Untargeted metabolites and chemometric approach to elucidate the response of growth and yield attributes on different concentrations of an amino acid based biostimulant in two lettuce cultivars

Abstract

The study aims to underpin biochemical mechanisms induced by the application of different concentrations of an amino-acid based Phytostim® biostimulant on growth and yield attributes. Different concentrations of Phytos- tim® biostimulant: 0 (untreated), 1, 3, and 6% were foliar applied on lettuce cultivars (‘Lara’ and ‘Elisa’). After 45 days of transplanting, analysis growth and yield attributes, biochemical analysis and LC-MS untargeted metabolites profile were performed. Application of 3% dose improved both growth and yield parameters in both cultivars in comparison to the 6% dose which inhibited growth. Similar trend was observed for biochemical and antioxidant analysis (phenolic, flavonoids, carotenoids, chloroplyll a and b and scavenging activity). The PCA and OPLS-DA score-plot clustered the metabolome profile of biostimulant treated vs untreated samples with major heterogeneity distinction observed in the untreated samples. Obtained results validate the use of bio- stimulants in agriculture while giving information on the effects of the treatments towards changes in the chemical composition within the studied cultivars.