Interactions Between Indolebutyric Acid, Uniconazol and Two Types of Growing Media in the Rooting of Stem Cuttings of Sapium glandulatum (Vell.) Pax. (Pau-de-leite)

Abstract

Pau-de-leite (Sapium glandulatum (Vell.) Pax., Euphorbiaceae) is a native tree of several Brazilian biomes, with great interest for rehabilitation of  degraded ecosystems due to its rusticity and intense seed dispersal by birds. However, its sexual  propagation is difficult because the majority of the  flowers are male and the percentage of germination of  the seeds is very low. Considering the propagation difficulty using seeds, during 2001 and 2002 a trial on  vegetative propagation by cuttings were done at  Embrapa Florestas (Colombo-PR), where stem cuttings 15 cm length and two half leaves left, collected during  the four seasons of the year, were tested. The stem  cuttings were treated with 0, 6000 and 12000 mg L-1 of only indolebutyric acid (IBA) or associated with 100 mg L-1 of uniconazol (UZ) in solution by 10 seconds. Once treated the cuttings were planted in polypropylene boxes with vermiculite and carbonized rind of rice growing media, remaining in greenhouse under  intermittent mist during 70 days. Data were analyzed using a completely randomized design with 12 treatments with four replications each, the  experimental  nit being 20 cuttings. The treatments  represent a factorial arrangement of the six doses  tested over the two growing media, totaling 960 cuttings for each season. The highest rooting value (11.3%)  occurred in the spring of 2001 with 6000 mg L-1 IBA + 100 mg L-1 UZ in carbonized rind of rice growing media. Dead stem cutting was greater than 88% in all seasons for all tested treatments.