In vitro micropropagation of the aquatic fern Marsilea quadrifolia L. and genetic stability assessment by RAPD markers

In order to conserve and multiply the aquatic fern Marsilea quadrifolia L., in a long-term in vitro procedure, the effects of different cytokinins, i.e., 6-benzylaminopurine, zeatine riboside, and N6-(2-isopentenyl)adenine, were investigated, varying their concentration and period of supplementation. No clear stimulatory effect on the de novo nodes produced per explant was detected when compared with hormone-free (HF) condition. On the contrary, the rhizome explant micropropagation was inhibited, the inhibition decreasing with the decreasing strength of cytokinins, though without reaching any significant enhancement. Since, as a consequence of the tissue culture procedure, the occurrence of somaclonal variation may introduce genomic alterations, genetic stability was assessed by random amplified polymorphic DNA (RAPD) analysis by comparing eight randomly selected micropropagated plants derived from repeated subcultures, with donor plant. Eighteen different primers generated 189 bands ranging from 100 to 3250 bp, and the same banding profiles were exhibited. No genomic alterations were evidenced in any of the micropropagated plants. Well-developed micropropagated plants were also successfully acclimatized under greenhouse condition. These positive results suggest that the in vitro HF micropropagation could be useful in the development of ex situ conservation programs of M. quadrifolia, even in order to possibly reintroduce the plants in their natural environment.