Zinc pulverization alleviates the adverse effect of water deficit on plant growth, yield and nutrient acquisition in grapevines (Vitis vinifera L.)

Grapevine (Vitis vinifera L.) is an important dryland pulse crop in many parts of the world. However, productivity and quality are often limited by periods of water deficit. In a number of drought regions, drought is accompanied with zinc (Zn) deficiency, one of the most serious problems causing significant decreases in yield and quality in viticulture. In spite of this fact, possible effect of Zn treatment to alleviate the adverse effect of water stress on grapevines has not been studied. A pot culture research was designed under controlled glasshouse condition with the objective to investigate the effects of Zn pulverization on growth, physiology and nutrient acquisition of grapevine cultivars 'Italia' and 'Alphonse Lavallée' subjected to different irrigation levels. Six years old grapevines of the cultivars grafted on a drought tolerant rootstock Richter 99 (Berlandieri x Rupestris) were cultivated in pots (70 L) and subjected to two different irrigation regimes, FI-100% (replenishing the substrate water storage up to field capacity) and DI (40% of FI). Half of the vines for each irrigation group received leaf Zn pulverization (1%) twice (prior to flowering and berry set). DI caused overall decreases in shoot and leaf developments of cultivars, while Zn pulverization had alleviating effects on such vegetative growth in general. Generally, leaf chlorophyll content of the vines was also improved by Zn under both FI and DI conditions. Spraying of the leaves and green bunches with chelated Zn supported the grapevines of both cultivars 'Italia' and 'Alphonse Lavallée' in varying degrees by improving acquisition of many plant nutrients, promoting the vegetative and generative developments. Considering the overall response of the vines to Zn pulverization with a particular concern to DI condition, improved shoot and leaf growth, greener leaves, enhanced berry development and vine yield allow us to recommend Zn spraying as an environmentally friendly and sustainable cultural practice under drought stress which has been increasing with global climate change.