The phloroglucinol, a supplement in the culture medium, has proved itself very efficient at some species which have a difficult reaction to the culture in vitro (strelizia, musa, magnolia, some species from the Liliaceous family, etc.). In the particular case studied by us, Solanum tuberosum L, the phloroglucinol added in MS medium in two doses (100 and 200 mg/l) has stimulated the greatest percentage of regeneration of tubers from potato minitubers from Desirée species (detached from neoplantules obtained in vitro). The results have proved to be dependent of the dose of phloroglucinol, of the composition of the medium and last, but not least of the specie. The formation of the great number of tubers in vitro has been obtained based on the variants with the concentration of 200 mg/l Ph., in the presence of zeatine, the differentiation of the minitubers on this medium took place after 30 days of culture in vitro. We have fallowed the rhythm of the neoformation of the potato tubers (see table 2) and we have concluded that the percentage of tuberization is 50% after two months and over 80% after three months on the 200mg/l phloroglucinol mediums with a plus of zeatine (Z) and benziladenine (BA). On the other variants the percentage reaches only 25-30%, and on the martor (C o ) only 10-15%. The double concentration of phloroglucinol (200mg/l) in the specified combinations in table 1, (C 4 , C 6,. C 8 , C 10 ), also stimulates  the regeneration of plants, completely conformed with the corresponding radicular system, and the formation of neotubers takes place along the strains, especially in the zone of the node, but also at the base of the plants.

phloroglucinol; apex; minitubers; tuberisation; neoformation; regeneration; organogenesis

Presentation: oral