Bromeliaceae is a morphologically distinctive and ecologically diverse family originating in the New World. Three centers of diversity, 58 genera, and about 3,140 bromeliad species are currently recognized. We compiled all of the studies related to the reproductive biology, genetic diversity, and population structure of the Bromeliaceae, and discuss the evolution and conservation of this family. Bromeliads are preferentially pollinated by vertebrates and show marked variation in breeding systems, from predominant inbreeding to predominant outcrossing, as well as constancy in chromosome number (2n = 2x = 50). Autogamous or mixed mating system bromeliads have a high inbreeding coefficient (FIS), while outcrossing species show low FIS. The degree of differentiation among populations (FST)of species ranges from 0.043 to 0.961, which can be influenced by pollen and seed dispersal effects, clonal growth, gene flow rates, and connectivity among populations. The evolutionary history of the Bromeliaceae is poorly known, although some studies have indicated that the family arose in the Guayana Shield roughly 100 Mya. We believe that genetic, cytogenetic, and reproductive data will be essential for diagnosing species status and for assisting conservation programs.
Seed dispersal, population structure and the mating system of plant species can have great consequences on the genetic structure of populations. Vriesea gigantea is a bromeliad from southeastern Brazil which is self-compatible and pollinator dependent for fruit set. Its populations are fertile in terms of the production of flowers, pollen, fruits and seeds. To assess the importance of seed supply for gene flow, colonization and distribution of adult individuals, the seed dispersal and population structure of V. gigantea were studied. Seeds are dispersed over short distances; most seeds land close to the mother plant. This pattern coincides with the reported aggregate distribution of bromeliad seedlings. Population structure results showed high seedling recruitment, because 51.3% developed into adults, although few juveniles reached this stage. This result is different from that for other bromeliad species from different habitat conditions. Seed dispersal and population structural patterns are consistent with previous molecular studies, revealing that V. gigantea populations are genetically structured, with low gene flow and a moderate outcrossing rate. Barbará T, Martinelli G, Palma-SilvaC, Fay MF, Mayo S, Lexer C. 2009. Genetic relationships and variation in reproductive strategies in four closely related bromeliads adapted to neotropical 'inselbergs': Alcantarea glaziouana, A. regina, A. geniculata and A. imperialis (Bromeliaceae). Annals of Botany 103: 65-77. Bennett BC. 1986. Patchiness, diversity, and abundance relationships of vascular epiphytes. Selbyana 9: 70-75. Bennett BC. 1991. Comparative biology of Neotropical epiphytic and saxicolous Tillandsia species: population structure. Journal of Tropical Biology 7: 361-371. Benzing DH. 1978. Germination and early establishment of Tillandsia circinnata Schlecht. (Bromeliaceae) on some of its hosts and other supports in southern Florida. Selbyana 2: 95-106. Benzing DH. 1981. Bark surfaces origin and maintenance of diversity among angiosperm epiphytes: a hypothesis. Selbyana 5: 248-255. Benzing DH. 1990. Vascular epiphytes: general biology and related biota. Cambridge: Cambridge University Press. Benzing DH. 2000. Bromeliaceae: profile of an adaptive radiation. Cambridge: Cambridge University Press.Bittencourt JVM, Sebbenn AM. 2007. Patterns of pollen and seed dispersal in a small, fragmented population of the wind-pollinated tree Araucaria angustifolia in southern Brazil. Heredity 99: 580-591. Borges LA, Sobrinho MS, Lopes AV. 2009. Phenology, pollination, and breeding system of the threatened tree Caesalpinia echinata Lam. (Fabaceae), and a review of studies on the reproductive biology in the genus. Flora 204: 111-130. Brown AHD. 1990. Genetic characterisation of plant mating system. In: Brown AHD, Clegg MT, Kahler AL, Weir BS, eds. Plant population genetics, breeding and genetic resources. Sunderland, MA: Sinauer Associates, 145-162. Bullock JM, Clarke RT. 2000. Long distance seed dispersal by wind: measuring and modeling the tail of the curve. Oecologia 124:...
Studies on interspecific gene flow and hybridization are important for understanding speciation processes and the movement of genes across species boundaries. In sympatric areas, hybridization between closely related species can be a common phenomenon and the degree of reproductive isolation (RI) among these species is closely related to the probability of hybrid formation. Here, using 14 nuclear microsatellites and two plastid DNA regions, we investigated the occurrence of natural hybridization in four sympatric populations of Vriesea carinata and V. incurvata. We also analysed four allopatric populations (two from each species), totalling 272 samples. These species share pollinators and have sequential flowering with a short period of overlap. Based on genetic assignment tests, 17 hybrids were detected in two of the four sympatric populations studied (8.29% of the individuals sampled). Our results showed low levels of nuclear (F ST = 0.098) and high plastid genetic differentiation (F ST = 0.601), with no haplotype sharing between parental species. The presence of plastid DNA haplotypes of both parental species in the hybrids indicated that hybridization probably occurred in both directions. We identified few hybrids, probably in consequence of some degree of RI between these species. Several RI barriers may be acting to maintain species integrity, temporal flowering differences being one important factor.
