Shoot multiplication and some biochemical parameters of Stevia rebaudiana plants under the effect of biotic and abiotic elicitors in vitro

To study the shoot multiplication and to measure some biochemical parameters of Stevia under elicitors via in vitro condition, two experiments were conducted in a completely randomized design with three replications. Accordingly, in the first experiment, the effects of two cytokinins, Kin and BAP, at 0.5, 1, 1.5, 2, 2.5 and 3 mg/L concentrations to pick the optimal concentration as shoot multiplication protocol and then the effect of chitosan (CH), methyl jasmonate (MeJA) and yeast extract (YE) at 50, 100, 200 and 300 mg/L concentrations on plant growth and biochemical parameters of Stevia plant under in vitro culture was investigated as a second experiment. The primary experiment showed 2 mg/L BAP was the best regulator for shoot multiplication, therefore, supplemented with MS medium. The effect of various concentrations of elicitors showed a significant increase in shoot length and number. The highest amount of shoot length and number were observed in CH 200 mg/L, which showed a significant increase (70 and 95% respectively) compared to control plants. The effect of elicitors on biochemical parameters except for carbohydrates showed no effect compared to control. So that the water content and chlorophyll, showed more reduction with increasing doses of elicitors. The content of total carbohydrate was significantly increased by Chitosan 200, Methyl jasmonate 100 and Yeast extract 50 mg /L with relative to control. Overall, it was found that this research could be used as a proper protocol for mass production of Stevia rebaudiana as an economically valuable plant in tissue culture conditions.