The impact of the environmental factors on yield and chemical compositions of essential oil of water mint, Mentha aquatica L. from different habitats of Mazandaran province

Water mint grows widely in Northern provinces of Iran. Plant shoots and soil samples have been collected before flowering phase from four different sites, east to the west of the province including Sari, Babol, Nowshahr and Tonekabon in the spring season 2013 in three replications. Essential oil extraction was carried out by hydro distillation method with Clevenger apparatus and essential oil yield has been calculated in different localities. Isolation and identification of the essential oil components have been carried out with Gass Cromatography (GC) and GC/MS. Soil features including elements amount, acidity (pH) and electrical conductivity (EC) have been measured. Data analysis has been carried out with SAS software ver. 9.1. The results indicated that the essential oil yield based on dry plant weight was between 0.254% in Sari (east of the province) to 0.474% in Nowshahr (west of the province). The number of essential oil components showed a reverse trend in which the oil of Nowshahr consisted of the least components (26 components) and the oil of the Sari composed of the most (34 components). The most characteristic constituents of the oils were menthofuran, trans-caryophyllene, Eucalyptol, Germacrene- D and viridiflorol. The results of the soil experiments showed that decreasing of the soil pH and EC, increasing in N, P and soil organic and nutrient elements and more precipitation in the west of the province resulted in more oil yield but increasing of the soil pH and EC in the east leads to more components of the oil.