism*; D018525:Germination / Q000502:physiology; D005978:Glutathione / Q000378:metabolism*; D006861:Hydrogen Peroxide / Q000378:metabolism; D015227:Lipid Peroxidation; D008928:Mitochondria / Q000378:metabolism*; D013025:Glycine max / Q000378:metabolism*
chemical_list: D006861:Hydrogen Peroxide; D005978:Glutathione; D001205:Ascorbic Acid