LIGNOANATOMICAL VARIATION IN SEEDLINGS OF Eucalyptus grandis (Hill ex Maiden) TREATED WITH GROWTH REGULATORS

Abstract

The aim of this study was to analyze the influence of growth regulators GA3 and BAP on lignification and consequently on the diameter of fibers in Eucalyptus grandis plants at age six months. Anatomical, biochemical and genetic studies after exogenous application of growth regulators during the development phase have been increasingly explored. Some of these studies have achieved progress regarding the interaction of plant hormones with the anatomy and the lignification process in plants. The application of growth regulators GA3 and BAP was done separately or combined in the following concentrations: GA3 (49.13 μM and 98.26 μM), BAP (111 μM and 222 μM), using seedlings of Eucalyptus grandis at age up to six months. Chemical and anatomical analyses were performed on the stem segment of plants subjected to treatment. To quantify lignin content by the Klason method, samples were subjected to removal of extractives and proteins. To measure fiber diameter, once dissociated, samples were analyzed by optical microscopy. The lignin content ranged between 23.37% and 29.64% and fiber diameter ranged between 13.33 μm and 20.39 μm. From results it was possible to visualize, with the G[1]C[1] treatment (49.13 μM of GA3 with 111μM of BAP) that lignin content dropped by 21.2% in relation to the control treatment, and that fiber diameter had the smallest increase in relation to other treatments.