We also conduct a global endangerment assessment based on the numbers of insular endemic plants in the endangered (EN) and critically endangered (CR) IUCN categories for 53 island groups with an estimated 9951 endemic plant species, providing a representative sample of the world's insular systems and their floristic richness. In this investigation, we use the threat factors identified by the Millennium Ecosystem Assessment as the main drivers of biodiversity loss on islands to define and rank 13 current, continuing threats to the plant diversity of nine focal archipelagos where volcanic origin (or in the Seychelles a prolonged isolation after a continental origin) has produced a high degree of endemicity and fragility in the face of habitat alteration. Effective conservation programs depend not only on protecting habitat, but also on fruit set the latter is dependent on knowledge of pollination and reproductive biology.Ĭurrent threats to the planet's biodiversity are unprecedented, and they particularly imperil insular floras. vespertilio presumably promote effective pollen transport and perhaps outcrossing. ![]() Flowers were buzz-pollinated by large-bodied native bees. Thus, the strength of andromonoecy may both affect the rate of outcrossing (genetic issues), and/or constitute a mechanism for response to the level of fruit set (physiological/ecological issues). Field observations suggest that the number of fruit developing in an inflorescence affects the gender of subsequent flowers. The species is weakly self-compatible, which may offer fertility insurance, or be remnant of the status of colonizers. The nascent expression of enantiostyly offers the opportunity for understanding its evolution. ![]() Experiments with manually deflected styles showed higher fruit set than controls. Some of these unusual features may illustrate insular release from selection, though, given the antiquity of the Canaries they likely constitute selection to promote effective sexual reproduction and outcrossing. The single large anther bears 45 % of the pollen. The style in male flowers is short to vestigial in hermaphrodites it is strongly up-turned, longer than the anthers. Anthers are heteromorphic in both sex forms, with one long upcurved and three straight shorter anthers. Flowers are tetramerous, zygomorphic, heterantherous and sometimes enantiostylous. We conducted multi-year field and laboratory studies of the sexual system and reproductive biology of Solanum vespertilio. Without full knowledge of the reproductive biology of endemic species, the chances of effective conservation decline. El abejorro endémico Bombus terrestris canariensis, en particular, fue un visitante frecuente y un vector de polen para S. Los visitantes más asiduos fueron grandes abejas y abejorros zumbadores. Ambos Solanum son andromonoi-cos: las flores con estilo largo son funcionalmente hermafroditas y proximales en las inflorescencias, mientras que las flores con estilo corto son funcionalmente masculinas y distales en la inflo-rescencia. ![]() Se registraron además los visitantes de las flores y su frecuencia. Se midieron la función masculina (desarro-llo polínico), la función femenina (iniciación de fruto) y la dispo-sición espacial de los órganos reproductivos, tanto en las flores como en las inflorescencias. ![]() Resumen Se estudiaron la polinización y biología reproductiva de dos es-pecies endémicas de las Islas Canarias: Solanum vespertilio y S. In particular, the endemic Canarian bumblebee, Bombus terrestris canariensis, was a frequent visitor and pollen vector of S. Large bees capable of buzzing were the main flower visitors. Both species of Solanum display andromonoecy: Long-styled flowers are functionally hermaphrodite and borne proxi-mally on the inflorescences, while short-styled flowers are functionally male and borne distally on inflorescences. Furthermore, we observed flower visitors and monitored visitation rates. We measured male function (pollen development), female function (fruit initiation) and spatial arrangement of reproductive parts within flowers and inflorescences. We investigated the pollination and reproductive biology of two Canary Island endemics, Solanum vespertilio and S.
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