Fig. 1

Secondary metabolites content in the root of three licorices species changed with the growth period. Description: Bar charts (mean with standard error) with different lower-case letters represented a significant difference (P < 0.05) was assessed by one-way analysis of variance followed by Bonferroni’s statistic test for multiple comparisons. The same letter indicates no significant difference (P > 0.05). Abbreviations: GIA, GTF and LI mean glycyrrhizic acid, liquiritin and total flavonoid, respectively