Study of effect of various calcium magnesium quotients on growth and some biochemical characteristics of Thymus vulgaris L.

Garden Thyme (Thymus vulgaris L.) is a medicinal plant belonging to the Lamiaceae. The natural distribution and effective substances of some thyme species have been related to the amounts of calcium and magnesium in the soil. Accordingly, in this study, the effects of different calcium to magnesium quotients (0.28, 0.8, 2, 3 (control) and 8), which contain 1 to 3.5, 2 to 2.5, 3 to 1.5, 1.5 to 0.5 and 4 to 0.5 mM calcium to magnesium concentrations, were investigated on the vegetative and physiological charactristics of garden thyme in a hydroponic culture in a completely randomized design. The results showed that the high amounts of calcium and magnesium in the nutrient solution resulted in a significant increase in the leaf chlorophyll, carotenoids and anthocyanins, soluble carbohydrates and total protein content and a decrease in the root and shoot potassium content of the plant compared to the control. On the other hand, at the 8 calcium to magnesium quotient in the nutrient solution, the root and shoot calcium concentrations increased and the magnesium concentration reduced. The highest amount of phenolic compounds of garden thyme was observed at the 8 quotient of calcium/magnesium treatment. The amount of phenolic compounds in the plant decreased compared to control by increasing available magnesium. The calcium to magnesium quotients applied in this study, especially the ratio of 0.8, resulted in a significant increase of average leaf area, fresh and dry weight of root and shoot compared to the control. In general, it can be stated that 8 and 0.8 calcium to magnesium quotients in nutrient solution were the best for the growth of the plant species, and an 8 quotient was the best for phenolic compounds production.