Investigation the effects of different culture media on micropropagation of Abarkooh cypress plant (Cupressus sempervirens L. var. horizontalis)

Abarkooh cypress (Cupressus sempervirens L. var. horizontalis (Mill) Gord) is one of the oldest trees in the world. Because of its prolonged life, the plant has tolerate many adverse environmental conditions, so if this valuable treasure is propagated, it can produce a large plant population with the ability to withstand extreme environmental conditions. Tissue culture is one of the best methods for protection and propagation of in danger and rare plants such as this plant. This study was conducted to determine the best culture media and concentration of BA in micropropagation of Abarkooh cypress plant. In this research, different culture media such as Murashige & Skoog (MS) and modified MS contained ½ MS, ¾ MS, MS without ammonium nitrate, MS with ½ nitrogen, source MS with modified vitamin-1 and 2 group by three concentrations of BA (0, 0.1 and 1 mg/l) in establishment phase and five concentrations (0, 1, 1.5, 2 and 5 mg/l) in proliferation phase were used. Experiments were performed in factorial and completely randomized design with five replications. In establishment phase the highest length and number of shoots as well as the lowest percentage of browning were obtained in ½ MS culture medium. All culture media except MS with ½ nitrogen source, maintained greening degree. By increasing the BA concentration in establishment stage, length of shoots significantly, increased. However, the highest length of shoots was obtained in culture media supplemented by 1 mg/l BA. In all media with modified nitrogen source or without it, length and number of new shoots significantly decreased in compare other culture media. In proliferation phase, the highest number and length of shoots were obtained in ½ MS culture medium supplemented by 2 mg/l BA and the highest greening degree was recorded in cultured explants ½ MS and ¾ MS culture media. According to the results, by increasing BA concentration in proliferation stage, length and number of shoots significantly increased, but greening degree significantly decreased. Generally, proliferation rate, length and number of shoots greatly depended on nutrition of explants and kind of culture medium. According to the results of this study, ½ MS culture medium supplemented by 1 mg/l BA in establishment stage and 2 mg/l BA in proliferation stage, is recommended. Generally, proliferation rate, length and number of shoots greatly depended on nutrition of explants and kind of culture medium. According to the results of this study, ½ MS culture medium supplemented by 1 mg/l BA in establishment stage and 2 mg/l BA in proliferation stage, is recommended.