Determination of Rebaudioside-a content of in vitro propagated stevia (Stevia rebaudiana Bertoni)

Stevia rebaudiana Bertoni is a perennial shrub which produces zero-calorie diterpeneglycosides in leaves. This study involves two main parts; seed germination and best nutrient combinations for in vitro propagation. In most of our experiments, number of leaves and nodes, shoot and root length, and steviolglycoside content were studied. The seeds of stevia were germinated in vitro under different light densities ranging from 0.8 to 5 klux. Of all the light densities tested, 5.0 klux was found to be the most effective for seed germination. Another experimental results with HPLC analysis showed that the control treatment produced nearly 10 times higher Reb-A than Fe-deficient treated plants. These results suggest that Fe affects growth and Reb A content in stevia plant. According to the results, highest Reb-A was found in stock 5 solution of Murashige and Skoog (St5) deficient medium (2.72%) with the lowest stevioside content (0.86 %) as compared to the other St5 treatments. This is the first study to observe the effects of different concentration of some selected microlements on in vitro culture of stevia plants.