Abstract

RAIMUNDEZ U, Elena  and  RAMIREZ, Nelson. Estrategia reproductiva de una hierba perenne: Hypoxis decumbens (Hypoxidaceae). Rev. biol. trop [online]. 1998, vol.46, n.3, pp.555-565. ISSN 0034-7744.

The reproductive strategy of Hypoxis decumbens L. (Hypoxidaceae), a perennial herb with hermaphroditic flowers, was studied to check the relations between reproductive system, life form, habitat, pollination system and other morphological and ecological features. The study was done in a secondary deciduous forest with a population of 150-200 plants. Controlled pollinations were done in twenty isolated plants. The results pointed out that H. decumbens is an autogamous species, with outbreeding depression apparently reflecting environmental adaptation of the autogamous genotypes. The main pollinators were generalist insects, like dipterans. It has functionally solitary and actinomorphic flowers, with well exposed floral parts, displayed approximately at the same height, and with inner and before anthesis dehiscence of the anthers. The biomass allocation was mainly to female structures, like fruits and seeds, which was reflected in a low male-female biomass ratio, and in high fruit and seed set. The pollen-ovule and the attraction-support biomass ratios were low, associated with autogamous species, which have reliable pollination. The dispersal unit is the seed and the dispersal syndrome is myrmecochory, with the infructescence prostrate over the soil, the fruit with gradual dehiscence and with lipid droplets and placental remains (also with lipid content) in the seed coat. This species has several structural and functional attributes that sustain a mixed mating system and, although the results indicate that most of the progeny is autogamous; it does not sacrifice the opportunity for out-crossing.

Keywords : Hypoxys decumbens; perennial herb; mixed mating system; autogamy; outbreeding depression; pollination; fruit; seed set; biomass; allocation.