Protein hydrolysate-based biostimulants: origin, biological activity and application methods

Protein hydrolysates (PHs) is an important group of plant biostimulants defined\r\nas mixtures of polypeptides, oligopeptides and amino acids which are manufactured\r\nfrom protein sources using partial hydrolysis. PHs are generally applied as foliar\r\nsprays or near the roots. PHs are widely used in agricultural crops largely for\r\nimproving plant nutrient uptake, growth, yield and fruit quality and also for their\r\nameliorating effect on crop tolerance to abiotic stresses. In the current paper, we give\r\nan update of the chemical characteristics, the timing and frequency of PHs\r\napplication, the effects of PHs on plant metabolism and physiology, the biostimulant\r\nactivities on yield and product quality. We report several experimental data on the\r\napplication of a commercial plant derived-protein hydrolysate ‘Trainer’ on\r\nagricultural crops grown under different environmental conditions.