Propagação, crescimento vegetativo e composição química do óleo essencial de Lippia origanoides Kunth

Abstract

Lippia origanoides Kunth species is a perennial shrub found in some Brazilian regions and used for medicinal purposes. Its essential oil has been shown to be effective in controlling fungi and bacteria that cause disease in humans, animals and plants. The aim of this study was to evaluate the propagation, vegetative growth and essential oil chemical composition L. origanoides Kunth. The experimental design was completely randomized (DIC), with four concentrations of AIB: zero, 250, 500 and 1000 mg L-1 and two substrates: Commercial and sand, distributed in two experiments: with cuttings containing a pair of leaves and the other with two pairs leaves, six replicates of four stakes in plots, totaling 384 cuttings planted in plastic cups with a capacity of 0,2 dm-3. 90 days was rated the absolute growth, the number of shoots and leaves, leaf area, rooting percentage, root length, fresh and dry weight of shoots and roots and total dry mass. For vegetative growth was used DIC with eight treatments and 10 repetitions, as described below: (T1) = 40 kg N ha-1; (T2) = 60 kg N ha-1; (T3) = 120 kg N ha-1, equivalent to 89, 133 and 267 kg ha-1 of urea respectively; (T4) = 60 kg ha-1 of N, P2O5 and K2O, equivalent to 133, 353 and 100 kg ha-1 of urea, superphosphate and potassium chloride, respectively; (T5) = 3,1 t ha-1 of manure (EB) (T6) = 4,6 t ha-1 and EB (T7) = 9,2 t ha-1 of EB, equivalent to 40, 60 and 120 kg ha-1 N, respectively; and (T8) = Witness - without chemical fertilizers and without organic. We evaluated the absolute growth, stem diameter and crown every 30 days and leaf area (AF), dry weight of leaf (MSF), dry mass of the stem (MSC), root dry mass (MSR), mass dry total (MST), root length (CR), essential oil content (OE), macronutrients and foliar micronutrients to 150 days. The analysis and identification of chemical compounds in the essential oil were made from samples taken from each treatment equipment gas chromatography coupled to mass spectrometry. It was concluded that for the stakes with a pair of leaves, the concentration of 250 mg L-1 in the sand substrate favors 100% rooting, increases the number of shoots and leaves, dry weight of shoots and roots and total dry matter. The concentration of 500 mg L-1 increases the leaf area and the concentration of 1000 mg L-1 provides greater height of shoots on substrate sand. I t was also concluded that sand is the best substrate for rooting of cuttings and seedling L. origanoides Kunth species when compared to the commercial substrate. The application of AIB does not influence the rooting of cuttings with two pairs of leaves in the commercial substrate and sand. The concentration of 250 mg L-1 of AIB promotes the total height of the shoots and leaf area of the cuttings with two pairs of leaves in the sand substrate. In the commercial substrate, higher average height, number of shoots, dry mass of shoots, roots and total dry mass was obtained in the concentration of 1000 mg L-1 IBA, but below the sand substrate. It is possible to produce seedlings of L. origanoides Kunth from cuttings with two pairs of leaves in sand substrate. The fertilization with manure and NPK fertilization favored growth, stem diameter, crown diameter, leaf area and total dry mass. The fertilization with 60 kg N ha-1, equivalent to 4.6 t ha-1 of manure, showed the highest absolute growth of L. origanoides Kunth to 150 days of cultivation. Increased production of essential oil and P content and accumulation of Zn in the leaves was obtained at a dose of 120 kg ha-1 N, equivalent to 9.2 t ha-1 of manure. The NPK fertilization favored manganese accumulation in the leaves. Less accumulation of calcium and potassium levels was observed in treatments fertilized only with nitrogen. 58 chemical compounds were identified in the essential oil of L. origanoides Kunth between monoterpenes, sesquiterpenes and diterpene. The major compounds of the essential oil were carvacrol, α-humulene, geranyl acetate, bicyclo [3.1.0] hexane-6-methanol, 2-hydroxy-1,4,4-trimethyl-, humulene oxide, thymol, farnesyl acetate 3, eucalyptol and p-cymene. Smaller doses of chemical and organic fertilizer or without fertilizer showed the highest concentrations of carvacrol and α-humuleno, while the fertilization with NPK favored the concentration of geraniol geranyl acetate.