The Impact of Salinity and Nitrogen on the Growth and Mineral Elements of woSunflower Cultivars (Alstar and Euroflore)

Two hydroponic trials were conducted under controlled conditions to study the effect of sodium chloride salinity and nitrogen supply on two sunflower (Helianthus annuus L.) cultivars. A factorial experiment in completely randomized design (CRD) with 3 replications was carried out. The first factor included sunflower cultivars (i.e.,Alstar&Euroflore). The second and third factors (i.e., salinity & nitrogen levels) were established as 0, 50, 100, and 150 mM of NaCl and 0, 2, and 4 mM of NH4NO3, respectively. The sunflower cultivars were grown in aerated full-strength Hoagland solution. Salt and nitrogen treatments were added to the Hoagland solution jars at 2-leaves stage. After four weeks, the plants were harvested. The growth parameters including fresh and dry weights of shoots and roots, leaf number, leaf area, and the mineral elements including N, P, K and Na contents were determined. The results of variance analysis indicated that the growth parameters of the two sunflower cultivars decreased significantly with increasing the salinity levels, as compared to the untreated controls. It was observed that the low nitrogen level could ameliorate the effectsof different levels of salinity. In both sunflower cultivars, nitrogen and Sodium contents were increased in the roots with an increase in the salinity and nitrogen levels. Shoot potassium and phosphorus contents were decreased in Alstar and increased in Euroflor cultivars.