Tissue-specific expression of OpdCYC1 and OpdCYC2 during floral development in Opithandra dinghushanensis. A-G) RNA in situ hybridizations with antisense probe of OpdCYC1C. A) Its mRNA is first detected in all five petal and stamen primordia with weak signals in lateral edges and vascular tissue of sepals. B-D) Its mRNA then weakened in two lateral stamens but strong in both dorsal and ventral staminodes with weak mRNA in the ring meristem of corolla-tube. C-D) Successive sections from the same individual flower across base (C) and upper parts (D) of stamens. E-F) Its expression shifts to peripheries and becomes undetectable in two enlarged lateral stamens while remains strong in dorsal and ventral staminodes. G) Its mRNA is undetectable in stamens as pollen sacs begin development. H-L) RNA in situ hybridizations with antisense probe of OpdCYC2A. H) Its dense transcript accumulation first restricted to the dorsal side of the floral apex (arrow). I-K) Its strong expression then restricted to two dorsal petals and the dorsal staminode as they are initiated. Note its mRNA later becomes restricted to the dorsal-most parts in two dorsal petals (K). L) Its mRNA is undetectable in stamens as pollen sacs begin development. OpdCYC1D (M) and OpdCYC2B (N) mRNA is not detected in floral tissues. As a negative control, RNA in situ hybridizations with sense probes of OpdCYC1C (O) and OpdCYC2A (P) detect no signal in floral tissues. dp, dorsal petal; ds, dorsal sepal; dt, dorsal staminode; g, gynoecium; lp, lateral petal; ls, lateral sepal; lt, lateral stamen; vp, ventral petal; vs, ventral sepal; vt, ventral staminode. Scale bars, 150 μm.