Effects of Foliar Application of Common and Nano-sized of Iron Sulphate on the Growth of Sunflower Cultivars under Salinity

To study the effects of foliar application of common and nano-sized iron sulphate on five sunflower cultivars (Alster, Olsion, Hysun36, Yourflour and Hysun33) under two levels of salinity (0 and 100 mM NaCl), a pot experiment in factorial based using a randomized complete block design with three replications was conducted. Plant height, leaf area, shoot weight, chlorophyll content and the concentration of K and Fe in shoots were decreased and the concentration of Na was increased under salinity. Foliar application of iron sulphate in either forms increased plant height, leaf area, shoot dry weight, quantum yield, chlorophyll content, Fe concentration and also decreased Na concentration. Foliar application of nano-sized of iron sulphate increased plant height, leaf area, shoot dry weight, chlorophyll a and total content up to 4, 9, 7, 30 and 13% in comparison with foliar application of common form. The effects of salinity and cultivar interaction was significant on leaf area, shoot weight and K/Na ratio. The percentage reduction of these parameters in Olsion cultivar was lower than other cultivars at saline stress. In Yourflour cultivar the absorbance of iron was significantly higher in the nano form than in common form. The results of this experiment showed that the nano form of iron sulphate compared to the common form had greater positive effect on the biomass production of sunflower. However, under the conditions of this experiment, the application of nano-sized of iron sulphate showed no significant advantage over common form in terms of the alleviation of salinity effects.