Effect of Foliar Spray of Zinc Oxide on Some Antiox idant Enzymes Activity of Sunflower under Salt Stress

Abstract

This study investigated the effects of foliar appli cation of normal and nanoparticles of zinc oxide (ZnO) on the growth, proline content, an d some antioxidant enzyme activities of sunflower cultivars at different salinity levels . Treatments included five cultivars ( Helianthus annuus L. cvs. Alstar, Olsion, Yourflor, Hysun36, and Hysu n33), two salinity levels (0 and 100 mM NaCl), and three foliar applic ations (none-sprayed, ZnO normal and nanoparticles at a rate of 2 g/L). Olsion showe d the highest proline content and superoxide dismutase activity (SOD) among the studied cultivars under saline condition. Foliar spray of ZnO improved SOD activity and shoot dry weight of sunflower. Nanoparticles of ZnO had positive effect on biomass production of sunflower plants compared to the normal form. According to the resul t, Olsion and Hysun33 cultivars were suitable for saline conditions, whereas Hysun36 was appropriate for normal condition. Keywords : Nanoparticles, Superoxide dismutase, Helianthus annuus , Proline