Factors affecting shoot regeneration from leaf and hypocotyl explants of Platanus acerifolia Willd.

Effects of different genotypes,PGRs,illumination conditions and position of explants on adventitious shoot regeneration from hypocotyl and/or leaf of Platanus acerifolia were investigated.The results indicated that the ratio of 6-BA to IBA in the medium influenced shoot regeneration of hypocotyl segments and 6-BA:IBA20:1 gave a better effect;Shoot regeneration from leaf explants was significantly different among four different genotypes investigated,with the highest regeneration rate obtained for leaf explants of genotype PH2,and TDZ was less effective than 6-BA to induce shoot regeneration from PH2 leaves.Maintaining the cultures in darkness for the first month promoted shoot regeneration of hypocotyl explants to some extent,but leaves incubated in darkness regenerated less shoots evidently;Light intensity of 50-100 lx was favorable to shoot regeneration.Significant differences of regeneration capability existed among different sections of hypocotyl and position of leaves,and the hypocotyl section adjacent to the cotyledons and the uppermost two leaves of the shoots showed better regeneration capability than the lower sections and leaves.Furthermore,shoot regeneration of the intact leaves wounded by three cuts was more efficient than that of severed leaf segments,indicating that the ECIWO/holographic phenomenon existed during in vitro culture of hypocotyls and leaves of P.acerifolia.