Authors : Sadrollah Ramezani , Fatemeh Ramezani , Farzad Rasouli , Mehdi Ghasemi and Mohammad H. Fotokian
Abstract: The yield of the essential oil from the leaves of Eucalypt (Eucalyptus nicholii), Rosemary (Rosmarinus officinalis L.), White Cedar (Thuja occidentalis L.) and Lawson Cypress (Chamaecyparis lawsoniana) shows seasonal and diurnal variation. In order to, aerial shoots of those plants harvested in three times (6, 12 and 18) and then dried in shade condition as natural method. The essential oils obtained by hydrodistillation way. This research carried out with 5 replications in random completely design and amount of essential oils measured in any species base on dry mater and data analysis performed with LSD test. Amount of essential oils in both of Lawson Cypress and White Cedar species at 7 h were high in compared with other treatments in 1% level and non significant difference between 12 and 18 times in Lawson Cypress. The results indicated that maximum of essential oil in Eucalypt and Rosemary obtained in 12 and 18 times, respectively that have significant differences with other times in 1% level. According these results we conclude that for obtaining of more yields of essential oil and other volatile compounds, harvesting of matter plants must be accomplished at special time in one day.
Sadrollah Ramezani , Fatemeh Ramezani , Farzad Rasouli , Mehdi Ghasemi and Mohammad H. Fotokian , 2009. Diurnal Variation of the Essential Oil of Four Medicinal Plants Species in Central Region of Iran. Research Journal of Biological Sciences, 4: 103-106.