Modulations in Physiological and Biochemical attributes of Citrus Limon by selenium nanoparticles (SeNPs) under salinity stress

Abstract

Salinity is recognized as a significant abiotic stressor that impairs crop growth and productivity. Elevated - soil and irrigation water salinity poses substantial ecological challenges for agriculture, particularly in semiarid and arid regions. High sodium (Na⁺) concentrations induce osmotic stress, leading to water deficits within plant cells. However, using nanoparticles can mitigate salt stress and enhance plant growth. This study investigates the effects of selenium nanoparticles on the physiobiochemical characteristics of Citrus limon L. seedlings under salt stress. Selenium nanoparticles act as both reducing and capping agents. Six-month-old lemon seedlings were subjected to varying salinity levels (100 mM and 200 mM NaCl) and treated with foliar applications of selenium nanoparticles at - 25 mg/L and 50 mg/L concentration. Most of the nanostructures were observed in the size range of 20–40 nm and anisotropic and irregular in shape. The results indicated that 200 mM NaCl significantly reduced the morphological and physio-biochemical parameters of the seedlings. However, a 50 mg/L concentration of SeNPs notably improved fresh and dry weights of roots and shoots and increased chlorophyll content. Biochemical attributes such as SOD, POD, CAT, APX, TSS, TFA, Proline, H₂O₂, and MDA were elevated under 200 mM NaCl, while NPK levels decreased. A concentration of 50 mg/L SeNPs was identified as optimal for enhancing the morphological and physiobiochemical parameters of C. limon seedlings under salt stress.