Influence of distinctive Osmoprotectnats foliar spray in alleviating the harmful effects of water stress at sensitive growth stages of Maize (Zea mays L.)

Water availability is becoming a significant concern for crop production worldwide. In light of this, a study was conducted in maize crop to explore the effectiveness of various osmoprotectants including sodium nitroprusside nanoparticles (SNP NP) at a concentration of 90 ppm, melatonin (MEL), at 25 ppm and salicylic acid (SA) at 100 ppm in mitigating the adverse effects of drought, by evaluating their impact on morpho-physiological, biochemical and yield attributes of maize (Zea mays L.). Drought stress was induced by withholding irrigation during both the vegetative and reproductive stages of maize and then drought-stressed plants were foliar sprayed with different osmoprotectants. Results revealed that among the osmoprotectants tested, foliar application of salicylic acid at 100 ppm exhibited the most substantial improvement in morpho-physiological parameters (plant height, stem diameter, leaf number, root length, leaf area index, relative water content, leaf chlorophyll and carotenoid content) as well as biochemical parameteters like proline and soluble protein content increased, and enhanced membrane stability under drought conditions. The use of SA proved outstanding as it led to a remarkable 75% higher biological yield than plants subjected to drought stress. On the other hand, the SA foliar spray was successful, resulting in a 78.8% in grain yield. However, the extent of improvement varied depending on the growth stage at which the osmoprotectants were applied. While the foliar application of osmoprotectants showed promising results during the vegetative phase than the reproductive phase of maize. Nonetheless, the osmoprotectants' foliar spray exhibited a yield advantage by preserving photosynthetic pigments and the maize plants' ability to produce seeds under drought stress.