Effect of Serendipita indica inoculation and foliar application of potassium on growth and morphophysiological traits of Dracocephalum kotschyi under drought stress

Abiotic-stress tolerance and plant growth enhancement can be evoked in crops by the exploitation of beneficial microorganisms and optimal provision of plant nutrients. The effect of inoculation with Serendipita indica and foliar application of potassium on growth and morphophysiological characteristics of Dracocephalum kotschyi plant under drought stress was the goal of the present experiment. The study was conducted in a completely randomized design with two levels of fungus inoculation (non-inoculated and inoculated with S. indica), three levels of potassium application (0, 1 and 3% K) and two levels of drought stress (Field capacity (F.C.) and 50% F.C.) with three replications. The results showed that drought stress decreases the biomass, relative water content, chlorophyll and potassium. While inoculation with S. indica and potassium application increased traits such as shoot and root biomass, relative water content, chlorophyll, potassium and antioxidant enzymes and consequently reduced the harmful effects of drought stress. Drought stress caused membrane instability by increasing electrolyte leakage and malondialdehyde, while inoculation with fungus and potassium treatment reduced lipid peroxidation and electrolyte leakage. Due to the importance of D. kotschyi and the effect of biomass increase on the amount of its medicinal substance, inoculating with S. indica and foliar application of potassium can be a suitable method to enhance the growth and drought stress tolerance of D. kotschyi.