Hormonal Responses of Petioles and Embryos in Ginkgo biloba Cultures
摘要
Petioles and embryos of Ginkgo biloba were cultured on modified Linsmaier & Skoog medium supplemented with various kinds and concentrations of auxins and cytokinins. Calli were easily obtained on the medium supplemented with various combinations of 2,4-dichlorophenoxyacetic acid or naphthaleneacetic acid as an auxin, and kinetin or 6-benzyladenine as a cytokinin. The calli grew rapidly and were able to be subcultured on the same medium. These calli were white in color in the dark, but exposed to light, they easily changed to green. Organogenesis was not observed in petiole explants, but embryos excised from the seeds immediately after their falling to the ground showed germination and leaf expansion on the medium supplemented with indoleacetic acid (IAA) or indolebutyric acid (IBA) alone. When embryos excised from the seeds stored at 3℃ for about 3 months were used, they germinated and seedlings were obtained not only on IAA or IBA containing medium but also on a hormone-free one. Redifferentiation from calli was not seen by combining of growth regulators or modifying the mineral salt in the medium.