The effect of different levels of soil moisture, zeolite and biofertilizers on physiological characteristics, yield and essential oil of dragonhead (Dracocephalum moldavica L.)

To study the effect of different levels of soil moisture, zeolite and biofertilizers on physiological characteristics, yield and essential oil of medicinal plant Dracocephalum moldavica L., this research was performed in 2010 at Tehran university research greenhouse. For this purpose, a factorial split-plot experiment in RCBD with 4 replications was used. In this study the main plots included different soil moisture levels (90%, 60% and 30 % FC) and subplots consisted of two levels of zeolite (zero, 8gr 4kg-1 soil) along with four levels of biofertilizers (without biofertilizer, nitroxin, biphosphorous, nitroxin+biphosphorous). Results showed that the highest amount of total, a and b chlorophylls, relative water content and yield of essential oil were obtained through %90 FC, but the highest amount of solution carbohydrates, proline and percentage of essential oil were obtained through %30 FC. The maximum amount of studied physiological traits as essential oil percentage and essential oil yield were obtained from application of nitroxin+biophosphorous. Interaction effects of soil moisture, zeolite and biofertilizers showed significant differences among different treatments on amount of a, b and total chlorophyll, relative water content, percentage and yield of essential oil. The maximum amount of oil yields were obtained from zeolite application and combination of nitroxin+biphosphorous and 60% FC and treatment of no consumption of zeolite and combination of nitroxin+biphosphorous with 90% FC. It could be concluded that moderate drought stress (60% FC) with application of zeolite and combination of nitroxin+biphosphorous is beneficial for Dragonhead essential oil yield.