Investigating the Effect of Drought Stress and Vermicompost Biofertilizer on Morphological and Biochemical Characteristics of Thymus vulgaris L.

This experiment was conducted to investigate the effect of drought stress and vermicompost biofertilizer on morphological and biochemical characteristics of Thymus vulgaris. It was done under water stress conditions in a greenhouse in Khorramabad Agricultural and Natural Resources Research Center. A factorial trial in a completely randomized design was carried out in three replications in a pot experiment. The factors including vermicompost fertilizer levels at 0, 30, 50, and 75% of pot volume and water stress including irrigation after depleting (85%) , 70% (mild stress), and 55% (severe stress) of moisture content of the field capacity were considered. The results showed that the morphological traits .including plant height, number of branches, plant fresh weight, plant dry weight and root length, were decreased with drought stress increase. Vermicompost consumption increased the morphological traits of the plant. Drought stress reduced the amount of Cymene in the air; but, at all levels of moisture stress, with increasing vermicompost consumption, the amount of Cymene was increased. The amount of secondary metabolites of Alfa-terpinen, Gamma-terpinen, thymol and carvacrol was decreased significantly with increasing drought stress. The amount of secondary metabolites and essential oil was increased significantly with increasing vermicompost consumption. The secondary metabolites were measured using GC MASS. According to the results of this study, severe stress in Thymus vulgaris L reduced growth and decreased shoot and morphological levels, which may be due to the plant's efforts to survive and achieve moisture. The secondary metabolites were decreased due to severe stress and improved with decreasing stress intensity due to increased shoots and increased metabolite production. Vermicompost biofertilizers increased the production of secondary metabolites by compensating for drought stress and gradually releasing the necessary plant elements.