Role of foliar biostimulants (of plant origin) on grapevine adaptation to climate change

Heat waves and drought stress are typical aspects of current climate change, significantly affecting the grapevine physiology in many world growing areas. Biostimulants can play an important role in reducing the negative effects of climate change; that’s why this experiment was set up in order to test two new foliar biostimulants (protein hydrolysates of plant origin). The field experiment was carried out in 2017 and 2018 in Oltrepo pavese area (Lombardia region, northwest Italy, 270 m asl), on a six-year-old vineyard of V. vinifera L. cv. Merlot clone 181 grafted on Gravesac, Guyot trellis, 4,000 vines/ha and not irrigated. Two new protein hydrolysates of plant origin were sprayed twice, just after fruit set and 15 days later, by using 2.5 L/ha. Leaf proteomics and metabolomics were studied in 2017, while productive and qualitative data were recorded in both years at harvest (September 1st, 2017 and August 28th 2018). The most significant findings were: (a) the treatments slowed down the grape ripening, by stimulating vegetative activity and reducing sugar accumulation; (b) less heat and drought stress symptoms were observed in the canopies of treated vines, as compared to the control ones.