Tissue culture and phytochemical studies of Podophyllum, Diphylleia and Passiflora species
Silva, Cláudia Gontijo (2000) Tissue culture and phytochemical studies of Podophyllum, Diphylleia and Passiflora species. PhD thesis, University of Nottingham.
Lignans are the most important secondary metabolites known in Podophyllum hexandrum and Diphylleia cymosa. Tissue cultures studies were carried out in order to preserve and increase these germplasms. Somatic embryogenesis in both species was obtained and confirmed histologically. In D. cymosa, somatic embryos were induced from leaf and petiole-derived callus. The formation of abnormal embryos, with fused cotyledons, was influenced by the growth regulators used. Embryo maturation was confirmed histochemically through the identification of starch granules in the cotyledons. Regeneration was dependent on the culture media. Somatic embryogenesis in P. hexandrum was achieved through embryogenic cell suspension cultures from root-derived callus. Organogenesis via adventitious bud formation led to plant regeneration in liquid medium. Phenotypically normal plants were recovered. The regenerant showed the somatic chromosome number of 2n=2x=12, although some chromosomes were morphologically abnormal. The recalcitrance of P. hexandrum towards Agrobacterium-mediated transformation was demonstrated with different strains of both A. tumefaciens and A. rhizogenes. The presence of cytotoxic lignans in P. hexandrum may have a role in the inactivation of the bacteria.
Actions (Archive Staff Only)