Biostimulative effect of amino acids on the enzymatic and metabolic response of two Capsicum annuum L. cultivars grown under salt stress

'Berenyi F1 ' and 'Caro F1 ' pungent pepper cultivars were grown under 20 mM and 40 mM NaCl salt stress conditions. A biostimulant of hydrolyzed animal protein was applied to the leaves to study the effects of its application on the activity of capsaicin synthase (CS), phenylalanine ammonia lyase (PAL), and peroxidase (POX). In addition, the effect of salinity and biostimulant on total and individual capsaicinoid content was investigated. When the biostimulant was applied, enzyme activity improved between 27.2% (CS) and 576.7% (PAL) in both cultivars, depending on salt stress and cultivar. Peroxidase activity was greatly reduced in plants treated with biostimulants compared to plants not treated with biostimulants. Capsaicinoid content correlated strongly with biostimulant application and salinity. With the application of biostimulants, we can increase the activity of these important enzymes in pepper plants to a whole new level and improve the biosynthesis of capsaicinoids under stress conditions, which are the main characteristic metabolite in peppers.