The role of natural exogenous foliar applications in alleviating salinity stress in Lagerstroemia indica L. seedlings

A pot experiment was conducted during 2014 and 2015 seasons in completely randomized factorial design to determine the effect of natural extracts foliar spray of Moringa leaves extract (1:30), humic acid (10%), seaweed (2%), Hogland nutrient solution and tap water as control on growth characteristics (plant height, stem diameter, number of leaves/plant, number of branches/plant, root length, and total dry weight of plant parts (roots, shoots and flowers), floral and chemical characteristics of Lagerstroemia indica grown at various sea salt concentrations (0, 3.12, 6.25 and, 9.37 dS/m) showed that by increasing sea salt concentrations, all growth characteristics, inflorescence number/plant and, inflorescence diameter decreased significantly, while, the number of days to inflorescence increased. Total chlorophylls, carotenoid contents, total carbohydrates and N, P, K%. Meanwhile, proline content, total soluble phenols, Na, Ca, and antioxidant enzymes (catalase, superoxide dismutase and peroxidase) increased at the high level of salinity (9.37 dS/m). The usage of the Moringa leaf extract was significantly improved growth, inflorescence, as well as chemical characteristics, but also, decreased significantly Na under the adverse conditions of the studied sea salt stress. Moringa leaf extract could promote and protect crape myrtle plants against injuries by sea salt stress can substitute inorganic or chemical fertilizer being safe and cheap.