Effect of Foliar Application of Nano-selenium on the Anatomical Characteristics of Date Palm Phoenix dactylifera L. Barhi Cultivar under Salt Stress

This study investigated the effect of salinity on the anatomical features of date palm (Phoenix dactylifera L.) and the potential roles of nano selenium (Se NPs) in alleviating the adverse effects of salinity. Two concentrations (80 and 160 mg.L-1) of SeNPs were applied as a foliar spray on date palms irrigated with different concentrations of saline water (2.5 [control], 5, 10 and 20 ds.m-1). Results showed that 5 ds.m-1 salinity had no significant effect on the anatomical structure of date palm, whether applied alone or in combination with foliar spray of Se NPs. However, the vascular bundle dimensions and thickness of the xylem, phloem and mesophyll were significantly higher in plants exposed to 10 ds.m-1 salinity compared with the control plants. In particular, foliar spray of SeNPs at 80 mg.L-1 concentration enhanced the effect on these plants. By contrast, 20 ds.m-1 salinity significantly reduced all studied parameters except for the thickness of the upper and lower cuticle, which increased. Se NPs at 80 mg.L-1 concentration had a significant effect in alleviating the adverse effects of salinity at high levels. The results of this study proved that SeNPs at 80 mg.L-1 concentration were more effective in alleviating the adverse effects of salinity on the anatomical structure of date palm leaves than 160 mg.L-1 concentration.