Seed origin effects on growth, physiological and biochemical traits of Moringa oleifera seedlings grown under drought and salinity conditions

The versatile plant Moringa oleifera has spread beyond its native range and is now widely cultivated across diverse geographic regions. Global climate change requires careful seed selection before planting to ensure adaptation to the target environment. In the present study, M. oleifera seeds were collected from two geographical origins (Bouhedma Park, Tunisia, and Jeddah, Saudi Arabia) and cultivated in the National Institute of Research in Rural Engineering, Waters and Forests area (INRGREF, Tunisia), under salinity, drought, and combined drought–salinity treatments. Growth parameters, photosynthetic pigments, proteins, total carbohydrate, phenolic compounds, Malondialdehyde and hydrogen peroxide (H₂O₂) contents, antioxidant enzyme activities such as superoxide dismutase, catalase, ascorbate peroxidase, and glutathione reductase were determined. The data showed that six-month-old Saudi plants reached a height of 60 cm and a stem diameter of 10 mm. Tunisian plants of the same age reached a height of 55.8 cm and a stem diameter of 11.34 mm. Protein and total carbohydrate contents were higher in seeds from Saudi Moringa plants. Saudi Moringa plants also had higher leaf protein contents than Tunisian plants. Antioxidant enzyme activities and total phenolic compound contents increased in both Saudi and Tunisian plants under drought and high salinity. Consequently, current results showed that although some morphological and biochemical differences were observed between plants derived from Saudi and Tunisian seeds, Moringa trees showed substantial tolerance to drought and salinity. The tolerance of Moringa to severe environmental conditions may contribute to its potential for sustainable cultivation in stress-prone environments.