The Effect of Spraying Salicylic Acid and Beta-Aminobutyric Acid on Physiological and Biochemical Characteristics and Yield of Dracocephalum moldavica (L.)

In order to investigate the effects of foliar spraying of salicylic acid and beta-aminobutyric acid on yield, physiological and biochemical characteristics of Dracocephalum moldavica (L.), during cropping year of 2017-2018, in a experiment based on a randomized complete block design with 4 replications was carried out in Kerman. Foliar spraying was done one month before harvesting with three concentrations (0, 0.5 and 1 mM). Plant height, stem diameter, number of leaves, fresh matter yield, dry matter yield, number of lateral branches, yield of total extract and essential oil were measured. Identification of essential oil components was done by using a gas chromatography (GC) which was connected to a mass spectrometer (GC/MS) by comparing the inhibition indices and mass spectrometry study. According to the results, the effect of both elicitors of salicylic acid and beta aminobutyric acid on plant height, number of leaves, fresh matter yield and dry matter yield were significant at 1% level of probability; But, there was no significant difference in stem diameter and number of lateral branches. The interaction effect of both elicitors on plant height and dry matter yield was significant at 5% and 1% probability levels, respectively. While there was no significant difference on other traits under study. Also, the use of both elicitors increased the total extract and essential oil yields. The highest percentage of main compounds in essential oil was affected under the influence of the amount of 1 mM salicylic acid in absence of beta aminobutyric acid, including 36.8% geranyl acetate, 20.5% geraniol, 19.7% geranial, 14.9% neral and neral acetate 2.9%. In general, the use of salicylic acid was found and beta-aminobutyric acid to increase Dracocephalum moldavica (L.) yield.