Effects of three types of fertilizers on essential oil, photosynthetic pigments, and osmoregulators in chamomile under drought stress

In order to study the effects of drought stress and three types of fertilizers on photosynthetic pigments, osmotic regulators and essential oil of chamomile, a split plot field experiment based on CRD design was conducted with three replications in 2008 at university of Zabol. Drought treatments included 90% FC (control W1), 70% FC (W2) and 50% FC (W3) as main plots and fertilizer treatments included non fertilizer (F1), chemical fertilizer (F2), manure (F3) and compost (F4) as sub plots. In this study, drought stress led to increased essential oil percentage, whereas the greatest essential oil percentage and yield obtained when 70% FC was applied. Increasing drought stress level enhanced the amount of carotenoid, proline, and carbohydrate in leaves, while decreased the amount of Ch a and Ch b. Among fertilizers, chemical fertilizer had the highest effect on essential oil content. Results showed that chamomile accumulates proline and carbohydrates to tolerate the drought stress. The maximum essential oil content could be achieved applying mild water stress levels. Moreover, using manure fertilizer under high level of drought stress was more effective.