Fertility of Vriesea gigantea Gaud. (Bromeliaceae) in southern Brazil

Abstract

Plant fertility is a central subject of many questions in plant evolutionary and conservation biology. Pollen availability, abiotic resources, and flowering pattern can limit fruit and seed production. Open pollination and pollen supplementation studies are used to estimate any pollen limitation in natural populations. To study the impact of these factors on the reproductive success of Vriesea gigantea, an epiphytic bromeliad in the Atlantic Rainforest in Brazil, its fertility in four natural populations in Itapuã State Park was assessed by considering plant and inflorescence size, flower production, fruit and seed set, flower and fruit set pattern, and seed viability and germination rate. Supplemental pollination in adult plants was used to determine whether fruit production in V. gigantea is limited by reception of pollen. The results showed that V. gigantea has a high production of flowers, fruits, and seeds. Seeds are highly viable in all populations, presenting an average germination rate of 94% (SE ± 3.5). Plants of V. gigantea from Itapuã State Park are highly fertile. The high proportion of fruit and seed set after manual hand pollination indicates that the species is self-compatible. Pollination treatments showed evidence of pollinator limitation in the Itapuã State Park population.

Reproductive biology and pollination of Aechmea distichantha Lem. (Bromeliaceae)

“…Th e larger production of fruits and seeds may be also aff ected by pollinator behavior since bromeliads in sunny places were visited more oft en. Pollinator foraging may be infl uenced by the environmental light (Kilkenny & Galloway, 2008) and pollen limitation due to reduced pollinator visits may cause the variation in reproduction among bromeliad populations (Paggi et al 2007). Since hummingbirds are very sensitive to environmental changes in resource supply (Cotton 2007) and avoid unrewarding patches (Sandlin 2000), they may have visited the bromeliads in sunny patches more oft en due to greater fl ower availability.…”

“…Selfi ng has been found in most species and in several genera, including Aechmea, Alcantarea, Billbergia, Canistrum, Pitcairnia and Vriesea (Martinelli 1997;Siqueira Filho & Machado 2001;Wendt et al 2001;Wendt et al 2002;Lenzi et al 2006;Paggi et al 2007), yet incompatibility systems are also found in Aechmea, Billbergia and Quesnelia (Martinelli 1997;Canela & Sazima 2003). Spatial and temporal mechanisms to avoid selfi ng include dichogamy, dioecy and herkogamy (Martinelli 1997;Siqueira Filho & Machado 2001).…”

“…Environmental variation may also infl uence fi tness by aff ecting the number and abundance of pollinating species (Herrera 1995). In the Bromeliaceae, environmental variation can infl uence reproductive success within and among populations (Paggi et al 2007). For example, light regime can infl uence individual size and consequently their reproductive success (Lenzi et al 2006).…”

Range-wide patterns of nuclear and chloroplast DNA diversity in Vriesea gigantea (Bromeliaceae), a neotropical forest species

“…Recently, we have started to use species of the closely related genera, Vriesea and Alcantarea, for studies of the genetic underpinnings of adaptive radiation in the Tillandsioideae subfamily of Bromeliaceae. These two genera have diversified into multiple species adapted to life in continuous forest or on granitic 'inselberg' rock outcrops in the South American Atlantic Rainforest (Barbará et al, , 2008Paggi et al, 2007;Palma-Silva et al, 2007). This study provides vital genetic and phylogeographic data to inform ongoing studies on the genetics of population divergence and speciation in this group.…”

“…1600 km between the Brazilian states of Rio Grande do Sul (RS) and Espírito Santo (ES) (Figure 1; Smith and Downs, 1977). The species has a mixed-mating system (Paggi et al, 2007) with bat pollination (Sazima et al, 1999) and wind-based seed dispersal. Its populations are generally large and composed of patches of different sizes and densities.…”