Reproductive biology and pollination of Palicourea crocea (Rubiaceae), the distylous and ornithophilous specie in the Cerrado of Goiás, Brazil

Abstract

The heterostyly is a floral polimorphysm genetically controlled where populations of plants present two or three morphs with reproductive structures in reciprocal heights among the morphs. In natural populations, a balanced ratio between morphs (isoplethy) is expected. The objective of the study was to characterize the breeding system, the floral biology, the characteristics of heterostyly, including reciprocity of reproductive parts, the phenology and pollination in Palicourea crocea, a shrub species of the understory of forest formations of Cerrado. For such measures were floral structures, held controlled crossings, observed flower visitors, in addition to phenological monitoring. Palicourea crocea is proved to be a typical distylous species, self-incompatible, with high levels of reciprocal herkogamy between the morphs. Preferentially pollinated by hummingbirds, followed by moths and bees. There was a higher fruit formation in cross-pollination intermorph (> 50%) and lower fruit formation intramorph pollination (< 20%), and self-pollination (< 13%). These data were confirmed by the not growth of pollen tubes in self-pollination and pollinated intramorph pistils. Flowering is annual and occurs between the months of November and February, with peak flowering in December and January. Reproductive data evaluated to show similar to other species of Rubiaceae of the understory of forest formations of Cerrado.

Key words:
hummingbirds; Cerrado; Rubiaceae; heterostyly