Effects of kinetin on the morpho-physiological and biochemical characteristics of stevia ( Stevia rebaudiana )

Khandaker, M. M., Liyana, N., Majrashi, A., Dalorima, T., Alias, N. & Mat, N. (2018). Effects of kinetin on the morpho-physiological and biochemical characteristic of stevia (Stevia rebaudiana). Bulgarian Journal of Agricultural Science, 24(4), 638–647 Stevia is a medicinal herb commonly known as sugar leaf under Asteraceae family. Stevia leaves are in growing demand as a natural sweetener, and the health benefi ts of the herb have created an interest among researchers. However, stevia plant is a slow growing herb and biomass yield is low due to slow initial plant growth rate, less number of leaves and small leaf area. In addition, less stevioside activity some times causes poor sugar content in the leaf. The aim of the study is to investigate the effects of kinetin on morpho-physiological and biochemical characteristics of Stevia rebaudiana. Besides that, this study was conducted to determine the effects of kinetin on antioxidant activity of Stevia rebaudiana. The stevia plants were sprayed with 0, 10, 20, 40 and 80 mg/L of kinetin under green house conditions. Parameters such as height of plant, leaf number, area of the leaf, leaf chlorophyll content, chlorophyll fl uorescence, photosynthesis rate, stomatal conductance, total soluble solids, carotene content and antioxidant activity through DPPH assay were measured and determined. The results showed that the application of 10 mg/L kinetin increased plant physiological activities, leaf area, and photosynthetical characteristics of stevia plants. In addition, total soluble solids, carotene content and antioxidant activity were also increased signifi cantly with 10 mg/L kinetin treatment. It can be concluded that spraying with 10 mg/L kinetin twice a week improved morpho-physiological characteristics and increased biochemical properties of stevia plants.