Floral biology and potential hybridization of three sympatric epiphytic bromeliads in Veracruz, Mexico

• Published in: Plant species biology Vol. 35; no. 3; pp. 197 - 209
• Main Authors: Ramírez‐Rosas, Kareen, Aguirre‐Jaimes, Armando, Ramírez‐Morillo, Ivón M., García‐Franco, José G.
• Format: Journal Article
• Language: English
• Published: Melbourne John Wiley & Sons Australia, Ltd 01.07.2020
• Subjects: fruit and seed set; interspecific crosses; intraspecific crosses; seed germination; Tillandsia species
• ISSN: 0913-557X; 1442-1984
• DOI: 10.1111/1442-1984.12279

In the Bromeliaceae, hybrids have been engineered for horticultural purposes; in addition, hybrids have been observed in natural habitats. We investigated the hybridization potential of three sympatric species of Tillandsia inhabiting secondary forests and shaded coffee plantations in the central mountains of Veracruz, Mexico. The studied species (T. juncea, T. polystachia and T. variabilis) show overlap in flowering phenology and are believed to share pollinators. We compared the floral morphology of the species, performed controlled intra‐ and interspecific pollinations, and recorded pollen tube growth, fruit and seed set, as well as seed germination. Flower size differed among the species, but stamen and stigma heights were similar between pairs of species, which would facilitate interspecific pollen exchange. Pollen tubes reached the ovary in interspecific crosses. The three species showed interspecific cross‐compatibility, as all crosses resulted in development of mature fruit and viable seeds. Tillandsia juncea achieved the highest fruit set, whereas T. variabilis showed the highest seed set. Seed set as a result of agamospermy, autogamy, geitonogamy and interspecific cross‐pollination did not differ among the species. The findings suggest that pre‐ and post‐pollination barriers are weak among the three species of Tillandsia, which thus could potentially hybridize in natural sympatric populations. The species studied have a mixed‐mating system and also have the potential to produce hybrids.the mixed‐species clumps, flowering overlapped, and the similarity in the pistil and stamen length can facilitate the transfer or reception of the pollen each other.The interbreeding potential varies depending on the species role as pollen donors or recipients.