Quality of light and indolbutyric acid in vitro rooting of lavender

Abstract

Lavender, an aromatic and medicinal plant, used in the extraction of essential oil, as an ornamental and meliferous plant, can be successfully propagated as long as the light, the nutrient medium and the growth regulators are adequate. The aim of the study was to evaluate the effect of different concentrations of indolebutyric acid (IBA) associated to distinct light spectra, on the in vitro rooting of Lavandula angustifolia. The experiment consisted in the combination of two concentrations of indolebutyric acid in the growth medium (0 and 0.1 mg L-1) and two light spectra, using cellulose acetate filters (blue and red), besides the control (without filter), totaling six treatments with four repetitions. For each repetition five explants were used. After 30 days, the variables evaluated were: survival percentage, number of buds and leaves, shoot length, number of roots, length of the longest root, shoot fresh and dry matter weight. There was a significant interaction among the indolebutyric acid concentrations and the light filters for the variables number of buds, leaves and roots and shoot length. Except for leaf number, promising results were obtained when the explants were held under red filters and with a concentration of 0 mg L-1 of indolebutyric acid in the growth medium. From these results, it can be concluded that the best in vitro rooting of Lavandula angustifolia is obtained when there is no indolebutyric acid in the growth medium associated with the use of the red filter.