Morphological and biochemical changes in maize under drought and salinity stresses in a semi-arid environment |
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Authors: | Leila Romdhane Leila Radhouane Muhammad Farooq Cristian Dal Cortivo Anna Panozzo |
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Affiliation: | 1. National Institute of Agronomic Research of Tunisia (INRAT), University of Carthage, Ariana, Tunisia;2. Department of Crop Sciences, College of Agricultural and Marine Sciences, Sultan Qaboos University, Muscat, Oman;3. Department of Agronomy, Food, Natural Resources, Animals and the Environment, University of Padua, Legnaro (Padua), Italy |
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Abstract: | AbstractThis study investigated some morphological and biochemical responses of maize to drought and salinity in open field in Tunisia with the aim of gaining insights into tolerance mechanisms. After seedling emergence, five treatments were applied until maturity: optimal water supply (control, 100% of maximum evapotranspiration - ETM); irrigation at 70% ETM (moderate drought) and at 35% ETM (severe drought); optimal supply of water containing 3?g NaCl L?1 (moderate salinity) and 6?g NaCl L?1 (severe salinity). Here, we demonstrated that extreme drought and salinity severely decreased the leaf area (?74% and ?55%, respectively) and the above-ground biomass (?35% and ?31%, respectively) at silking stage, indicating that the photosynthetic leaf apparatus is highly sensitive and that drought has a greater effect than salinity. Grain yield losses were also exacerbated under extreme stress conditions, viz. severe drought (?85% versus controls) and severe salinity (?73%), while productivity under moderate salinity approximated that of moderate drought, possibly due to increases in leaf chlorophyll and carotenoid content and K/Na ratio. The leaf area and its relative water content were positively correlated with grain yield under both salinity and drought stresses, and may therefore be used as markers for effective screening of maize genotypes for better stress tolerance. |
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Keywords: | Carotenoids chlorophyll drought and salinity stress maize hybrid leaf area proline |
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