IBONE   05434
INSTITUTO DE BOTANICA DEL NORDESTE
Unidad Ejecutora - UE
congresos y reuniones científicas
Título:
Basic chromosome number implication in the relationship between two series of Turnera (Passifloraceae, Turneroideae) with floral nectariferous pockets
Autor/es:
SILVIA ANDREA FERNÁNDEZ; MARÍA MERCEDES ARBO; AVELIANO FERNÁNDEZ
Lugar:
Foz de Iguazu
Reunión:
Conferencia; 21st International Chromosome Conference (ICC).; 2016
Institución organizadora:
International Chromosome and Genome Society
Resumen:
The genus Turnera is structured in 11 series: Annulares, Anomalae, Capitatae, Conciliatae, Leiocarpae, Microphyllae, Papilliferae, Salicifoliae, Sessilifoliae, Stenodictyae and Turnera, with two subseries: Turnera and Umbilicatae. The flowers of series Anomalae and Turnera are the only ones that have nectariferous pockets. In this genus, three basic chromosome numbers were found: Series Leiocarpae, Microphyllae, Salicifoliae and Stenodictyae have x=7; series Papilliferae has x=13, and series Turnera has x=5. In the first molecular analysis of the genus, T. cearensis (from the series Anomalae) clustered with T. calyptrocarpa of Series Microphyllae (x=7). However, according to a cladistic analysis based on morphological characters and basic chromosome numbers, series Turnera and Anomalae could be sisters. Hence, the cytogenetic analysis of T. cearensis would clarify the position of series Anomalae. For the mitotic analysis we stained roots with the Feulgen technique, and for the meiotic analysis we stained anthers from fresh and fixed buds with acetic orcein. We found in mitosis the chromosome number 2n=30, and in meiosis 16 cells with 15 II, one cell with 13 II+1 IV and 74 cell with 12 II + 1VI, all of them with basic number x=5. The discovery of x=5 in series Anomalae is a crucial information to find the actual position of this series in the genus. The evidence suggests that basic chromosome number and floral morphology could be linked, and this is a strong argument in favour of the merger of the series Anomalae and Turnera. Experimental crosses between T. cearensis, T. calyptrocarpa and species of Series Turnera would help to clarify this situation.