Document Type : Research Paper


1 Department of Horticultural Sciences - Faculty of Agriculture - Bu-Ali Sina University - Hamedan - Iran

2 Department of Horticultural Sciences - College of Agriculture - Bu-Ali Sina University - Hamedan - Iran

3 همدان - خیابان مهدیه - 12 متری توحید - نبش کوچه شهید خادم - ساختمان مهتاب واحد 10- محمد سیاری - تلفن منزل 38398894


The phonological stage which abotic stress occurs is effective in determining the content of secondary metabolites in medicinal plants. In this research, the effects of drought stress imposing at different phenological stages on growth and some physiological and phytochemical responses of Nepeta crispa L were studied as a split plot design in Bu-Ali Sina University during 2019. Drought stress at three levels including mild, moderate and severe stress (with 80, 60 and 40% of field capacity, respectively) was applied at two phenological stages (seedling establishment stage with 6 true leaves and pre-flowering stages). The results of statistical analysis showed that drought stress had a significant effect on all evaluated growth traits and phytochemical parameters of the plant including proline content, relative water content (RWC) of leaves, total phenols, flavonoids, tannins, antioxidant activities and phenolic acids. Imposing drought stress at both phenological stages reduced plant growth and decreased chlorophyll content and RWC. However, production of phenolic compounds and phenolic acids (including rosmarinic, chlorogenic and caffeic acids) at high level and the accumulation of proline by imposing drought stress reduced the adverse effects of stress and increased the medicinal properties of the Nepeta crispa. Also, the effect of drought stress imposing at pre-flowering stage was greater than its application in the seedling establishment stage. According to the results, it is recommended to impose moderate drought stress at pre-flowering stage to increase biosynthesis of some phytochemical compounds in Nepeta crispa medicinal plants.