Effect of trees age and light on Betula litwinowii callogenesis and betulin induced in vitro conditions

Plants due to their secondary metabolites have world value and wide applications in various fields of technology. Birch genus (Betula) contains secondary metabolites، especially terpenes which have preventive properties for skin cancer، HIV virus، hepatitis، and malaria. Finding a suitable alternative for pharmaceutical industry is essential due to the limited mother trees and danger of extinction of the mentioned species. Considering the problems associated with crop production and forestry، other methods such as in vitro plantation by applying triggers to obtain the herbal ingredients can be used. The purpose of this research was to evaluate the effects of light and dark on Betulin production in four month calli of in vitro produced B. litwinowii. Explants were prepared by leaves of 25 years old mother plants and 5 years old seedlings during summer from Sangdeh site. They were cultured on WPM plantation medium at light and dark conditions. For analysis of callus production a t- independent test with 5 replicates was used، Analysis of Betulin rate was used using a calibration curve that was obtained by injection of standard solutions using HPLC system. Results showed that light conditions (16 hours light and 8 hours dark) with white light intensity of 1000-1500 lux were essential for callogenesis explants and Betulin quantity was higher in explants prepared from older mother plants.