La Tour du Valat

Institut de recherche pour la conservation des zones humides méditerranéennes

Titre :	Cytogeography of the South American Turnera sidoides L. complex (Turneraceae, Leiocarpae)
Auteurs :	Viviana G. Solís Neffa, Auteur ; Aveliano Fernández, Auteur
Type de document :	Article
Dans :	Botanical Journal of the Linnean Society (137(2) 2001-10-01)
Article en page(s) :	189-196
Résumé :	New chromosome number determinations are presented for 48 populations of five subspecies of Turnera sidoides. Chromosome counts in sspp. carnea, holosericea, integrifolia and sidoides confirm previous data while, in ssp. pinnatifida, the numbers 2n=2x = 14 and 2n = 6x = 42 are reported for the first time. The results show that polyploidy is a very frequent phenomenon. Populations are primarily tetraploids (2n = 4x = 28), while diploids (2n = 2x = 14), hexaploids (2n = 6x = 42) and octoploids (2rc = 8x = 56) are less frequent. Diploid, tetraploid and hexaploid cytotypes occur in sspp. carnea and pinnatifida, whereas tetraploids and hexaploids are known in ssp. holosericea. Turnera sidoides ssp. integrifolia shows a polyploid series with ploidy levels from 2x to 8x. The ssp. sidoides appears to be uniformly tetraploid, with the exception of an isolated pentaploid (2rc = 5x = 35). On the basis of these counts and previous reports the geographical distribution of the cytotypes has been determined and related to climatic and ecological factors.
En ligne :	https://doi.org/10.1111/j.1095-8339.2001.tb01115.x

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