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Adansonia digitataL. (African baobab), is an important multi-purpose tree, whose distribution is at present limited to wild or semi-domesticated individuals widespread in Africa. Its distribution is threatened by seedling clearance for other land use and potentially by overharvesting induced by growing commercial use of baobab fruit. Recently, efforts have been made to establish baobab domestication and conservation strategies, with mixed results due to the low germinability of baobab seeds, a factor that hinders the possibility of developing commercialA. digitataplantations. Here, micropropagation was tested as a method for clonal propagation of explants fromin vivo-grown seedlings.In vitroshoot multiplication was achieved by enhanced axillary bud proliferation of sterilized two-node segments. Bud break was dependent on cytokinin supply, but the combination of 1.0 or 10.0 μM zeatin riboside and 10.0 μM indole-3-butyric acid (IBA) increased the formation of microshoots after 8 weeks of culture. Regenerated microshoots rooted successfully inin vitronutrient medium containing 10.0 μM IBA and normally grew in a greenhouse after acclimatization. [ABSTRACT FROM AUTHOR]

In order to conserve and multiply the aquatic fernMarsilea quadrifoliaL., in a long-termin vitroprocedure, the effects of different cytokinins, i.e., 6-benzylaminopurine, zeatine riboside, andN6-(2-isopentenyl)adenine, were investigated, varying their concentration and period of supplementation. No clear stimulatory effect on thede novonodes 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 thein vitroHF micropropagation could be useful in the development ofex situconservation programs ofM. quadrifolia, even in order to possibly reintroduce the plants in their natural environment. [ABSTRACT FROM AUTHOR]