Enhancing the Valorization of Secondary Treated Wastewater Irrigation for Seed Germination and Early Seedling Growth of Tomato (Solanum lycopersicum L.) Using Moringa oleifera Leaf Extract under Greenhouse Conditions

Abstract

This study investigated the potential of Moringa oleifera leaf extract (MLE) to enhance the agronomic performance of secondary treated wastewater (TWW) used for seed germination and early seedling growth of tomato (Solanum lycopersicum L. cv. Marmande) cultivation. A Petri-dish germination assay and a pot experiment conducted under greenhouse conditions were carried out. Tomato seeds were irrigated with TWW alone or with TWW supplemented with MLE at 2, 4, and 6 mL L⁻¹. Germination behaviour, early seedling growth, morphological traits, and physiological parameters, including chlorophyll content and relative water content, were evaluated. MLE application significantly improved germination rate (GR) and uniformity, with the most pronounced effects observed at moderate concentrations (2–4 mL L⁻¹). These improvements were associated with enhanced seedling vigour, increased chlorophyll accumulation, and better plant water status. In contrast, the highest concentration (6 mL L⁻¹) slightly reduced these benefits, indicating a dose-dependent biostimulant response. Overall, combining MLE with treated wastewater represents an eco-efficient strategy to improve crop establishment while mitigating the constraints associated with reclaimed water use in arid and semi-arid agriculture.