The effect of drought stress on percentage and yield of essential oil and physiological characteristics of Deracocephalum moldavica L

In order to investigation effect of drought stress essential oil percent and yield and physiological characteristics of medicinal plant Deracocephalum moldavica L. under greenhouse. This research performed in 2004-2005 at research institute of forests and rangelands. Experiment was carried out in a split plot under randomize complete block design with four replications. Main factors were contains of three populations of Deracocephalum moldavica L. that collected from Tehran, Esfahan and Fars provinces. Subplots were contains three level of drought stress 100% Fc, 60% Fc and 40% Fc. The results showed that effect of different populations not significant. The results showed that effect of drought stress on essence yield, amount of solution carbohydrates, amount of a, b and total chlorophyll at two years were significant. So effect of drought stress on proline in second year was significant. The results analysis variation of two years showed that effect of year on essential oil percent and proline amount was significant (α=1%). Comparison mean of treatments showed that at first year highest of essence yield, solution carbohydrate and chlorophyll respectively related to 60%, 40% and 100% of field capacity treatments. At second year highest proline amount, solution carbohydrate and chlorophyll respectively related to 40%, 40% and 100% of field capacity treatments. Comparison mean treatments of plant populations and different levels of drought stress showed that at first year highest of essential oil percent related to Esfahan seed*60% humidity of field capacity. Highest chlorophyll relate to 100% humidity of field capacity in three ecotypes. At second year highest solution carbohydrate and chlorophyll respectively related to 40% and 100% of field capacity in three populations.