Densidade, anatomia e condutividade hidráulica de Machaerium opacum, Qualea grandiflora e Xylopia aromatica no cerrado mineiro

Abstract

Anatomical features of secondary xylem are important to understand strategies devised by species inserted in environments that have conditions that limit their survival and development. In order to measure basic density, xylem anatomical features and hydraulic conductivity, as well as to correlate them, we collected branches of Machaerium opacum, Qualea grandiflora and Xylopia aromatica present in the Cerrado of Minas Gerais. For each species five plants, three branches per plant were collected. Basic density was determined, anatomical features were measured, using histological slides and macerated material, and potential hydraulic conductivity for all species studied. Xylopia aromatica showed lower basic density and higher value for vessel tangential diameter, the latter being decisive to characterize X. aromatica as the most efficient species in water conduction. Machaerium opacum and Q. grandiflora, on the other hand, had the highest values of basic density, but Q. grandiflora, due to its higher frequency of narrower vessel diameter, proved that Q. grandiflora most invests in water security. Through correlations, we verified that the tangential diameter of the vessels is the anatomical characteristic that most influences the potential hydraulic conductivity, while in the basic density it is the thickness of the fiber wall. In addition, we found few support to confirm basic density as an indication of hydraulic efficiency.