Effects of NaCl Salinity and Nitrogen levels on Growth, and Vitamin C and Nitrate concentrations of Halophyte Vegetable Suaeda aegyptiaca

Increasing salinity in agricultural lands has led to the limitation of crop cultivation and reduction of crop yields. Therefore، many researchers in the world focus on finding alternative crops. Halophytes، because of some mechanisms such as antioxidant systems are resistant to salt stress. In order to study the effects of NaCl salinity and nitrogen levels on growth، ascorbic acid and nitrate contents in the edible halophyte S. aegyptiaca، a factorial experiment with 5 levels of NaCl including 10، 20، 40، 60 and 80 dS m-1 as the first factor and three levels of nitrogen including 25، 50 and 75 mg kg-1 in urea form as the second factor in completely randomized design with three replications was conducted under the greenhouse conditions. NaCl treatments were applied after the plants had reached a stand. Nitrogen was also added at two stages within 10 days. The results showed that the highest fresh and dry weights of plants were obtained at 20 dS m-1 salinity level. The fresh and dry weights decreased more by increasing salinity. At salinity levels of 10 and 20 dS m-1، the fresh and dry weights increased with increasing nitrogen levels، but at higher salinity levels، the moderate levels of nitrogen produced the highest fresh and dry weights. With increasing salinity up to 40 dS m-1 the vitamin C content firstly increased and then decreased with further increase in salinity. The vitamin C levels also decreased with increasing nitrogen levels. Furthermore، the nitrate concentration increased with increasing nitrogen levels. At salinity levels of 10، 20 and 40 dS m-1 concentration of nitrate at different levels of nitrogen was constant but decreased at 60 and 80 dS m-1 salinity levels with decreasing nitrogen levels.