PLANT REGENERATION FROM DIFFERENT EXPLANT TYPES OF STREPTOCARPUS SPEC. IN VITRO

Abstract

In order to develop an in vitro regeneration protocol for different Streptocarpus species, we investigated the effects of three factors: surface sterilization, regeneration medium and explant type. For surface sterilization the influence of an ethanol (70%) treatment for 30 s was tested, before the explants were immersed in 1.5% sodium hypochlorite for 10 min. Our experiments showed no significant difference regarding contamination of explants between the surface sterilization with and without ethanol. On the other hand, the treatment with 70% ethanol led to damage of the leaf explants regarding regeneration, especially the number of shootlets. The variation of indole acetic acid (IAA) and benzylaminopurine (BAP) concentrations in the regeneration medium revealed, that a combination of 1.0 mg L IAA and 1.0 mg L -1 BAP was most efficient for shoot regeneration in three species (S1, S3, S4). However, the best quality and regeneration response of the fourth species (S7) was obtained with 1.0 mg L -1 IAA and 0.1 mg L -1 BAP. The differences of the most suitable combination of phytohormones showed, that it was not possible to designate a uniform optimal medium for all of Streptocarpus species. In addition, different explant types were compared. Taking into consideration the regeneration intensity, the expenditure of time for explant preparation and material costs, we concluded that the most suitable explant type were leaf blade explants.