Genetic, morphological and spatial characterization of two populations of Mabea fistulifera Mart. (Euphorbiaceae), in different successional stages

Abstract

ABSTRACT

Contrasting genetic diversity and differentiation of populations of two successional stages in a Neotropical pioneer tree (Eremanthus erythropappus, Asteraceae)

“…The two indices used to estimate within population diversity in the two successional stages were concordant, and none indicated differences in degree of genetic diversity between populations from "candeial" and populations from forest. These results do not support the hypothesis that the selection of genotypes during succession leads to genetic depletion (Gray, 1987), but they are in accordance with several other studies indicating that populations maintain equal levels of intra-populational genetic diversity during succession (Aarssen and Turkington, 1985;Hartnett et al, 1987;Peroni, 1994;Pluess and Stöcklin, 2004;Solé et al, 2004;Goulart et al, 2005;Raffl et al, 2006). These results suggest that if an increase in selection intensity occurred during succession it did not result in a decrease in genetic diversity or that the selection effect was balanced by other factors, such as gene flow.…”

“…The Shannon index of diversity (H O ) was estimated from the frequencies of the RAPD bands within each population and also over all populations. The equation used was: H = -Σ p i log 2 p i , where p i was the frequency of the presence or absence of the band (Lacerda et al, 2001;Goulart et al, 2005). The among-population diversity component was calculated as (H SP -H POP ) / H SP , where H SP is the total diversity, i.e., the diversity of all populations together and H POP the mean withinpopulation diversity value.…”

“…The Shannon indexes (0.382 to 0.487) were higher than in Plathymenia reticulata (0.301 to 0.367; Lacerda et al, 2001), Mabea fistulifera (0.383 and 0.405; Goulart et al, 2005) and Hymenaea courbaril and H. stigonocarpa which showed average diversity of populations of 0.301 and 0.321 (H POP ), respectively (Brandão, 2002). The percentage of polymorphic fragments found in populations of E. erythropappus (54.5 to 70.7%) was also higher than in populations of P. reticulata (41.7 to 55.6%; Lacerda et al, 2001), M. fistulifera (49.0 to 56.0%; Goulart et al, 2005), H. courbaril (37.7 to 47.8%), and H. stigonocarpa (44.1 to 48.5%) (Brandão, 2002). On the other hand, the diversity values found here are similar to that found in two other populations of E. erythropappus of other sites (Shannon indexes = 0.45 and 0.49; Estopa et al, 2006), which suggests that high diversity is a characteristic of this species.…”

“…During a successional process, some pioneer long-lived species can remain in the community even after temporal changes in species composition (Pluess and Stöck-lin, 2004;Goulart et al, 2005;Litrico et al, 2005). These species provide an interesting model to study ecological and genetic changes that occur during succession.…”

An efficient and rapid DNA minipreparation procedure suitable for PCR/SSR and RAPD analyses in tropical forest tree species

“…RAPD (Random Amplified Polymorphic DNA) involve the use of a single 'arbitrary' primer. Regardless of its dominant nature and reproducibility problems, the technique has been widely used in many plant population genetic studies due to its high potential to detect the polymorphism (Gillies et al, 1997;Torezan et al, 2005;Goulart et al, 2005). Because these studies require the analysis of large populations, a DNA extraction method, which could be fast, inexpensive and yielding high quality DNA, is required.…”