DENSIDADE DE TRICOMAS GLANDULARES E PRODUÇÃO DE ÓLEO ESSENCIAL EM MENTHA ARVENSIS L., MENTHA X PIPERITA L. E MENTHA CF. AQUATICA L.

Abstract

The genus Mentha has economic importance as a source ofessential oil for food, cosmetic and pharmacy industries. Terpenes arethe main constituents of the essential oil of these species and theirbiosynthesis is located in leaf peltate trichome glands. The essential oilyield and composition of the species Mentha cf. aquatica L., Mentha xpiperita L. e Mentha arvensis L. was compared and the density of trichomeglands on leaf zones (abaxial proximal, abaxial middle, abaxial distal,adaxial proximal, adaxial middle and adaxial distal) determined. Theexperiment was carried out at Center of Experimental Station of Canguiri,UFPR, using plants propagated by stem cuttings. The trichome countingwas performed by optical microscopy on expanded leaves of the sixthinternode and the essential oil extraction by hydrodistillation during sixhours. The highest density of trichomes was observed on middle andproximal zones of Mentha arvensis and distal adaxial zone of Mentha xpiperita. Mentha cf. aquatica showed the highest density of trichome ondistal zone of abaxial face. Other factors beside trichome density as lossesby volatilization and catabolism seems to be more important ondetermining the essential oil accumulation as higher yield was observedin Mentha x piperita (32.09 µL.g-1 DW) and Mentha cf. aquatica (33.23µL.g-1 DW) than in Mentha arvensis (16.61 µL.g-1 DW). The constituentslinalool and linalyl acetate were predominants on M. aquatica and M. xpiperita, and α-terpineol on M. arvensis. The obtained results indicatethe possibility to use these genetic materials for linalool production bythe cosmetic and food industry.