INFLUÊNCIA DA CONCENTRAÇÃO E TEMPO DE EXPOSIÇÃO AO AIB NA RIZOGÊNISE DO Eucalyptus urograndis

The production via cutting, is one of the most important methods in the multiplication of forest species. The difficulty of rooting some species involves the participation of both factors related to the first plant in the environment, and is one of the most serious problems in the production of seedlings. The plant hormones stand out in the aid of the growth and development of the plant, and among the several classes, the auxins play important roles in the vegetative cycle, besides being closely related to the rooting. In this context, the objective of this work was to evaluate the percentage of rooting and root quality of E. urograndis I-144 clones that were exposed to concentrations and exposure times of IBA. The percentage of rooting, stem diameter, stem size, number of viable buds, root size, number of roots, and weight of fresh and dry matter were evaluated. The experimental design was completely randomized in a 2x5 factorial arrangement, with two concentrations of indole butyric acid (AIB) (500 and 1500 ppm) and five immersion times (1, 10, 30, 60 and 600 seconds) plus a control. The bases of the cuttings were either emerged or not (control) in IBA solution, and stacked in plastic tubes. With the results obtained in the study it can be stated that it is feasible to use IBA to increase the number of rooted cuttings in Eucalyptus urograndis. For best use of the AIB, it is recommended to use the 500 ppm solution within 10 seconds of exposure.