In vitro microbial contaminations are the most serious problems in plant tissue culture. Initial attempts for micropropagation of Dionysia tapetodes, a beautiful alpine cushion plant from north-east Iran, led to 100% explants contamination. Hence, the present study was conducted to develop an efficient surface sterilization protocol for in vitro culture of field collected D. tapetodes using combinations of different disinfection agents including sodium hypochlorite (NaOCl), ethanol and mercuric chloride (HgCl2) in different concentrations and exposure time. The most effective sterilization treatment with 91.6% healthy explants was the application of 0.1% mercuric chloride for 4 min. However, HgCl2 in higher concentration (0.2%) was toxic to explants tissues and resulted in 41.66% necrosis. Moreover, the results indicated that NaOCl in spite of being a general disinfectant in tissue culture studies was not as effective as HgCl2 in elimination of microbial contaminations, led to 75% total infection when used in 3% concentrations for 15 min. The current experiment represented a potential method for disinfection of D. tapetodes and provided aseptic and clean explants for future in vitro culture studies.

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