Alteration of oxidative and carbohydrate metabolism under abiotic stress in two rice (Oryza sativa L.) genotypes contrasting in chilling tolerance.
Abiotic stress is a major limiting factor in crop production. Physiological comparisons between contrasting abiotic stress-tolerant genotypes will improve understanding of stress-tolerant mechanisms. Rice seedlings (S3 stage) of a chilling-tolerant (CT) genotype (CT6748-8-CA-17) and a chilling-sensitive (CS) genotype (INIAP12) were subjected to abiotic stresses including chilling (13/12 degrees C), salt (100mM NaCl), and osmotic (200mM mannitol). Measures of physiological response to the stresses included changes in stress-related sugars, oxidative products and protective enzymes, parameters that could be used as possible markers for selection of improved tolerant varieties. Metabolite analyses showed that the two genotypes responded differently to different stresses. Genotype survival under chilling-stress was as expected, however, CT was more sensitive to salt stress than the CS genotype. The CT genotype was able to maintain membrane integrity better than CS, perhaps by reduction of lipid peroxidation via increased levels of antioxidant enzymes during chilling stress. This genotype accumulated sugars in response to stress, but the accumulation was usually less than in the CS genotype. Chill-stressed CT accumulated galactose and raffinose whereas these saccharides declined in CS. On the other hand, the tolerance mechanism in the more salt- and water-deficit-tolerant CS may be associated with accumulation of osmoprotectants such as glucose, trehalose and mannitol.
Morsy
Mustafa R
MR
Department of Crop, Soil, and Environmental Sciences, PTSC 115, University of Arkansas, Fayetteville, AR 72701, USA.
Jouve
Laurent
L
Hausman
Jean-François
JF
Hoffmann
Lucien
L
Stewart
James McD
JM
D000222:Adaptation, Physiological / Q000235:genetics; D050260:Carbohydrate Metabolism; D003080:Cold Temperature; D005838:Genotype; D012275:Oryza / Q000235:genetics / Q000378:metabolism* / Q000502:physiology; D010084:Oxidation-Reduction; D017382:Reactive Oxygen Species / Q000378:metabolism; D012965:Sodium Chloride / Q000378:metabolism; D014867:Water / Q000502:physiology
D017382:Reactive Oxygen Species; D014867:Water; D012965:Sodium Chloride