Optimization of micropropagation of Buxus sempervirens auct non L., an ornamental shrub critically endangered with treatment of BAP and NAA

Common boxwood (Buxus sempervirens auct non L.) is a hard-rooted shrub with slow propagation rate. This plant species is in danger of extinction due to invasion of a type of fungus named Calonectria pseudonaviculata. The purpose of this research was investigation of the effect of different concentrations of BAP and NAA (0, 0.5, 1, 1.5 and 2 mg/L form each two) on micropropagation of B. sempervirens. Sterilization of explants of this species is very difficult. Combined application of disinfectants is proposed. Results of micropropagation showed that the largest number of shoots (6.60/plantlet) was obtained in apical buds expalnts treated with 1 mg l-1 BAP. Maximum number of node (5.50/plantlet) and number of leaf (8.10/plantlet) were obtained in media enriched with 1 mg l-1 BAP along with 0.5 and 2 mg l-1 NAA, respectively. The highest root length (10.15 cm/plantlet) was obtained in explants treated with 1 mg l-1 BAP along with 1 mg l-1 NAA. Also, the largest number of root (8.20/plantlet) was calculated in explants treated with 0.5 mg l-1 BAP together with 1 mg l-1 NAA. After propagation, plantlets were transferred to a bed containing peat and perlite with ratio of 1:1 for acclimatization. About 90% of them were recovered and survived. These survived plantlets were morphologically similar to the mother plants.