Comportamento fenológico de três espécies de Jatropha (Euphorbiaceae) da Caatinga, semi-árido do Brasil

Abstract

The vegetative and reproductive phenological behavior of Jatropha mollissima (Pohl) Baill., Jatropha mutabilis (Pohl) Baill. and Jatropha ribifolia (Pohl) Baill. were characterized and compared in an area of hyperxerophilous shrub-arboreal caatinga in northeastern Brazil from July 2005 to June 2007. The correlation between the phenophases and the abiotic variables (temperature, relative air humidity, precipitation and photoperiod), the capacity for water storage and the patterns of spatial distribution of these species were also investigated. All species showed high capacities for water storage, continuous and irregular phenological behaviors with flowers, fruits, leaf fall, and leaf budding absence during the coldest and wettest months. Only flowering in J. ribifolia demonstrated significant correlation with precipitation. All species presented aggregated distribution of their populations, which was favored by the ballistic autochory. These results indicated that the high capacity of these species for storing water facilitates the occurrence of phenological events even in the absence of rainfall.