Author: Alabi Ogechi Angela
Department: Applied Biochemistry
Affiliation: Nnamdi Azikiwe University Awka
Salinity is one of the world’s oldest and most widely distributed environmental challenges. Excessive salts in soil affect all major living processes such as growth, photosynthesis, protein, and lipid metabolism. Considering the fact that maize is the third most important cereal crop in the world, after wheat and rice, and is grown all over the world under different climatic condition, this research monitored changes in physical and biochemical parameters associated with salt tolerance in three varieties of maize. The physical parameters reduced in all the three varieties of maize (western white agric maize, western yellow agric maize and local maize) as the salt concentration increased in relation to the control and when the three varieties were compared the leaf length and relative growth rate of the local maize was higher in all the three salt concentrations (50, 100 and 150mM) than the other two varieties. The sodium chloride level increased significantly as the salt concentration increased in all the three varieties of maize when compared with their controls.Likewise when the three varieties were compared, the highest increase of sodium chloride was found in maize varieties treated with 150mM of salt and the local maize had the least sodium chloride level of 44.11mM at this concentration. Salt stress significantly (p<0.05) reduced the sucrose levels in the three varieties of maize when compared with their controls at different concentrations of salt, but when the three varieties were compared, the sucrose level of the local maize was lower than the other two varieties at 100mM and 150mM concentrations and the levels of the local yellow maize were 32.06 and 32.03mg/l respectively at these concentrations. The activities of the antioxidant enzymes of these three varieties of maize varied at different salt concentrations, the ascorbate perioxidase and superoxide dismutase activities in local yellow maize at low salt concentration (50mM) were 1.12μ/l and 0.3μ/l respectively and were slightly higher than their activities in the western white agric maize and the western yellow agric maize at the same salt concentration. And at 100mM of salt concentration the catalase and ascorbate perioxidase activities also were higher in the local yellow maize (0.09 and 0.99μ/l respectively) than in the western white agric maize and western yellow agric maize. At 150mM of salt concentration also the catalase activity was 0.928μ/l in the local maize and also higher than the other two varieties (western white agric maize and western yellow agric maize). The growth rate obtained confirmed higher tolerance in local yellow maize and the antioxidant enzyme activities changes suggest that local yellow maize constitutive enzyme system seems to be more efficient than the others.
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