Interactive Effects of Iron Nanoparticles and Salinity on Growth and Physiology Of Onion (Allium cepa L.)

Abstract

Background: Salinity is one of the most significant abiotic stresses affecting crop production, which affects plant growth, photosynthesis, oxidative balance and nutrient uptake. The application of nanotechnology, especially the iron nanoparticles (Fe-NPs) is a promising strategy for enhancing plant tolerance to saline environments.

 Objectives: The objective of this study was to investigate the role of spinach-medicated iron nanoparticles mediated through spinach on alleviating salinity-induced damage in onion (Allium cepa L.) in terms of growth, physiological, biochemical and mineral responses.

Methodology: The pot experiment was carried out in 3 x 4 factorial completely randomized design (3 replicates) with salinity: 0, 150 and 200 mM NaCl and Fe-NP foliar application: 0, 250, 350 and 450 ppm. The growth parameters, photosynthetic pigments, oxidative stress parameters, antioxidant metabolites and mineral nutrients were measured by standard procedures.

Results: The salinity reduced growth, photosynthetic contents, and nutrient accumulation, and increased the malondialdehyde (MDA) accumulation that suggests increased oxidative damage. The Fe-NPs were applied to the leaves, which led to better growth parameters, as well as increased chlorophyll (a & b) and carotenoids, and decreased lipid peroxidation, while increasing antioxidant compounds such as flavonoids, ascorbic acid, and phenolics. Fe-NPs also positively affected mineral nutrient balance by enhancing the Fe accumulation and minimizing ionic disturbances due to salinity. These nanoparticles had the greatest ameliorative action at 450 ppm nanoparticles.

Conclusion: The spinach mediated iron nanoparticles significantly reduced the physiological and biochemical constraints of onion under salinity stress by enhancing photosynthetic pigments, antioxidant defense and nutrient homeostasis. The results indicated that iron nanoparticles is a promising approach to enhance the performance of onion under salinity stress.