title: Wheat cultivars differing in heat tolerance show a differential response to oxidative stress during monocarpic senescence under high temperature stress.
abstract: Wheat crop may experience heat stress during post-anthesis phase associated with oxidative stress, enhanced senescence, and reduced productivity. Stay green is a desirable character for the selection for heat tolerance in wheat. In the present study, antioxidant metabolism was studied under post-anthesis heat stress in field during monocarpic senescence by comparing two wheat genotypes, namely Hindi62 (heat tolerant and delayed senescent) and PBW343 (heat susceptible and early senescent). Hindi62 exhibited lesser oxidative stress, membrane damage, and coordinated antioxidant defense as compared to PBW343 under heat stress during post-anthesis stage. Higher activity of SOD, CAT, APX, GR, and MDHAR under heat stress contributed towards delayed senescence in Hindi62 compared to PBW343. GSH/GSSG ratio was also maintained at higher level in Hindi62 under heat stress compared to PBW343 during senescence. Hence, the present study clearly shows that upregulated level of the total antioxidant capacity during grain development contributed towards delayed senescence and heat tolerance in Hindi62 compared to the heat-susceptible PBW343.
authors.affiliation: Stress Physiology Lab., Water Technology Center, Indian Agricultural Research Institute, New Delhi, 110012, India, renu_wtc@rediffmail.com.
authors.forename: Renu
authors.initials: R
authors.lastname: Khanna-Chopra
authors.forename: Shakti
authors.initials: S
authors.lastname: Chauhan
mesh_terms: D000222:Adaptation, Physiological; D060387:Ascorbate Peroxidases / Q000378:metabolism; D001205:Ascorbic Acid / Q000378:metabolism; D002374:Catalase / Q000378:metabolism; D005978:Glutathione / Q000378:metabolism; D005980:Glutathione Reductase / Q000378:metabolism; D018869:Heat-Shock Response; D006861:Hydrogen Peroxide / Q000378:metabolism; D015227:Lipid Peroxidation; D008315:Malondialdehyde / Q000378:metabolism; D018384:Oxidative Stress; D057445:Plant Dormancy; D010940:Plant Proteins / Q000378:metabolism; D013482:Superoxide Dismutase / Q000378:metabolism; D014908:Triticum / Q000502:physiology*
chemical_list: D010940:Plant Proteins; D008315:Malondialdehyde; D006861:Hydrogen Peroxide; D060387:Ascorbate Peroxidases; D002374:Catalase; D013482:Superoxide Dismutase; D005980:Glutathione Reductase; D005978:Glutathione; D001205:Ascorbic Acid