Fenologia de oito espécies de Manihot (Euphorbiaceae)

Abstract

The understanding of the phenological behavior of plants is a unique strategy for the understanding of the evolutionary mechanisms implicit in the relations with the biotic and abiotic factors. In this sense, we seek to understand the phenological behavior of eight species of Manihot, as well as the triggers for vegetative and reproductive phenophases occurring in a tropical region, in the case of northeastern Brazil. Observations were made monthly between June 2016 and May 2017, with a record of the presence and intensity of the phenophases. The signal for the manifestation of the phenomena in Manihot presented a close relation with the variation in temperature, and the climatic water availability was not shown to be primordial, among the proximal causes. The observed species presented the concentration of phenophases in the dry season, which allowed to infer a probable phylogenetic conservation of niche, because they have phenological patterns related to the climatic seasonality observed in the caatinga and cerrado biomes, regions of origin of the mentioned species. This fact may be related to the possibility of storing a significant volume of water in the trunk, probably because they have low wood density, even being cultivated in a region that presents inverse climatological conditions observed in their areas of origin. This is the first work with phenological study exclusive to the taxon. Adding knowledge to the understanding of the evolutionary history of the group.