Barbara et al. 2009 (Article) Alcantarea

Genetic relationships and variation in reproductive strategies in four closelyrelated bromeliads dapted to neotropical ‘inselbergs’: Alcantarea glaziouana, A. regina, A. geniculata and A. imperialis (Bromeliaceae)

Author(s):—T. Barbara, G. Martinelli, C.P. Silva, M.F. Fay, S. Mayo & C. Lexer

Corresponding email:—thelmabarbarakew@yahoo.co.uk

Publication:—Annals of Botany 103(1): 65-77. (2009)

Abstract:—Background and Aims Bromeliads (Bromeliaceae) adapted to rock outcrops or ‘inselbergs’ in neotropical rainforests have been identified as suitable plant models for studying population divergence and speciation duringcontinental plant radiations. Little is known about genetic relationships and variation in reproductive strategies within and among inselberg-adapted species, yet knowledge of these parameters is important for understanding divergence processes and for conservation planning.

Methods Nuclear microsatellites were used to assess the role of clonal reproduction, estimate genetic diversity and explore genetic relationships and variation in reproductive strategies for a total of 15 populations of four closely related Alcantarea inselberg species in south-eastern Brazil: A. glaziouana , A. regina, A. geniculata and A. imperialis .

Key Results Clonal propagation is frequent in coastal populations of A. glaziouana and A. regina , but absent inthe high-altitude species A. geniculata and A. imperialis . Considerable variation in clonal diversity, gene diver-sity ( H e ), allelic richness, and Wright’s inbreeding coefficient ( F is ) exists within and between species of Alcantarea . A Bayesian analysis of coastal inselberg species indicated pronounced genetic structure. A neigh-bor-joining analysis grouped populations of each species together with moderate bootstrap support, except for the high altitude species A. imperialis .

Conclusions The coastal inselberg species A. glaziouana and A. regina tend to propagate asexually via vegetative clonal growth, and both reproductive strategies and breeding systems vary greatly between populationsand species of Alcantarea . The microsatellite data indicate a history of hybridization and reticulation involvingthe high-altitude species A. geniculata and A. imperialis in areas of co-occurrence. The results highlight the need to understand similarities and differences in reproductive strategies both within and between related species for
conservation planning and as a basis for understanding evolutionary processes in tropical radiations

Keywords:—Alcantarea , Atlantic Rainforest, Bromeliaceae, clonality, gene flow, inselberg, microsatellites,reproductive strategy