Drought effects on growth, water status, proline content and antioxidant system in three Salvia nemorosa L. cultivars

Plant growth and yield are influenced by various environmental stresses, especially drought. An experiment was done to study the comparative effects of water stress on growth, physiology and antioxidant systems in three Salvia nemorosa L. cultivars (Isfahan', Violet Queen' and Rose Queen'). The cultivars were treated as control or water stress by stopping irrigation for 10days. The results showed that the highest number of leaves per plant, leaf area, dry weight of root and shoot and total biomass were obtained from native cultivar Isfahan' under water shortage. Relative water content, chlorophyll a, b and total chlorophyll reduced in all studied cultivars under drought; but the rate of reduction was the lowest in Isfahan'. Drought stress increased total soluble sugar in the root and leaf tissues in all cultivars and the highest values were obtained from native cultivar Isfahan'. Drought stress also increased proline content, total phenols and flavonoids in all tested cultivars; but the rate of increase in Isfahan' was higher than the other cultivars. The activities of catalase and peroxidase enzymes enhanced in all cultivars under drought stress conditions; however, their activities were higher in Isfahan' than the other cultivars. Among the cultivars studied, it was found that Isfahan' was more tolerant which was revealed by physiological and biochemical characteristics.