Enhancement of yield, physiological characteristics, and oxidative stability of date palm (Phoenix dactylifera L.) trees under salt stress using biogenic selenium nanoparticles

Salinity poses a substantial risk to agricultural productivity. This work explored the use of biogenic selenium nanoparticles (BSeNPs) synthesized by Streptomyces ferrugineus, characterized by their spherical morphology (41 nm diameter), and -25.3 mV surface charge, to mitigate salinity stress in date palm trees. Over two growing seasons (2022 and 2023), BSeNPs (0, 5, 10, 20, 40, and 80 mg/L) were applied as foliar sprays and soil drenches to assess their impact on growth, yield, and oxidative stability. Salinity stress reduced growth, chlorophyll content, relative water content (RWC), and ascorbic acid, while increasing catalase, ascorbate peroxidase, malondialdehyde, and hydrogen peroxide levels. The soil application of BSeNPs at 40 mg/L significantly increased chlorophyll content by 28.8–29.5%, RWC by 33.3%, and ascorbic acid by 90.5%. It also reduced proline by 48.8–51.7%, malondialdehyde (MDA) by 31.0–33.3%, and the activities of ascorbate peroxidase (APX) and catalase (CAT) by 32.1–40.0%, and 16.7–25.0%, respectively, compared to untreated controls. Biogenic SeNPs enhanced the antioxidant defense system, reduced reactive oxygen species-induced oxidative damage, and minimized lipid peroxidation. This study is the first to demonstrate the potential of BSeNPs derived from actinobacteria to mitigate salinity-induced oxidative stress in date palm trees while simultaneously enhancing fruit yield and quality. By offering a sustainable and eco-friendly solution, BSeNPs pave the way for protecting high-value crops like date palms against the adverse effects of salinity. This innovative approach not only safeguards agricultural productivity under challenging environmental conditions but also promotes sustainable farming practices, highlighting the transformative role of BSeNPs in modern agriculture.