Improved Micropropagation of Stevia (Stevia rebaudianaBertoni) Plant

Abstract

There is a great interest on the strategical plan in Egypt for the cultivation of a new crop used as source of natural sweeteners Stevia rebaudiana (Spanti) and (China-1) var. Stem nodal segments containing axillary buds were used as an explant and inoculated on Murashige and Skoog’s (MS) medium containing 3% (w/v) sucrose, 0.8% (w/v) agar supplemented with various concentrations of flurprimidol (flur.), paclobutrazol (PBZ) and thidiazuron (TDZ). In Spanti var. maximum number of branches (6.52) and (6.4) were obtained in MS medium supplemented with 0.12 mg/l flur. and 0.2 mg/l TDZ, respectively with an average of 56.4 and 36.67 leaves per plantlet, having an average shoot length of 6.40 and 6.52 cm, respectively. The best in vitro root induction (100%) was achieved on MS medium with 0.16 mg/l flur. with an average of 10.00 roots per plantlet and root length of 4.82 cm (Spanti var.). Furthermore, in China-1 var. (MS) medium supplemented with 0.16mg/l flur. induced the best morphological characteristics. The rooted plantlets from explant planted on (MS) medium supplemented with 0.16 mg/l flur. were successfully established in soil and grown to maturity at the survival rate of 100% in the greenhouse in (Spanti) and (China-1) var. As a result of anatomy, all studied growth regulators significantly enhanced the anatomical characters of stevia varieties leaf and stem.flur.at 0.16 mg\l surpassed, for instance, midvein and lamina thickness, length and width of leaf vascular bundle as well as stem diameter, xylem and phloem thickness. Our data revealed that the numbers of protein bands in most of treatments are bigger than which in the control.