The structure of the glandular trichomes and essential oil of the aerial parts of Marrubium cuneatum Russell were studied. Most secretory tissues are located in glandular trichomes. The essential oil isolated by steam distillation were analysed by GC-MS. Among 25 compounds identified, representing about 89% of the oil, the major components were bicyclogermacrene (37.9%) and germacrene D (24.1% Isolation of the Essential Oil and Preparing SlidesThe essential oil was obtained by water steam distillation of air-dried aerial parts (250 g) in an all-glass apparatus. The sample oil, which was light yellow in colour, was dried over anhydrous sodium sulphate and stored under nitrogen in a sealed vial until required. Fresh stems and leaves were placed in a formalin-acetic acid-ethyl alcohol mixture and slides were prepared by hand-cutting and stained in a alum carmine-methyl green combination (all of the chemicals used were from Merck). They were photographed at standard magnification using an Olympus automatic camera. Gas Chromatography-Mass SpectrometryGC-MS analysis was carried out on a Varian 3400 GC-MS system equipped with a DB-I fused silica column (60 m × 0.25 mm, film thickness 0.25 µm) and interfaced with a Varian ion trap detector. Oven temperature, 50-270°C at a rate of 4°C/min; injector and transfer line temperature, 280°C and 290°C; carrier gas, helium with a linear velocity of 31.5 cm/s; split ratio, 1:60; ionization energy, 70 eV; scan time, 1 s; mass range, 40-400 amu.

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Summary The focus of this study is based on the examination of the germination traits and the development of thermal models of the medicinal plant Salvia leriifolia Benth. A laboratory experiment was carried out at constant temperatures ranging from 0 to 35°C, at 5°C intervals in a completely randomized design with eight replications. To describe the germination rate response to temperature, three regression models, namely Intersected-Lines (ISL), Quadratic Polynomial (QPN) and Five-Parameters Beta (FPB) were used. The highest Germination Percentage (GP) (92.8%) occurred in 15°C, but GP in the range of 10-25°C was not significant (p≤0.05). The germination process stopped at 0°C and at above 30°C. The results indicated that the highest Germination Rate (GR), the lowest Mean Germination Time (MGT) and also times to 50% germination (D50) were obtained at 20°C. Seeds did not reach to their 50% germination level in temperatures higher than 25°C. The FPB model had the best realistic estimation for cardinal temperatures. Based on models estimation, Base (Tb), Optimum (To) and Ceiling (Tc) temperatures were in the ranges of (1-1.9°C), (18.1-20.8°C) and (34.5-38.7°C), respectively.

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