Fig. 5

Quality control of metabolites identified in extracts of mulberry seedling samples. a Pearson correlation coefficients and b principal component analysis of metabolites extracted from control and treated mulberry plants after treatment with 0 mmol/L, 50 mmol/L and 100 mmol/L NaCl; each sample was analyzed in triplicate, and a quality control mixture was used for metabolomics. c K-means clustering analysis showing the dynamic accumulation of differentially abundant metabolites under different salt concentrations. The horizontal coordinate indicates the sample grouping, the vertical coordinate indicates the standardized metabolite relative content, ‘Subclass’ indicates the metabolite category number with the same change trend, and ‘total’ indicates the number of metabolites in that class. The data were plotted using the prcomp function with default settings in R software [39]