An improved procedure for in vivo and in vitro propagation of Buxus hyrcana , an ornamental shrub critically at risk of extinction

摘要

The ornamental shrub, Buxus hyrcana is a threatened species due to the attacks of some pathogens. Rooting of this valuable shrub using propagation techniques such as cuttings is very slow. The present study was carried out to evaluate the effect of different concentrations of indole-3-butyric acid (IBA) and kinetin (KIN) on rooting of semi-hardwood cuttings and in vitro propagation of B. hyrcana. In propagation experiment, the basal region of the cuttings was treated with IBA and KIN solutions (0.00, 500, 1000 and 2000 mg/l of each). The cuttings were then transferred to rooting beds filled with perlite. After a rooting period of 60 days, some morphological parameters were measured. The 500 mg/l KIN along with 1000 mg/l IBA induced the largest number of roots (16.80 per plantlet). A maximum of 8.16 cm root length per plantlet was obtained with 1000 mg/l IBA together with 1000 mg/l KIN. The largest number of leaves (105.00) was observed in rooted stem cuttings treated with 2000 mg/l IBA along with 1000 mg/l KIN. In tissue culture experiment, the medium enriched with 2.00 mg/l KIN together with 0.50 mg/l IBA was found to be suitable for obtaining the maximum leaf number (11.43 per explant). A higher rooting frequency was also observed with the highest rooting of 6.50 roots per cutting achieved in plantlets grown in a medium supplemented with KIN and IBA (1.00 mg/l each). In vitro rooted plantlets were cultivated in plastic pots containing peat and perlite (in ratio of 1 : 1). The plantlets were successfully acclimatized in an adaptation greenhouse with a survival rate of 95% exhibiting normal developmental patterns.