Caracterização anatômica e química do sistema vascular secundário do caule do cafeeiro (Coffea arabica L.) recepado e em diferentes níveis de adubação

Abstract

Coffea arabica L. (Rubiaceae) is a very important species for the production of coffee in Brazil. However, the use of highly productive cultivars, whose nutritional requirements are high, makes the cultivation of the species sometimes very expensive. One way to optimize the use of fertilizers is to know which limits are supported by C. arabica at a structural (anatomical) level that do not compromise its productivity. In addition, seeking alternatives for prunning residues could increase the income of producers and ensure a sustainable destination for underutilized biomass. The objective of this work, in this way, is to characterize and compare the anatomy and chemical composition of the secondary vascular system of the stem of Coffea arabica cv. topázio, submitted to different fertilization levels, aiming to analyze how the possible differentiations found on secondary xylem, besides to verify the use of substances from cultive residues. For this, samples of C. arabica cv. Topázio MG 1190 were collected in the experimental area of the coffee sector from Universidade Federal de Lavras (UFLA), from one experiment implemented in the year of 2010, which undergone low-pruning in the year of 2015. The experiment received a fertilizing variation in 10, 40, 70, 100, 130 and 160%, according to the nutritional recommendation indicated for C. arabica. Orthotropic and plagiotropic stem samples were characterized as anatomy and chemistry (structural and non-structural) of secondary vascular system of the stem, following the usual methodology, adapted to the species. Anatomical differences were observed between the treatments and stem parts and in xylem functionality in plagiotropic stem. Anatomical differences in xylem probably occurred to answer to functionality, showing the plasticity of the tissue on the specie. Differentiated amounts of structural and non-structural chemical components were also found in pruning residual orthotropic stem, in the different treatments. The results revealed not only the plasticity of the coffee stem when submitted to differentiated fertilization, but also pointed out its potential in the reuse of chemical compounds when prunning is conducted.