Fig. 7
PeAP1 expression pattern by in situ hybridization in P. edulis flower buds. a, b and c refer to flower buds of c.a. 0.5 cm and d, e, f, and g refer to buds of c.a. 1.5 cm in length. a Longitudinal section showing PeAP1 expression in ovary (ov), stamen (st) and in the region where the corona filaments, as well as the operculum, will develop (brackets). A magnification of this region is shown in b, where it is delimited by the bracket. The arrowhead indicates a group of cells where a corona external filament is starting to develop, and the arrow indicates the region from where the limen will emerge. c Transverse section of a flower bud showing expression of PeAP1 in sepals (se) and petals (pe). d An older flower bud, where the expression of PeAP1 is no longer present in stamen and is weak in the ovary. At this stage, the internal and external corona filaments (ic and ec, respectively), as well as the operculum (op), have initiated their growth. In e and f the cells that will form the flower nectary (ne), as well as the internal and external corona filaments (ic and ec, respectively), the operculum (op), the limen that is starting to protrude (arrow in e) maintains PeAP1 expression. g ovules (l) of flower buds of 1.5 cm still present hybridization signal. Bars: a = 50 µm; c, d = 200 µm; b, e, g, h = 100 µm