Production and characterization of tissue cultures of four crocus species from the Carpathian Basin

We aimed to produce tissue cultures and plant regeneration from endangered Crocus species: C. scepusiensis, C. tommasinianus, C. vittatus (“Verni” series of the genus) and C. banaticus. For initiation of cultures we used a plant growth regulator (PGR) combination used for in vitro culture of saffron and its relatives: 10 mg L-1 α-naphthaleneacetic acid (NAA) and 1 mg L-1 6-benzyladenine (BA). Shoot tips of young seedlings (C. scepusiensis) and corms (for the rest of species) were used as explants. C. scepusiensis explants developed into organogenic calli. On media with decreased NAA and with or without increased BA concentration, calli produced stigma-like structures and/or shoots and whole plants. In the other species, callus initiation medium induced callus formation with abundant somatic embryos. In C. tommasinianus, embryos developed shoots when auxin content of medium was decreased. In C. banaticus, a decrease of auxin with or without an increase in cytokinin content led to shoot or whole plant regeneration, as in C. scepusiensis. In the case of C. vittatus and C. banaticus, initiation and/or maintenance of cultures on indole-3-butyric acid (IBA) and increased sucrose concentration stimulated whole plant regeneration and in vitro cormlet development. C. scepusiensis and the rest of cultures (organogenic vs. embryogenic) differed at the biochemical level: C. scepusiensis cultures had higher (yet still low) enzymatic antioxidant (catalase, peroxidase) activities. With respect to catalase isoenzyme patterns, C. banaticus was different from the rest of cultures, demonstrating its distinct taxonomical position. Besides germplasm preservation use of the present cultures, they have a potential biotechnological value.