Efficacy of FeSO4 nano formulations on osmolytes and antioxidative enzymes of sunflower under salt stress

This study investigated iron (II) sulfate (FeSO4) effects in two forms on some antioxidant enzyme activity, osmoregulators and sunflower growth under salt stress. Treatments included five cultivars (Alstar, Olsion, Yourflor, Hysun36 and Hysun33), two salinity levels (control and 100 mM NaCl), and three foliar applications (none-sprayed, FeSO4 normal and nano-particles at a rate of 2 g L−1). As a results, salt stress increased superoxide dismutase (SOD), catalase (CAT), ascorbate peroxidase (APX), polyphenol oxidase (PPO), peroxidase (POX), pyrroline-5-carboxylate synthase (P5CS) and invertase activities; and also proline, soluble carbohydrates, malondialdehyde (MDA) content and reactive oxygen species (ROS) generation; however, reduced shoot dry weight and seed yield. Foliar spray of FeSO4 in two forms enhanced CAT, PPO, POX, invertase activity, soluble carbohydrates and decreased MDA content and ROS generation compared to non-sprayed plants under saline condition. In general, FeSO4 in nano was more effective than normal form in improving the growth of sunflower. As an average, the spray of FeSO4 increased proline content of Alestar cultivar under 100 mM salinity, which related with P5CS activity but reduced leaf proline content of Olsion and Hysun33 under non-saline condition. In addition, shoot dry weight and seed yield of sunflower were increased by FeSO4. Leaf Fe concentration of cultivars was strongly intensified by FeSO4 foliar spray under two conditions compared to non-sprayed treatment. Overall, the usage of FeSO4 alleviated the negative impact of salt stress, although the positive effects of nano-particles were more than the normal form. © 2018, Indian Society for Plant Physiology.