UV-Rays induced Cytomorphological and biochemical variations in Stevia rebaudiana Bertoni

Abstract Stevia rebaudiana Bertoni is a perennial herb of the Asteraceae family and is highly medicinal in number of ways. Abiotic stress such as UV radiation exposure was reported to have a beneficial effect on morphological traits of the plant. Plantlets of Stevia (4–5 cm) were exposedto UV-B rays with differential time viz. 20, 40, 60, 80, and 100 minutes, respectively along withthe control set. The exposed plantlets were transferred to the greenhouse for further study and growth. After 45 days of plantation, morphological studies were taken out and tabulated. At intermediate doses i.e. , 40 and 60 min, an increase in leaf area, leaf width, leaf length, plant height, internodal length and width of stem have been found in relation to morphological traits while in case of cytological study different chromosomal arrangements were observed viz. scattering, precocious movement, stickiness, unorientation and bridge formation, etc. Hence on the basis of morphological and cytological studies performed on Stevia afterUV irradiation,it was concluded that, shorter exposure of UV-B(40 and 60 min)induced some better morphological traits so that the qualitative and quantitative features of the plant were enhanced.