EThe effect of proline and 24-epibrassinolide on growth indices and biochemical characteristics of the summer savory (Satureja hortensis L.)

Proline is a common compatible osmolyte and, by osmotic regulation and protecting membranes, proteins and enzymes, protects plants towards destructive effects of osmotic stresses. Brassinosteroids are a new group of plant growth regulators and stimulate their growth. The effects of foliar spraying of proline and 24-epibrassinolide on growth indices and biochemical characteristics of summer savory (Satureja hortensis L.) were investigated in this study in greenhouse conditions. Foliar treatments including control (no spraying), proline (20 mM) and 24-epibrassinolide (1 μM) were performed in both vegetative and reproductive stages. According to the results, foliar proline led to increasing plant prolin content to 394.4%, chlorophyll index to 4.8%, total phenol to 9.8%, flavonoids to 18%, yield of essential oil to 15.8%, fresh weight of aerial parts to 8%, dry weight of aerial parts to 7.8%, fresh weight of leaf and flower to 6.8%, dry weight of leaf and flower to 8% and stem diameter to 7.4% compared to the control. In addition, 24-epibrassinolide spraying caused a significant increase in phenolic compounds (32.15%) and internode length (8.3%) of the plant in coparision to control.