Pollinarium size as a hybridisation barrier between sympatric inter-compatible orchids

Autor(es)

Vieira, B. C. ^[1] ; Pansarin, L. M. ^[2] ; Martucci, M. E. P. ^[3] ; Gobbo-Neto, L. ^[3] ; Pansarin, E. R. ^[1]

Afiliação do(s) autor(es)

^[1] Univ Sao Paulo, Fac Filosofia Ciencias & Letras, Dept Biol, BR-14040901 Ribeirao Preto, SP - Brazil

^[2] Univ Sao Paulo, Inst Biociencias, Dept Ecol, Rua Matao 321, Trav 14, BR-05508900 Sao Paulo, SP - Brazil

^[3] Univ Sao Paulo, Fac Ciencias Farmaceut Ribeirao Preto, Av Cafe S-N, BR-14040903 Ribeirao Preto, SP - Brazil

• Tipo de documento: Artigo Científico
• Fonte: Australian Journal of Botany; v. 65, n. 6-7, p. 497-506, 2017.
• Citações Web of Science: 3

Resumo

Hybridisation has been recorded for many different organisms, including plants, and is crucial in the diversification of Epidendrum, a neotropical orchid genus with similar to 1500 species. Based on the evidence of frequent natural hybridisation in Epidendrum and the absence of pre-mating barriers among the species, our main hypothesis was that pollen transfer is occurring between two sympatric species, Epidendrum secundum Jacq. and Epidendrum denticulatum Barb. Rodr. The reproduction of the species was investigated based on morpho-anatomical and histochemical analyses and intra-and interspecific crosses. Also, the relationship between co-occurring species was verified by floral morphometry, principal component analysis and sequence divergence analyses. Results showed that E. secundum and E. denticulatum are rewardless, self-and inter-compatible, and need a biotic vector for pollen transfer. Although there is inter-compatibility among the species, and E. secundum and E. denticulatum share the pollinators, our data showed no intermediary forms in either morphology or molecular data. All data collected suggest that, at least nowadays, no gene flow is occurring, and that hybridisation has been avoided due to the incompatible pollinarium size between the sympatric E. secundum and E. denticulatum, which acts as a pre-mating barrier in the studied population. This new discovery increases the knowledge about the isolation mechanisms and pre-pollination barriers in plants. (AU)

• Processo FAPESP: 13/24683-0 - Biologia reprodutiva de Epidendrum martianum Lindl. (Orchidaceae: Laeliinae)
• Beneficiário: Bruno César Vieira
• Modalidade de apoio: Bolsas no Brasil - Iniciação Científica
• Processo FAPESP: 12/13522-2 - Biologia floral e investigação da ocorrência de hibridação natural entre Epidendrum secundum e E. denticulatum no Cerrado de Itirapina - SP
• Beneficiário: Bruno César Vieira
• Modalidade de apoio: Bolsas no Brasil - Iniciação Científica