Reproductive biology of duodichogamous Koelreuteria elegans (Sapindaceae): the rare case of a female?male?female flowering sequence

LATTAR E.C.; ÁVALOS, A.A.; ÁVALOS, A.A.; TORRETA, J.P.; TORRETA, J.P.; FERRUCCI M.S.; FERRUCCI M.S.; LATTAR E.C.

AUSTRALIAN JOURNAL OF BOTANY

CSIRO PUBLISHING

Lugar: Collingwood; Año: 2019 vol. 67 p. 149 - 158

0067-1924

Monoecious species are common within Sapindaceae, andamong them a large variation in sexual expression has been reported. In thiswork we evaluate the sexual expression, phenology, floral biology, and matingsystem in eight to sixteen individuals of the duodichogamous Koelreuteriaelegans (Seem.) A.C. Sm. subsp. formosana (Hayata) F.G. Mey. Results from ourstudy show that all individuals exhibited a pattern of flowering characterisedby two cycles of pistillate flowers with an intervening one of staminateflowers. The synflorescences presented a high synchronisation between the maleand female phases at the individual level. Therefore, very little functionaloverlap was observed between pollen receipt and pollen dispatch withinindividuals. Pollination was by bees, and the manual pollination experimentsshowed that this species is a xenogamous although self-compatible species.Nevertheless, seed set increased significantly with hand crosspollination andopen pollination experiments. Decrease of fruits and seeds set by geitonogamycould favour the establishment of duodichogamy with interfloral protogynypromoting cross-pollination. In the family this is the first report of apattern of flowering in which there are two cycles of female with anintervening cycle of male flowers. The importance of detailed these studies forunderstanding mechanisms underlying duodichogamy was demonstrated, and findingswill help to broaden our understanding about this rare sexual system togeneralise the specific ecological factors that explain its evolutionarymeaning.