FER regulates the flowering time in Arabidopsis. a Photographs of plants of various genotypes grown for 35 days under LD conditions. b The flowering times were measured as days to flower under LD conditions. Asterisks indicate a significant difference compared with WT (n = 15, **P < 0.01, one-way ANOVA with Tukey’s test). c Statistical analysis of leaf numbers of fer-4 and fer-5 plants compared with WT plants. Values are the mean ± SD of at least 15 plants (**P < 0.01, one-way ANOVA with Tukey’s test). d-h Expression levels of GI (D), CO (E), FT (F), FLC (G), and SOC1 (H) transcripts in WT and fer-4 mutant plants are shown. Fourteen-day-old seedlings were grown under LD conditions and sampled and analyzed by qPCR. Day and night are denoted by white and black bars, respectively. All experiments were performed at least three times with similar results. Values are the mean ± SD (*P < 0.05, **P < 0.01, Student’s t-test). i Statistical analysis of the rosette leaf numbers at bolting in WT, fer-4 and 35S:FT/fer-4 plants grown under LD conditions. The experiments were independently repeated three times with similar results (n > 20, **P < 0.01, one-way ANOVA with Tukey’s test). j Phenotypes of WT, fer-4, fer-4/flc-3 and flc-3 grown under LD conditions. k Statistical analysis of leaf numbers of different genotypes compared with WT plants (n > 20). Error bars represent SD. The experiments were performed at least three times. Asterisks indicate a significant difference compared with WT (**P < 0.01, one-way ANOVA with Tukey’s test)