Evaluation of salinity adjusted by using humic acid and ascorbic acid in medicinal plant of moldavian balm (Dracocephalum moldavica L.)

In order to evaluate adjusting salinity by using humic acid and ascorbic acid in Moldavian balm, factorial experiment in a completely randomized design with three replications was conducted. Experimental treatments included salinity at four levels (0, 50, 100 and 150 mM), humic acid and ascorbic acid in three levels (0, 100 and 200 mg/l). Growth characteristics of plant such as subshrub length, inflorence length and root traits showed a significant decrease compared to control by increasing salinity stress and application of humic acid and ascorbic acid at both levels (mainly levels of 200 mg/l) have been improved these characteristics in comparison with control plants. Relative water content also decreased by salinity stress and the application of 100 and 200 mg/l of humic acid and ascorbic acid (to some extent) could compensation this damage. Also Electrical conductivity increased significantly under salinity stress and the usages of humic acid improve this trait. Antioxidant activity and total phenol decreased in 50 mM stress and by increasing salinity levels to 100 and 150 mM increased them. Prolin in different stress levels (50, 100 and 150 mM) was more than control (no salinity) and application of humic acid and high levels of ascorbic acid (200 mg/l) was reduced proline. This result could indicate moderating effect of the mitigation on physiological processes and growth characteristics of Moldavian balm plant under salinity stress, especially in high levels of their usage (200 mg/l).