Antioxidative system in maize roots as affected by osmotic stress and different nitrogen sources
2010
M. Vuletić | V. Hadži-Tašković Šukalović | K. Marković | J. Dragišić Maksimović
The activities of antioxidative enzymes and contents of proline and total phenolics were assayed in roots of two maize (Zea mays L.) genotypes grown in a medium containing nitrate (NO3 -) or both nitrogen forms, nitrate and ammonium (NH4 +/NO3 -). An increase in the activities of class III peroxidases (POD), superoxide dismutase (SOD), ascorbate peroxidase (APX), ascorbate oxidase (AO) and proline content, and decrease in phenolic content were observed in NH4 +/NO3 - in comparison with NO3 - grown plants. When polyethylene glycol (PEG) was added to both nitrogen treatments, the content of total phenolics and proline was increased, especially in NH4 +/NO3 - treatment. The PEG treatment decreased enzyme activities in NH4 +/NO3 - grown plants, but in NO3 - grown plants activities of POD and SOD were increased, opposite to decreased APX and AO. Isoelectric focusing demonstrated increased activities of acidic POD isoforms in PEG treated NO3 - grown plants, and lower activities of both, acidic and basic isoforms in NH4 +/NO3 -grown plants.
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