Effects of Zinc Foliar application and Sulfur application on quantitative, qualitative and biochemical characteristics in Sunflower (Helianthus anus L.) Under Water Deficit Stress

Water deficit stress is a common a biotic stress that seriously affects crop production in more parts of the world. Thus, in order to study the effects of water deficit stress and zinc foliar application and sulfur application on quantitative and qualitative characteristics of sunflower, an experiment was conducted at Varamin, Iran during 2014 growing season. The experimental design was laid out in a randomized complete block with a split plots arrangement of treatments in three replications. Main plots included three different levels of irrigation (complete irrigation, irrigation withholding at flowering stage and irrigation withholding at seed filling period stage) and sub plots were included four different zinc and sulfur application (untreated zinc and ]sulfur application, zinc foliar application, sulfur application and both zinc foliar application and sulfur application) The results showed that irrigation withholding conditions in different growth stages significantly decreased seed yield, biological yield, harvest index, oil percentage and oil yield and total chlorophyll content, Relative Water Content but by contrast increased superoxide dismutase activity in leaves. Both zinc foliar application and sulfur application treatment had positive effect on all attributes in this experiment. In general, the results of the present study indicate that usage of zinc foliar application reduces the harmful effects of water deficit stress and increases resistance to drought stress in sunflower plant.