MITIGATION THE HARMFUL EFFECT OF IRRIGATION WATER SALINITY ON ROSA HYBIRIDA, CV. CENTRIX BY USING ARGININE AND MAGNETIC IRON

Water scarcity has become a critical challenge in various countries of the world that are suffering from a lack of water resources which led to increasing the need for irrigation water. So, the main purpose of this investigation was to study increasing resistance of Rosa hybirida cv. Centrix to irrigation with diluted sea water by using arginine and magnetic iron. The experiment was conducted on Rosa cv. Centrix during the two successive seasons of 2016 and 2017 to evaluate the effects of foliar spraying with arginine at (100 and 200 mg L^-1) and soil application with magnetic iron at (4 and 6 g pot^-1) were studied combined with irrigation by diluted sea water at three concentrations (5, 10 and 15%) on vegetative growth, floral and chemical parameters. The results showed that plant height, number of branches, number of leaves, leaf area, fresh and dry weights of leaves as well as floral characters such flowering stem length, number of flowers, flower diameter, flower fresh and dry weights were increased at lower levels of salinity of diluted sea water irrigation (5%), and then gradually decreased with increasing irrigation water salinity from 5 to 15% as compared to non-saline water (control). Moreover, relative water content, photosynthetic pigments, reducing sugars, mineral uptake (N, P, K, Mg and Ca %) were negatively affected by salt stress while increasing electrolyte leakage (%), proline and total sugars as well as higher contents of Na⁺. In contrast to this, arginine or magnetic iron ameliorated all parameters in plants which were irrigated with all diluted sea water concentrations. It could be noticed that the application of arginine at 200 mg L^-1 or magnetic iron at 6 g pot^-1 could partially alleviate the harmful effect of salinity stress on plant growth and biochemical constituents of Rosa cv. Centrix plant. From the obtained results, it could be recommended that spraying Rosa plants irrigated by diluted sea water with arginine at 200 mg L^-1 could overcome the deleterious effects of salinity.