A, Developmental stages of floral buds and spikes are described in Fig 1. B, PaFD expression in a developing spike by in situ hybridization. The magnified axillary floral meristem in the emerging spike (≤ 3 cm in length) is in the box (left panel) and the middle panel is a negative control with a sense probe. PaFD transcript was detected in the floral meristems in the developing spike (3–10 cm in length, right panel). Bar is 100 ìm. C, Expression pattern of PaFD in different developmental stages. The stage 1 (S1) is 16-month and the S2 is 20-month old stages of the orchid in the flasks. S3 and S4 show 26-month and 34-month old stages of the orchid in the pots, respectively. Bar is 1 cm. D, Flowering phenotypes of wild type, fd mutant (fd-3), and two independent homozygous transgenic plants expressing PaFD under the control of Arabidopsis FD promoter in fd-3 background. E, Flowering time of the each genotype shown in D. Twelve individuals for each genotype were used for flowering time measurement and PaFD expression is detectable only in the transgenic plants.