Effect of seasonal variation on essential oil yield, and morpho-physiological properties of Achillea filipendulina Lam.

Achillea filipendulina is one of the most important species of the family Asteraceae and, it considered as one of the most valuable medicinal and ornamental plants. Environmental factors affected on quality and quantity of the essential oil of medicinal and aromatic plants. So, selecting of appropriate season for harvesting can lead to increase quality and quantity yield. The aims of the present study were to assess the effect of seasonal variation on essential oil yield and some morphophysiological traits of A. filipendulina. In this research, split plot experiment based on complete block design was conducted in three replicates. The aerial parts were harvested and the essential oil extracted by Clevenger approach in different seasons. Afc genotype showed the lowest amount concerning the plant height, leaf length and leaf width in winter, while Af21 had the highest height and leaf width in summer. The essential oil yield varied between 0.01 to 0.84% in all seasons. The highest and the lowest essential oil yield belonged to Afc in summer and Af21 in winter, respectively. The lowest and the highest hydrogen peroxide accumulation were in Af21 in spring and Afc in summer, respectively. Furthermore, malonede-aldehide (MDA) accumulation varied from 0.3 to 3.37 ng/fw. Afc in spring and Af21 in summer showed the lowest and the highest MDA, respectively. According to the results of present study, in order to increase dry matter and essential oil yield of Achillea filipendulina, harvesting for essential oil extraction is suggested in early summer.