Comparative study of the effect of drought stress on proline variations in Salvia leriifolia in soil and in vitro culture media

Salvia leriifolia (Lamiaceae) is an endemic plant of Khorasan and Semnan provincewith medicinal, antioxidant and nutritional properties. Drought stress affects on plantgrowth and development. To study changes in proline content of S.leriifolia affectedby drought and also identification of suitable environment for drought experimentstwo separate experimental (completely randomized design) was carried out in soil andin vitro medium. MS (Murashige and Skoog) medium was used for in vitro culture.Experiment was carried out in five different levels of water potential including 0, -2,-4, -6 and -8 bar with 4 replicates. Pressure plates were used in the soil experiment andPEG (Polyethylene glycol) was used in the in vitro medium. Proline in the leaves wasmeasured after the plants reached four leaf stage. The results showed that with increasing drought stress, proline accumulation in leaves was increased. This increase in the soil experiment was more than the in vitro one. It can be concluded that proline accumulation is a good measure plant responses to drought stress. Results of experimentsconducted in in vitro are more accurate because it is easier to control the environmentalconditions. It is also of less experimental cost and more space saving criteria.