Adventitious rooting on the Brazilian red-cloak and sanchezia after application of indole-butyric and humic acids

摘要

Plant regulators, as well as bioactive fractions of the organic matter, can accelerate the development and increase the efficiency of adventitious rooting in ornamental plants. We evaluated rooting in the Brazilian red-cloak (Megaskepasma erythrochlamys) and sanchezia (Sanchezia nobilis) cuttings in response to application of indole-butyric acid (IBA) and humic acids (HA). Stem cuttings of both species treated with solutions of 0, 250, 500, 1000, 2000 mg/L of IBA and 0, 10, 20, 30, 40 mmol/L of C of HA were placed in 2.0 L plastic pots containing carbonized rice husk, kept in greenhouse. Survival of cuttings, number of leaves and shoot and root fresh and dry matter were evaluated 45 days after. Data were used to run an analysis of variance. We observed the average contrasts, calculated the regression equations and estimated the concentrations that provided the best efficiency in terms of root dry matter. For IBA, 185.4 and 66.8 mg/L were the concentrations that promoted the highest root dry matter accumulation in the Brazilian red-cloak and sanchezia, respectively, with increments of 140 and 22.5% in relation to the control. HA, at 33.6 mmol L-1 of C, increased shoot fresh and dry matter in the Brazilian red-cloak, but reduced root formation compared to the control. In sanchezia, HA at 19.5 mmol L-1 of C promoted increases of 35.9% in root dry matter in relation to the control. We concluded that IBA, in the abovementioned concentrations, increased adventitious rooting in cuttings of both the Brazilian red-cloak and sanchezia, while optimal doses of HA solutions are very likely to improve adventitious rooting in sanchezia, but not in the Brazilian red-cloak.