Abstract

ALVAREZ ARNESI, Eugenio et al. Vegetative and reproductive traits of Bromelia serra (Bromeliaceae): Variations at different spatial scales and light environment effects. Ecol. austral [online]. 2019, vol.29, n.3, pp.352-364. ISSN 1667-782X.

Terrestrial bromeliads are common in neotropical forests, particularly in the understory of the Chaco woodlands, where there are dense patches of Bromelia serra growing under heterogeneous micro-environmental conditions. The light environment affects the allocation of biomass to different organs and, thus, plants that grow under different light conditions have different architecture. Furthermore, the allocation of biomass to reproductive structures is conditioned by plant size, as well as by environmental and genetic factors. To evaluate the effect of light environment on the vegetative and reproductive traits, four patches were selected from three sites separated by 500 m in the Cuña Boscosa Santafesina. At each patch, four plants were selected. Height, diameter, length and width of the longest leaf, the diameter of the infructescence, number of fruits, weight, and size of them were measured for each plant. In addition, a hemispheric photograph was taken to characterize the canopy opening. The General Linear Mixed Models showed that the proportion of variation explained by random factors (site and patches) is higher for vegetative than for reproductive traits. Most variation was recorded at the patch level for vegetative traits and at the site level for reproductive traits. The Structural Equation Modeling based on General Linear Mixed Models showed that the diameter of the infructescence was directly and indirectly affected by the light environment. The indirect effect was mediated by the smaller size of plants exposed to a larger opening canopy and by fewer and smaller fruits that resulted in smaller infructescences. These results highlight the indirect effects of light environment on reproductive traits.

Keywords : Biomass allocation; Bromeliaceae; Canopy openness; Phenotypic plasticity; Quebrachal.

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