Fig. 2

Metabolomics profiles of walnut endopleura. A Correlation analysis of HGWR, SJWR, SHWR and mix samples. The color indicates the level of correlation of each sample, from low (blue) to high (red). B PCA analysis of different samples. C Component analysis of the identified metabolites from walnut endopleura. D Classification of differential metabolites common among the three groups of samples. The middle of the circle is a Venn diagram of the differential metabolites of the three groups of samples. E Pathway enrichment analysis of common DAMS for three samples