Abstract
Maize is a sensitive crop to drought and heat stresses, particularly at the reproductive stages of development. The present study investigated the individual and interactive effects of drought (50% field capacity) and heat (38 °C/30 °C) stresses on morpho-physiological growth, yield, nutrient uptake and oxidative metabolism in two maize hybrids i.e., ‘Xida 889’ and ‘Xida 319’. The stress treatments were applied at tasseling stage for 15 days. Drought, heat and drought + heat stress caused oxidative stress by the over-production of ROS (O2−, H2O2, OH−) and enhanced malondialdehyde contents, which led to reduced photosynthetic components, nutrients uptake and yield attributes. The concurrent occurrence of drought and heat was more severe for maize growth than the single stress. However, both stresses induced the metabolites accumulation and enzymatic and non-enzymatic antioxidants to prevent the oxidative damage. The performance of Xida 899 was more prominent than the Xida 319. The greater tolerance of Xida 889 to heat and drought stresses was attributed to strong antioxidant defense system, higher osmolyte accumulation, and maintenance of photosynthetic pigments and nutrient balance compared with Xida 319.
Highlights
Under natural environments, crops are often subjected to different abiotic stresses simultaneously during their life cycle which adversely affect the growth and productivity of field crops[1,2]
Zandalinas et al.[2] and Lamaoui et al.[22] concluded that drought and heat stresses generally trigger similar physiological responses in plants, plants were severely damaged by the combined action of both stresses than by the individual stress factor, indicating that conserved defense mechanisms exist among different plant species to deal with a combination of heat and drought stresses
Ears/plant and kernel rows/ear in both maize hybrids remained unaffected by all stress treatments (Table 2)
Summary
Crops are often subjected to different abiotic stresses simultaneously during their life cycle which adversely affect the growth and productivity of field crops[1,2]. Extreme temperature and water deficit conditions are two of the most frequent environmental threats to crop growth and productivity, and the food security under changing climate[3,4,5,6,7,8]. These stresses negatively affect the yield of major staple food crops[5,6,9], that account for 60% of global food energy supply[10]. The specific objectives of the study were (1) to investigate the individual and concurrent effects of heat and drought stresses on morpho-physiological growth, grain yield, osmolyte accumulation, nutrient uptake and oxidative status in maize, (2) to examine the basis of maize tolerance against drought and heat stresses, and (3) to assess the performance of two different maize hybrids under drought and/or heat stresses
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