Abstract
We evaluated the vegetative and reproductive phenological patterns of the orchids Cattleya elongata, Cyrtopodium aliciae, Epidendrum orchidiflorum, Epistephium lucidum, and Sobralia liliastrum (Orchidaceae) growing on sandstone outcrops in the Chapada Diamantina Mountains in northeastern Brazil. Phenological events were associated with abiotic factors, leaf longevity, life form, plant growth pattern, and pollination syndrome. Phenological observations were made for 18 months and followed the phenophases of: stem/pseudobulb emission, leaf flush, leaf fall, flowering, immature fruit and mature fruit. Seasonality, synchrony, and correlations between phenophases and environmental variables were tested. The orchid species demonstrated aseasonal vegetative phenologies, except for pseudobulb emission. Reproductive events were seasonal, except for flowering in E. orchidiflorum. There was high flowering overlap between the species pairs S. liliastrum and C. aliciae (dry season) and C. elongata and E. lucidum (rainy season). Dispersal occurred during both the rainy and dry seasons. The vegetative phenophases exhibited low synchrony, and were related to certain morphofunctional characters (stems/pseudobulbs, CAM metabolism). The reproductive phenophases showed high synchrony consistent with the deceit pollination strategy usually associated with the group.
Highlights
We evaluated the vegetative and reproductive phenological patterns of the orchids Cattleya elongata, Cyrtopodium aliciae, Epidendrum orchidiflorum, Epistephium lucidum, and Sobralia liliastrum (Orchidaceae) growing on sandstone outcrops in the Chapada Diamantina Mountains in northeastern Brazil
Seasonality and synchrony in plant phenology are traditionally associated with environmental variables, variations in leaf and reproductive rhythms among species occupying similar environments indicate that phenological responses may be mediated by intrinsic species attributes such as life form, plant growth pattern, leaf longevity, and dispersal and pollination modes (Williams-Linera & Meave 2002)
Considering the regional seasonality, with marked rainy and dry periods (Funch et al 2002), the relatively low availability of water in rocky mountain top microhabitats (Conceição et al 2007b), and well-known aspects of the structure and function of orchids that allow them to exploit seasonally dry habitats (Benzing et al 1982), we hypothesized that their vegetative phenology would exhibit pseudobulb/stem emissions and leaf flush during the rainy season, associated with life form, plant growth pattern, and leaf longevity; as their reproductive dynamics would be aggregate adjusted to the seasonality, and mode of pollination and wind dispersal of their seeds (Borba et al 2003; Smidt et al 2006; Spaethe et al 2007; Vale et al 2011)
Summary
Seasonality and synchrony in plant phenology are traditionally associated with environmental variables, variations in leaf and reproductive rhythms among species occupying similar environments indicate that phenological responses may be mediated by intrinsic species attributes such as life form, plant growth pattern, leaf longevity, and dispersal and pollination modes (Williams-Linera & Meave 2002). ABSTRACT We evaluated the vegetative and reproductive phenological patterns of the orchids Cattleya elongata, Cyrtopodium aliciae, Epidendrum orchidiflorum, Epistephium lucidum, and Sobralia liliastrum (Orchidaceae) growing on sandstone outcrops in the Chapada Diamantina Mountains in northeastern Brazil.
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