Regeneração natural, herbivoria e aspectos morfo-fisiológicos de Siparuna guianensis Aublet. e Inga sessilis (Vell.) Mart. Em diferentes microambientes de Floresta Estacional Semidecidual

Abstract

The Semideciduous Seasonal Forests receive this name because they lose 20 to 50% of their leaves during the dry season. They are typical formations of the Central Brazil, and they present high diversity of vegetable species with approximately 180 vascular species per hectare. However, these forests are currently found only as small fragments. The study of these remaining becomes important to better understand, and thus preserve and recover these forests. Siparuna guianensis Aublet. and Inga sessilis Vell. (Mart.) are characteristic species of such formations and present a great potential for the conservation of them and for the enrichment and the recovery of degraded areas due to their great environmental plasticity. In this study were measured the natural regeneration of these two species in two different microenvironments, natural canopy gaps and areas under closed canopy. A higher density of S. guianensis was found in canopy gaps, decreasing with the increase of these areas. The closed canopy areas and the large canopy gaps seem to present a limiting luminous condition for this species. The herbivory in these species, another factor that influences the natural regeneration, was also estimated in both microenvironments. It was found a greater herbivory rate unique and precisely in individuals of S. guianensis of canopy gaps. This difference was not explained by the nutritional quality of their leaves, which may then be explained by the greater amount of food available to this specie s herbivores in these areas (canopy gaps). Moreover, the photosynthetic responses of S. guianensis and I. sessillis were measured in different microenvironments during the dry season. The results found proved the high environmental plasticity of these species, since despite the water scarcity and the high radiation, there was no occurrence of chronic photoinhibition in selected individuals, but photosynthetic adaptations for dissipation of the excess, potentially harmful, of luminous energy. Presenting the individuals located under the canopy gaps a greater photosynthetic performance probably because they are early successional species, benefit from the conditions of this microenvironment.