Growth, production and chemical composition of the essential oil in hortelã-do-campo (Hyptis marrubioides Epl.) in function of the irradition level

Abstract

In the present work, the level of irradiation of 20, 60 and 100% of natural light on the growth, content and composition of the essnetial oil of “hortelã do campo” (Hyptis marrubioides) was evaluated. The experiment was conducted in the completely randomized design with twenty-five replicates per treatment. After 132 days of cultivation, plant growth and the content and compositoin of the essntial oil were investigated. At 100% of irradiation, the plants presented less height as compared with the shaded treatments. The ratio branch/leaf was higher at the level of irradiation of 20%. It was found that in the full sunshine, the plants showed lower height as compared with the shaded treatments. The leaf/ branch ratio was higher at the lowest level of irradition of 20%. The number of branches and the plant mass accumulation were greatest at the level of irradition of 100%. The content of essential oil was not influenced by the levels of irradiation, but the yield was greater when grown at the level of 100% of irradiation. The chemical composition of the essential oil of Hyptis marrubioides did not present any alterations with the different levels of irradiation, except for iso-3-tujanol and ?-cadineno, which presented highest concentrations in plants grown, respectively at 100 and 60% of irradiation. The major component of teh essential oil of H. marrubioides, independent of the levels of irradiation was cistujona oxygenated monoterpene (37.78%), followed by sequiterpenes hiydrocarbonetes (E)-cariofileno (14.93%), ?-copaeno (11.03%) and ?-muuroleno (9.60%).