Osmolytes and metal ions accumulation, oxidative stress and antioxidant enzymes activity as determinants of salinity stress tolerance in maize genotypes

• Published in: Acta physiologiae plantarum Vol. 32; no. 3; pp. 477 - 486
• Main Authors: Kholova, Jana, Sairam, Raj Kumar, Meena, Ramesh C
• Format: Journal Article
• Language: English
• Published: Berlin/Heidelberg Berlin/Heidelberg : Springer-Verlag 2010; Springer-Verlag
• Subjects: Agriculture; Biomedical and Life Sciences; Life Sciences; Original Paper; Plant Anatomy/Development; Plant Biochemistry; Plant Genetics and Genomics; Plant Pathology; Plant Physiology; Oxidative stress; Calcium; Sodium; Antioxidant enzymes; Potassium; Osmolytes; Salinity
• ISSN: 0137-5881; 1861-1664
• DOI: 10.1007/s11738-009-0424-y

Effect of soil salinity was studied in two maize (Zea mays L.) genotypes, DTP-w-c 9 (comparatively tolerant) and Prabhat (susceptible) under control and three levels of salinity at vegetative and anthesis stages during summer-rainy season. Salinity stress decreased relative water content (RWC), chlorophyll (Chl) and carotenoid (Car) contents, membrane stability index (MSI), potassium (K⁺) and calcium (Ca²⁺) contents, and increased the rate of superoxide radical (O ₂ ·⁻ ) production, contents of hydrogen peroxide (H₂O₂), thiobarbituric acid reactive substances (TBARS) (measure of lipid peroxidation), proline, glycine-betaine, total soluble sugars, sodium (Na⁺), and Na⁺/K⁺ and Na⁺/Ca²⁺ ratios in both the genotypes. Activities of superoxide dismutase (SOD), ascorbate peroxidase (APX), catalase (CAT) and glutathione reductase (GR) increased up to S₂ salinity level in both the genotypes, and up to highest salinity level (S₃) in DTP-w-c 9 at the two stages. Salinity-induced decrease in RWC, Chl, Car, MSI, K⁺ and Ca²⁺ was significantly greater in Prabhat, which also recorded higher Na⁺ content and Na⁺/K⁺ and Na⁺/Ca²⁺ ratios than DTP-w-c 9. DTP-w-c 9 recorded higher contents of proline, glycine-betaine, total soluble sugars, K⁺, Ca²⁺, activity of SOD, APX, CAT, GR, and comparatively lower O ₂ ·⁻ , H₂O₂ and TBARS contents compared to Prabhat. Results show that salinity tolerance of DTP-w-c 9, as manifested by less decrease in RWC, Chl, Car and MSI, is associated with maintenance of adequate levels of K⁺ and Ca²⁺, greater contents of osmolytes, higher antioxidant enzymes activity, and lower O ₂ ·⁻ , H₂O₂, TBARS and Na⁺ contents than Prabhat.