Epiphytes are hyper‐diverse and one of the frequently undervalued life forms in plant surveys and biodiversity inventories. Epiphytes of the Atlantic Forest, one of the most endangered ecosystems in the world, have high endemism and radiated recently in the Pliocene. We aimed to (1) compile an extensive Atlantic Forest data set on vascular, non‐vascular plants (including hemiepiphytes), and lichen epiphyte species occurrence and abundance; (2) describe the epiphyte distribution in the Atlantic Forest, in order to indicate future sampling efforts. Our work presents the first epiphyte data set with information on abundance and occurrence of epiphyte phorophyte species. All data compiled here come from three main sources provided by the authors: published sources (comprising peer‐reviewed articles, books, and theses), unpublished data, and herbarium data. We compiled a data set composed of 2,095 species, from 89,270 holo/hemiepiphyte records, in the Atlantic Forest of Brazil, Argentina, Paraguay, and Uruguay, recorded from 1824 to early 2018. Most of the records were from qualitative data (occurrence only, 88%), well distributed throughout the Atlantic Forest. For quantitative records, the most common sampling method was individual trees (71%), followed by plot sampling (19%), and transect sampling (10%). Angiosperms (81%) were the most frequently registered group, and Bromeliaceae and Orchidaceae were the families with the greatest number of records (27,272 and 21,945, respectively). Ferns and Lycophytes presented fewer records than Angiosperms, and Polypodiaceae were the most recorded family, and more concentrated in the Southern and Southeastern regions. Data on non‐vascular plants and lichens were scarce, with a few disjunct records concentrated in the Northeastern region of the Atlantic Forest. For all non‐vascular plant records, Lejeuneaceae, a family of liverworts, was the most recorded family. We hope that our effort to organize scattered epiphyte data help advance the knowledge of epiphyte ecology, as well as our understanding of macroecological and biogeographical patterns in the Atlantic Forest. No copyright restrictions are associated with the data set. Please cite this Ecology Data Paper if the data are used in publication and teaching events.
Inbreeding depression is a reduction of fitness in the progeny of closely related individuals and its effects are assigned to selfing or biparental inbreeding. Vriesea gigantea is a self‐compatible bromeliad species distributed in the Brazilian Atlantic rainforest and habitat destruction and fragmentation and collection have decreased the natural populations. We aim to describe the occurrence of inbreeding depression (δ) in three natural populations of V. gigantea and to correlate this phenomenon with previous studies of fertility, genetic diversity, population genetic structure, gene flow, mating system and seed dispersal in this species. Fifty‐four adult plants were sampled and 108 flowers were used for pollination treatments (selfing, outcrossing and control). For adult plants, we analysed plant and inflorescence height, flower numbers and seed set. In the progenies, evaluated parameters included seed germination and seedling survival rate. The results indicated low to moderate levels of inbreeding depression in V. gigantea (δ = 0.02 to 0.39), in agreement with molecular data from a previous study. Vriesea gigantea populations tolerate some degree of inbreeding, which is consistent with previous results on fertility, mating system, genetic diversity and gene flow. © 2012 The Linnean Society of London, Botanical Journal of the Linnean Society, 2012, 169, 312–319.
Aechmea subgenus Ortgiesia comprises ca. 20 species distributed in Brazil, Argentina, Paraguay, and Uruguay, with a center of diversity in the Brazilian Atlantic rainforest. We examined interspecific relationships of Ortgiesia based on Amplified Fragment Length Polymorphisms (AFLP). Ninety-six accessions belonging to 14 species of Ortgiesia were sampled, and genotyped with 11 AFLP primer combinations. The neighbor joining (NJ) tree depicted two main genetic groups within Aechmea subgenus Ortgiesia, and four subgroups. The NJ tree showed short internal branches, indicating an overall shallow genetic divergence among Ortgiesia species as expected for the recently radiated subfamily Bromelioideae. Our results suggest that hybridization and/or incomplete lineage sorting may have hampered the reconstruction of interspecific relationships in Aechmea subgenus Ortgiesia. The mapping of petal color (yellow, blue, pink, or white), inflorescence type (simple or compound), and inflorescence shape (ellipsoid, subcylindric, cylindric, or pyramidal) against the NJ tree indicated that these characters are of limited taxonomic use in Aechmea subgenus Ortgiesia due to homoplasy. An analysis of the current distribution of Ortgiesia identified the southern region of the Brazilian Atlantic rainforest, between latitudes of 26° and 27°S, as the center of diversity for the subgenus.
We hypothesized that incomplete lineage sorting and localized hybridization events are responsible for the low levels of genetic differentiation and the taxonomic complexity observed among and within the seven yfAsO species. Further studies on and will be necessary to clarify the boundary between these two species. Most of the populations sampled showed high genetic diversity and/or unique haplotypes; they should be prioritized for conservation purposes.
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