Vegetative propagation of mature dragon trees through epicormic shoots

Abstract

Epicormic shoots were induced in stumps and detached branches of adult Paulownia fortunei var. mikado plants to evaluate rooting potential. Stem cuttings obtained from shoots of stump were prepared with 12 cm in length and two leaves reduced to 78.5 cm² (10 cm diameter). Cuttings from shoots of branches were prepared with 8-10 cm in length, and two leaves reduced to 50 % of the original size. Anatomical analysis was performed to evaluate possible barriers to rhizogenesis. After disinfestation, indolebutyric acid (IBA) was applied (0, 500, 1,000, 1,500 and 2,000 mg L^-1). Installation was made in plastic pots with a volume of 170 cm³ and 53 cm³, respectively for each type of cuttings, with fine vermiculite and carbonized rice hulls (1:1 v/v) as substrate. After 60 days in a greenhouse, cuttings from epicormic shoots of branches presented rooting (58.12 %) and the average length of the three longest roots/ cutting (4.76 cm) was higher than in cuttings from stumps. The highest number of roots/cutting (7.66) and percentage of cuttings with callus (27.50) was observed in cuttings from stumps. There were no anatomical barriers observed harming the roots formation in the two types of cuttings. The use of indolebutyric acid is not required to induce rooting.