Interactive Effects of Melatonin and Nitrogen Improve Drought Tolerance of Maize Seedlings by Regulating Growth and Physiochemical Attributes

Abstract

Melatonin plays an important role in numerous vital life processes of animals and has recently captured the interests of plant biologists because of its potent role in plants. As well as its possible contribution to photoperiodic processes, melatonin is believed to act as a growth regulator and/or as a direct free radical scavenger/indirect antioxidant. However, identifying a precise concentration of melatonin with an optimum nitrogen level for a particular application method to improve plant growth requires identification and clarification. This work establishes inimitable findings by optimizing the application of melatonin with an optimum level of nitrogen, alleviating the detrimental effects of drought stress in maize seedlings. Maize seedlings were subjected to drought stress of 40–45% field capacity (FC) at the five-leaf stage, followed by a soil drenching of melatonin 100 µM and three nitrogen levels (200, 250, and 300 kg ha−1) to consider the changes in maize seedling growth. Our results showed that drought stress significantly inhibited the physiological and biochemical parameters of maize seedlings. However, the application of melatonin with nitrogen remarkably improved the plant growth attributes, chlorophyll pigments, fluorescence, and gas exchange parameters. Moreover, melatonin and nitrogen application profoundly reduced the reactive oxygen species (ROS) accumulation by increasing maize antioxidant and nitrogen metabolism enzyme activities under drought-stress conditions. It was concluded that the mitigating potential of 100 µM melatonin with an optimum level of nitrogen (250 kg N ha−1) improves the plant growth, photosynthetic efficiency, and enzymatic activity of maize seedling under drought-stress conditions.

Application of 2,4-Epibrassinolide Improves Drought Tolerance in Tobacco through Physiological and Biochemical Mechanisms

“…The 0.05 mM EBR was sprayed on plants every three days. For WW plants, the moisture content was retained at a field capacity (FC) of 80%, whereas 60% FC for DS was based on daily measurement of pot weight [ 37 ]. Drought stress was applied to plants for 24 days.…”

Improving the effects of drought priming against post-anthesis drought stress in wheat (Triticum aestivum L.) using nitrogen

“…Grassi and Magnani, (2005) found that adequate N content partially restored the photosynthetic biochemistry compared to limited N availability. Previous studies have reported that when the drought stress level intensifies, it reduces the leaf area, which subsequently affects photosynthetic pigmentation and reduces stomatal conductance and transpiration rate ( Ahmad et al, 2022 ). In this manner, supporting the plant’s water status and stomatal opening under high N is important to maintaining the conductance of leaf to CO 2 , photosynthetic responses, and electron transfer ( Liu et al, 2013 ).…”

Functional Characterization of Arylalkylamine N-Acetyltransferase, a Pivotal Gene in Antioxidant Melatonin Biosynthesis from Chlamydomonas reinhardtii

“…Melatonin has diverse functions in plant growth, development, and biotic and abiotic stress responses [ 9 , 10 , 46 , 47 , 48 , 49 ] by modulating the cellular redox balance [ 50 , 51 , 52 ] and protein quality control [ 53 ]. Additionally, melatonin functions in concert with other plant hormones during growth and under stressful conditions [ 54 , 55 ].…”