Níveis de sombreamento e tipos de malha no crescimento e produção de óleo essencial de hortelã-pimenta

Abstract

The objective was to evaluate plant growth, content, yield and chemical composition of essential oil of peppermint (Mentha piperita) grown under different nets and intensities of light. The plants were grown under the black net and aluminized net with different shading levels (0, 30, 50 and 70%). The harvest was done 4 months after plating. Foliar area, foliar weight ratio and essential oil content were not statistically different. The dry biomass of leaves, shoots, roots, total, ratio of foliar area and specific foliar area of plants cultivated under each net showed distinct responses in different shading levels. The peppermint plant growth was 12.5% lower in black net (32.6 g plant-1); more shading resulted in less biomass production in the aluminized and black nets (34.2 and 17.7 g plant-1, respectively). The essential oil yield was 1.26 mL plant-1 for black net and 1.34 mL plant-1 for aluminized net. The growth and essential oil yield were higher under full sunlight than under nets of distinct shading levels. The peppermint replied distinctly to nets and their shading levels for the production of majority monoterpenes thus suggesting its growth in full sunlight.