SOLIS NEFFA Viviana Griselda
cpDNA variation in the Turnera sidoides L. complex (Turneraceae): biogeographical implications
SPERANZA, P. R.; GRELA, I.; SEIJO, J. G.; VIVIANA GRISELDA SOLIS NEFFA
JOURNAL OF BIOGEOGRAPHY
WILEY-BLACKWELL PUBLISHING, INC
Año: 2007 vol. 34 p. 427 - 427
Aim To analyse the current geographical structure of cpDNA variation in the Turnera sidoides L. complex to establish historical biogeographical hypotheses for the mid-latitude South American lowlands. During the Quaternary, its climate has shifted from tropical humid to cold dry and its vegetation cover has not been stable. The consequences of these processes on the current distribution of the vegetation of this area have received very little attention. Location The mid-latitude South American lowlands extend approximately between 20º and 40ºS and include Uruguay, northern, central and eastern Argentina, southern Brazil, and parts of southern Paraguay and Bolivia and it is surrounded by higher elevation systems. Methods Turnera sidoides is a well studied polyploid complex of perennial rhizomatous herbs occurring throughout the area of interest. We analyzed 321 individuals from 79 populations of the five recognized subspecies. We also included progenies from artificial crosses to analyze chloroplast inheritance. After screening sequences for four non-coding chloroplast DNA regions, the trn - trnF spacer was selected to characterize the collection. Results Three haplotypes can be easily identified, which each differ from one another in two independent characters. A clear geographic structure is revealed when haplotypes are plotted for the complex as a whole regardless of subspecies and cytotype. Three distinct regions may be identified. Main conclusions We propose three putative refugial areas for the Turnera sidoides complex, associated with the orographical systems of the region. Ravines and slopes in the Haedo Cuchilla system in Northern Uruguay, the elevations of the western side of the area in Argentina, and the Eastern Serranías system in southeastern Uruguay, may each have served as refugia in which the A, B and C haplotypes became fixed during the drier climatic phases. Biogeographical patterns in the area covered by T. sidoides, particularly east of the Uruguay River, have not previously been analyzed from a historical perspective.