Evaluation of Growth Characteristics and Essential Oil Yield of Dragonhead Treated with γ-Aminobutyric acid and Ascophyllum nodosum Extract

In order to investigate the effect of gamma aminobutyric acid and Ascophyllum nodosum extract on some physiological, morphological and biochemical properties of medicinal vegetable Dragonhead (Dracocephalum moldavica L.), a factorial experiment based on randomized complete block design with nine treatments and three replications was performed in the greenhouse. Treatments included different concentrations of gamma aminobutyric acid at three levels (0, 200 and 400) μM and Ascophyllum nodosum at three levels (0, 1 and 2) % v/v. The results showed that the highest fresh and dry root and shoot weight, number of leaves and the lowest amount of malondialdehyde were obtained affected by GABA 400μM+Ascophyllum extract %1v/v. Also, the highest seed weight was observed in GABA 200μM+Ascophyllum extract %2v/v treatment. Interaction of GABA 200μM+Ascophyllum %1v/v extracts had the best results on chlorophyll content, carotenoids, stem diameter and vegetative yield. The highest yield of essential oil was assigned to the combined treatment of GABA 400μM+Ascophyllum %2v/v. finally, foliar application of GABA 200μM+Ascophyllum %1v/v is recommended to increase the vegetative yield of dragonhead.