Morpho-anatomical changes in leaves of Mentha x gracilis Sole (Lamiaceae) submitted to different levels of shade

Abstract

Mentha x gracilis Sole (Lamiaceae), known as gingermint, is a medicinal species of great importance, whose pharmacological properties are associated with the production of essential oil, with is rich in monoterpenes. This study aimed at evaluating the impact of different light regimes on a M. x gracilis clone. The plants were cultivated under shading (30% and 60%) and in full sunlight for 105 days. Subsequently, the leaf samples were submitted to morphometric analysis (leaf area, thickness, hardness, stomatal index and trichome density). The different conditions of light intensity promoted distinct changes in leaf morphology and anatomy. Plants cultivated in full sunlight were harder, thicker and presented a higher density of trichomes while plants grown under 30%-60% shade presented higher stomata density and leaf area.