influence of drought stress, biofertilizers and zeolite on morphological traits and essential oil constituents in dracocephalum moldavica l.

Background: essential oil content and composition in medicinal and aromatic plants is highly affected by both biotic and abiotic factors.objective: to investigate the effects of drought stress, zeolite and biofertilizers on morphological characteristics and essential oil constituents in dracocephalum moldavica l.methods: this experiment was conducted in the form of split factorial based on randomized complete block design with three replications in two years (2014 and 2015). the factorial experimental treatment was three levels of soil moisture (90%, 60% and 30%fc) applied to main plot, while application of zeolite (0 and 2 g per kg of soil) and biofertilizers (control, nitroxin, phosphate barvar2 and nitroxin times;phosphate barvar2) were applied to sub plots.results: application of zeolite had the highest effect on plant height, leaf area, dry matter and flowering top branches yield (ftby) in 90%fc and essential oil percentage and yield in 60%fc. similarly, combination of nitroxine+phosphate barvar2 caused maximum value of plant height, leaf area, dry matter and ftby in 90% fc and essential oil percentage and yield in 60%fc. the gcms analysis of the essential oil identified 14 compounds including ester and non ester combinations. the main compounds of ester combinations were geranyl acetate and neryl acetate and the main compounds of non ester combinations were neral, geraniol and geranial. the maximum percentage of ester and non ester combinations produced in 30%fc and 6090%fc, respectively.conclusion: application of zeolite accompanied by combination of nitroxine+phosphate barvar2 produced the highest value of examined traits in d. moldavica l.