Use of foliar spray of zinc for reducing the adverse effects of boron toxicity in two table grape (Vitis vinifera L.) cultivars

Boron toxicity is a disorders which can limit plant growth in arid and semi-arid areas, and table grape (Vitis vinifera L.) is one of the most important fruit trees grown in these regions. In order to investigate the effect of zinc sulfate on some morphological, physiological and biochemical characteristics of two grapvine cultivars (Ghezel ozum and Hoseini), under toxicity of boron, a greenhouse experiment was conducted with three factors including two grapevine cultivars (Ghezel ozum and Hoseini), four levels of boric acid (0.25 (control), 2.5, 5 and 10 mgL-1) and three levels of zinc sulfate (0 (control), 3 and 6 gL-1) in a completely randomized design with 4 replicates during six months. The results indicated that with increase in boric acid levels in the nutrient solution, leaf number, root length, fresh and dry weight of shoot were reduced. With increase in boric acid level, the leaf cell membrane leakage and the amount of tissue malondialdehyde production were increased. Under boron toxicity, application of zinc sulfate (specially at 6 gL-1) improved growth indices, enhanced antioxidant enzymes activity and reduced the ion leakage in both cultivars. Overall, in the present study, application of zinc sulfate ameliorated some of the adverse effects of boron toxicity in both grape cultivars.