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IMPROVEMENT IN SALT TOLERANCE OF MAIZE BY EXOGENOUS APPLICATION OF GLYCINEBETAINE : GROWTH AND WATER RELATIONS

KHALID NAWAZ AND ^*MUHAMMAD ASHRAF

Abstract: Effect of exogenous glycinebetaine (0, 50, and 100 mM) applied at different growth stages i.e., vegetative, reproductive and both at the vegetative and reproductive stages on growth and water relations was assessed in the plants of two maize cultivars, Golden and C-20 under salt stress. Salt stress impaired growth by reducing plant fresh and dry biomass of both maize cultivars. Imposition of salt stress also had adverse effects on leaf water potential, leaf osmotic potential and leaf turgor potential. However, salt induced reduction in growth of both maize cultivars was ameliorated by exogenously applied GB. Furthermore, GB applied at the vegetative growth stage was more effective in ameliorating the adverse effects of salt stress on both maize cultivars than when applied at the reproductive stage or at both the vegetative and reproductive growth stages. Leaf water potential and leaf turgor potential of the salt stressed plants of both cultivars were increased due to foliar application of GB. The ameliorative effect of GB on growth of both maize cultivars under saline conditions was due to GB-induced improvement in plant water status. The adverse effects of salt stress on maize can be alleviated by the exogenous application of GB at different growth stages by modulating water relations.

Department of Botany, University of Agriculture, Faisalabad, Pakistan.