Biologia floral e polinização de Anemopaegma chamberlaynii Bur. & K. Schum. (Bignoniaceae).

Abstract

The present work deals with the floral biology, reproductive system and phenological events of Anemopaegma chamberlaynii Bur. & K. Schum. (Bignoniaceae), in the coastal strand vegetation (restinga) of Maricá RJ., between 1997 and 2000. The flowers display daytime anthesis, are yellow, very attractive, tubulous, hermaphrodite, odoriferous and produce nectar as the floral reward. The nectar is secreted by a nectariferous disk and accumulated in a chamber. The stigmas are bifid, wet and papillous. The stigmatic lobes are receptive to pollen only on the inner surfaces and are sensitive to disturbance. If the stigma is touched but no pollen is deposited, the lobes close and soon reopen. The same occurs when self-pollen is deposited on the receptive surface. However, after manual pollination with cross-pollen the lobes close permanently, enabling to estimate levels of pollination by monitoring stigma closure. Euglossa cordata L., Epicharis dejeanii Lepeletier and E. semiflava Moure are potential pollinators. Xylocopa ordinaria Smith is the primary nectar robber. The species is self-incompatible and has a low fruit set (Fruit/Flower=4.86%). The flowering pattern is the “multiple bang”, showing five episodes per year, with the same intensity, all of them occurring in the most hot and rainy months.
 Keywords: Anemopaegma chamberlaynii, floral biology, reproduction, restinga, phenology.

What happens when fire is too early? Observations of fire‐stimulated fruit opening releasing underdeveloped seeds for an endemic Cerrado shrub

“…Considering the hypothesized benefits of fire‐stimulated fruit opening, we interpret our observations as the effect of a fire occurring before the fruit maturation in a shrub that is particularly susceptible to fire damage. In fact, the fruits of J. ulei are positioned within the zone of highest flame temperatures (Miranda et al, 2009; Ribeiro, 2003) and, for some seeds, the heating may have crossed the survival threshold. However, a large part of the seeds could simply be immature and not ready to germinate as fruits still had up to 2 months before regular seed dispersal.…”

“…Its individuals may grow up to 1.5 m tall and are fire-tolerant, showing strong resprouting ability after fire (plants are top-killed but resprout after a few weeks). Its dry dehiscent fruits are produced during the wet season and do not have serotiny, opening regularly every year during mid-dry season (July to early August) to release several small anemochoric seeds (Ribeiro, 2003).…”