Resumo. The present work tried to verify the effects of application of different concentration of indolebutyric acid (IBA) in talc in solution, in the rooting of cutting of Tibouchina sellowiana (Cham.) Cogn. collected in the four seasons, as well as its anatomical and biochemical variation. The semiharwood cuttings were treated with 0, 1500 and 3000 mg L-¹ indolebutyric acid (IBA), in powder and alchoolic solutions. After 65 days in a greenhouse, rooting percentage, length and number of roots, cutting with callus percentage and survival, were evaluated. The use of the IBA was efficient in the induction radicial, being indifferent the form in which it was applied. The most promising stations in the formation of the system radicial were the spring (78,75%) with 3000 mg L-¹ or mg kg-¹ IBA and the summer (63,12 %) with 1500 mg L-¹ or mg kg-¹ IBA. (82,50%) with 3000 mg kg-¹ IBA. Considering the cutting in the base of the stakes, in the moment of the cutting, no possible anatomical barrier or structural difference were detected so that it should promoted variations in the answers of the rooting uring the four seasons. Biochemical analyses done from the cuttings collected in the four seasons revealed that the largest concentrations of total sugars were obtained in the winter (83,21 mg g-¹) and in the autumn (72,79 mg g-¹). The same stations also presented the largest protein concentrations (4,69 and 3,95 mg g-¹ respectively).