Effect of Foliar Application of Zinc Sulfate on Winter Hardiness of Grapevine cv.  Bidaneh Sefid'

The purpose of this study was to investigate the effects of zinc on cold hardiness of grapevine, cv. ‘Bidaneh Sefid’. Zinc sulfate at three concentrations of zero (control), 0.04 and 0.08 % were foliar sprayed on grapevines for five times during growing season. On Dec 25th and Feb 23rd, cane samples were prepared and analyzed for their content of carbohydrate, proline, protein and relative water. Samples also were treated at 0, -3, -6, 9, -12, -15, -18, -21, -24, -27 and -30 °C for three hours in a freezing chamber to be analyzed according to tetrazolium test and electrolyte leakage. Results showed that by increasing zinc sulfate, grapevine's relative water content reduced while amount of carbohydrate, proline, and protein increased. Treated grapevines by zinc sulfate (0.08%) revealed the lowest electrolyte leakage and the highest tissue survival. Positive significant correlations were found between results of LT50 calculated based on tetrazolium test and electrolyte leakage and carbohydrate, proline, and protein content of cane. It can be concluded that application of zinc sulfate could potentially increase cold hardiness of grapevine cv. ‘Bidaneh Sefid’.