Genetic structure and chemical defenses variaton in Brugmansia suaveolens (Solanaceae) / Estruturação genetica e variação de defesas quimicas em Brugmansia suaveolens (Solanaceae)

AUTOR(ES)
DATA DE PUBLICAÇÃO

2006

RESUMO

Populations patchily distributed tend to show high genetic structure and strong micro-evolutionary process evidences. Brugmansia suaveolens (Solanaceae) individuals are restrict to population patches. In this work, the genetic diversity of nine B. suaveolens populations was estimate by means of allozyme electrophoresis (chapter 1). Our results indicate high variability and genetic structure among populations. The pollinator behaviour and the hydrochoric dispersal seem determine the intrapopulation structure. There are signals that stochastic effects (i.e.: migration and foundation) affect the differentiation among populations. The most of genetic patterns found can be created by a metapopulational establishment. These populations are very susceptible to the quantitative traits differentiation, due to neutral phenotypic evolution (generated by drift) or selection action (local adaptation). To evaluate the relative action of drift and selection on population differentiation, the genetic variation in quantitative traits can be compared to neutral variation estimated by molecular markers. Four traits were evaluated in four of the B. suaveolens populations studied (chapter 2), and three of them were related to chemical defense against herbivores (tropane alkaloids concentrations). Our results show a genetic differentiation ca. three to four times higher than the differentiation estimated by molecular markers for three of characters analyzed, although no significant. The exception is ?alkaloids induction? trait, which show stabilizing selection signals (absence of interpopulation differentiation), instead of differentiation pattern expected by theory

ASSUNTO(S)

defesa quimica induzida inducible chemical defensives evolutionary mechanisms variability brugmansia suaveolens ecological genetics variabilidade brugmansia suaveolens mecanismos evolutivos genetica ecologica

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