Fig. 3. Expression analyses of PapsAP3 and PapsPI genes. (A) mRNA in situ hybridization analyses for PapsAP3-1, PapsAP3-2, PapsPI-1 and PapsPI-2 during P3 to P5 stages of poppy flower development. Light micrographs of representative stages are shown. Black arrow, petal primordia; red arrow, carpel primordia. PapsAP3-1 is expressed in petal and stamen primordia commencing at stage P3, and is maintained in these organs through later stages. This is in contrast to PapsAP3-2 expression, which is initially restricted to the stamen primordia; later, PapsAP3-2 expression expands to include developing petals at stage P5. PapsPI-1 expression commences in petal and stamen primordia at stage P3, and is maintained in this pattern through later stages. PapsPI-2 expression is weak but detectable in petal, stamen and carpel primordia at stage P3; by stage P5, expression is predominantly in stamens and on the adaxial side of the carpels. Scale bar: 200 µm, for all panels. (B) RT-PCR analyses of PapsAP3 and PapsPI expression during stages P6 to P8 of poppy flower development (as shown above). At each stage, sepals (se), petals (pe), stamens (st) and carpels (ca) were removed separately for analysis. The P. somniferum actin gene (PapsACT1) was used as an amplification control.