Mechanism of tolerance and adaptive strategies developed by Moringa oleifera (L) during its growth under a salt constraint in hydroponics

Moringa oleifera (L) is a promising species to be used in reforestations of dry areas. A question that remains to be investigated is its resistance to salinity conditions. This work’s major goal was to investigate the response of this species in increasing salinity conditions, in order to increase our understanding on the mechanisms of tolerance and/or sensitivity and of the morpho-physiological and biochemical responses of Moringa plants under a salt constraint. Moringa seedlings were subjected to increasing concentrations of NaCl, 0 (control), 50, 100 and 150 mM NaCl. The results suggest that the variations in the responses of the parameters analyzed depend on the concentration and the duration of application of the salt. Vertical growth, relative average growth rate (RGRh), and relative water content showed a great variability of responses, depending on the concentration and the duration of application of NaCl. Leaf area (SF) was affected by salinity whereas leaf succulence index (ISF) and photosynthetic pigments (chlorophylls (a), (b), were significantly improved by such stress. The results suggest a strong resistance of the species to high doses of NaCl and in particular those greater than 50 Mm. Salinity conditions cause the accumulation of organic solutes (proline and soluble sugars), as a physiological adaptation to prolonged salinity.