| Abstract [eng] |
Master thesis of Viktorija Popkovaitė „Comparison of Leaf Epidermis Anatomical Structures and Essential Oil Composition in Mentha Species Growing Wild in Lithuania“. Supervisor: dr. Kristina Ložienė; Vilnius University, Faculty of Medicine, Institute of Biomedicinal Sciences, Pharmacy and Pharmacology Center, Vilnius. Key words: Mentha arvensis; Mentha longifolia; Mentha aquatica; vegetative phases; essential oil; glandular trichomes. The aim of the study: To determine the differences in the anatomical structures of the leaves epidermis and the essential oil composition between Mentha species, growing wild in Lithuania, and different vegetative phases. Main tasks: To compare the quantitative composition of essential oils accumulated in field mint (Mentha arvensis), water mint (Mentha aquatica) and horse mint (Mentha longifolia), plants in different vegetative phases; to compare the qualitative composition of the essential oil in these mints in different vegetative phases; to compare the density and diameter of glandular trichomes in the epidermis of leaves of these mints in different vegetative phases. Object: 3 species of the genus Mentha naturally grow in Lithuania. Field mint is a perennial herb that is widespread throughout the country and grows in clay-rich soil. Perennial herbaceous horse mint is not common in Lithuania and found at the edges of swamps usually. Water mint is a perennial herbaceous plant that is widespread in Lithuania and grows at the coasts of rivers. All mints were collected during different vegetative phases: before flowering, during flowering, and after flowering. Forest and aquatic mints were cultivated at the Field Experimental Station of the Nature Research Center (Mažieji Gulbinai, Vilnius), as well as aquatic mint was collected from natural habitat on the right shore of the Žeimena river (Pabradė, Švenčionys district). Methods: In this study we used extraction of essential oils from plant material by hydrodistillation method; determination of the chemical composition of essential oils by the gas chromatography-mass spectrometry method; analysis of the anatomical structure of leaf epidermal glands. Results and conclusions: regardless of the vegetation phase, the highest amount of essential oil was found in water mint – 1,42±0,09%, and the lowest - in field mint (0,71±0,43%) plants; none of the tested mint essential oils differed between vegetation phases; in both field and water mint, the density of essential oil glands in the upper epidermis of the leaf (3,1±0,3 and 1,8±0,5 glands/mm2) statistically reliably (p<0,05) differed from the density in the lower epidermis (respectively 1,1±0,5 and 3,7±1,4 glands/mm2); ); in field mint, the density of glands before flowering and during flowering reliably differed from the density after flowering, in water mint, the density of essential oil glands increased consistently during the investigated vegetation phases; in all studied mints, the diameter of the essential oil glands increased consistently during the studied vegetation phases; a total of 199 different compounds were identified in the studied mint species, Z-β-ocimene (12,31±4,67 %) and decyl acetate (12,61±3,61 %) in the essential oil of field mint contained the largest part, carvone (39,72±14,88 %) of horse mint, and menthofuran (44,09±3,18%) in water mint. |
