The Effect of Potassium Concentrations on the Growth and Development of Stevia rebaudiana (Bertoni) and Production of Stevioside and Rebaudioside A.

Stevia rebaudiana (Bertoni) or popularly called as stevia is widely used as natural sweeteners for diabetic patients where it is either used as a substitute for sucrose in food and beverages or used together with sucrose. This is due to the presence of the sweet glycosides in the leaves that are hundreds times sweeter than sugar and have zero calories. The presence of sweet glycosides in S. rebaudiana (Bert.) leaves had cause a high demand for its function as sugar alternatives and sweetening agent in diabetic patient’s food and beverage. There were many researches done on this herb in increasing its yield such as growth regulator manipulation, light, water and temperature controlling in greenhouse and genetic modification. However, there is no study had been done on the macronutrient manipulation in S. rebaudiana (Bert.), especially potassium (K). Potassium ion (K + ) is the most abundant cellular cation and so is required in large amounts by most plants. The aim of this study was to examine the effect of K concentrations on the growth and development of S. rebaudiana (Bert.) and production of stevioside and rebaudioside A by using plant tissue culture technique. From this study, it was found that 4x K concentration produced the highest numbers of leaves (22.00±2.21), number of branches (2.96±0.48), number of nodes (9.40±0.85), number of shoots (1.80±0.14), highest shoot length (2.95±0.12cm), fresh biomass (0.07±0.01g) and dry biomass (0.006±0.001g). Meanwhile control group (0 K concentration) produced highest stevioside concentration (4.26±0.00mg/ml) and 2x K concentration produced the highest rebaudioside A yield (1293.06±0.58mg/ml). Different K concentrations in the plant tissue culture media had different effects on the growth and development of S. rebaudiana (Bert.) and production of stevioside and rebaudioside A. 4x K concentration is best for producing all of the studied physical characteristics while 0 K and 2x K concentration is best for stevioside and rebaudioside A production, respectively.