One -year -old date palm seedlings (Phoenix dactylifera L.) were studied to assess the impact of salinity on root system architecture and biochemical parameters. Saline water was used for irrigation, and a year -long analysis was conducted. Continuous monitoring in rhizotrons revealed increased root growth, lateral root production, and enhanced protein, chlorophyll, and carotenoid production at 100 mM NaCl. However, soluble sugar content decreased. At 200 mM NaCl, root length, lateral roots, and various biochemical parameters decreased significantly, except for proline, which accumulated, suggesting osmoregulation. These findings highlight that moderate salinity stimulates growth and biochemical functions, while higher salinity levels adversely affect these parameters, with proline serving as a crucial osmoregulatory component in date palm seedlings under salt stress.