ROOTING CUTTINGS FROM EPICORMIC SHOOTS OF Paulownia fortunei var. mikado ADULT TREES

Paulownia fortunei is a Chinese native species characterized by rapid growth and low wood density, associated with a natural resistance against xylophagous agents. Based on its low germination combined with the advantages of vegetative propagation, this work aimed to evaluate the effect of the rooting and root vigor of cuttings from epicormic shoots of mature trees coppiced near the base, collected in different seasons and under different concentrations of indolebutyric acid (IBA), as well as to check for possible anatomical and histochemical barriers to adventitious root emission. In fall/2011, spring/2011 and summer/2012 semihardwood cuttings were prepared with 10-12 cm and two leaves reduced to an area of about 78.5 cm(2) (10 cm diameter). Cutting bases were dipped in IBA at concentrations of 0, 500, 1000, 1500 and 2000 mg L-1. Cuttings were planted in 110 cm(3) plastic tubes, filled with fine vermiculite and rice hulls (1: 1 v/v), in a greenhouse. After 60 days, the percentage of rooting, number and length of roots/cutting, percentage of cuttings with callus and mortality were evaluated. Cuttings collected from stumps coppiced in summer presented the best results for rooting (47.5%), for mean length of the three longest roots/cuttings (5.65 cm) and percentage of cuttings with callus (51.25%). The use of IBA is necessary for root induction in cuttings of epicormic shoots from stumps of Paulownia fortunei var. mikado being recommended the concentration of 2000 mg L-1. There were no anatomical and histochemical barriers to the emission of new roots.