Chromosome studies in Orchidaceae from Argentina, II

GRABIELE, M.; CERUTTI, J. C.; HOJSGAARD, D. H.; ALMADA, R. D.; DAVIÑA, J. R.; HONFI, A. I.

TAXON

INT ASSOC PLANT TAXONOMY

Lugar: Viena; Año: 2010

0040-0262

Nine species of five genera of spiranthoid orchids from NE Argentina were chromosomally studied. In all the cases, the chromosome number is 2n=2x=46. Pelexia lindmanii Kraenzl (42m+4sm), P. bonariensis (Lindl.) Schltr. (36m+10sm), P. ekmanii (Kraenzl) Schltr. (36m+10sm), Sarcoglottis fasciculata (Vell.) Schltr. (32m+12sm+2st), S. grandiflora (Hook.) Klotzsch (32m+12sm+2st), S. ventricosa (Vell.) Hoehne (32m+12sm+2st), Mesadenella cuspidata (Lindl.) Garay (38m+8sm), Sacoila lanceolata (Aubl.) Garay (38m+8sm) and Skeptrostachys paraguayensis (Rchb. f.) Garay (38m+8sm) also share bimodal and symmetrical karyotypes, with similar mean chromosome lengths (1.85±0.15µm) and comparable genome sizes (42.43±3.49µm), features that support their inclusion within the subtribe Spiranthinae. These novel cytological evidences also sustain the division of Spiranthinae in less rank clades, with Mesadenella Pabst & Garay, Sacoila Raf. and Skeptrostachys Garay in a group and Pelexia Poitier ex Lindley and Sarcoglottis Presl. segregating to another one, in agreement with preceding morphological and molecular data. The observed karyotype features similarities, being more evident for Sarcoglottis and the group of Mesadenella, Sacoila and Skeptrostachys, can be explained in terms of karyotype orthoselection processes.