Okamura M. et al., Journal of Forest Research 6: 63-66 (2001)
Summary
Embryogenic callus of Quercus acutissima was successfully induced from embryogenic cultures, and plants were regenerated from the callus. The development of the techniques involved will allow mass propagation and gene transformation in this species. Embryogenic cultures were formed from embryonic axis explants (i.e., embryos without cotyledons) excised from immature embryos, after culture on Murashige and Skoog (MS) medium containing indolebutyric acid and benzyladenine. Attempts to induce embryogenic cultures from cotyledon explants were unsuccessful. Embryogenic calli were induced at high frequency from embryogenic cultures on MS medium containing 2,4-dichlorophenoxyacetic acid. However, benzyladenine inhibited embryogenic callus formation. Somatic embryo development from embryogenic calli occurred on MS medium in all of the seven cell lines tested. Germination of somatic embryos was induced on half strength MS medium without plant growth regulators. Finally, acclimated plants growing in soil were obtained.
Objectives
effective embryogenic callus formation and plant recovery from embryogenic caIlus in Q. acutissima.
リオジ
Materials
We collected open pollinated seeds from grafted clones of three plus trees of Q. acutissima (Daigo 3, Kitaibaraki 2, and Tuskuba 2) in the clone bank of the Ibaraki Prefectural Government Forestry Technology Center.
Explant
immature acorns and mature acorns
Initial culture
The pericarps and seed coats were removed and the embryos were surface sterilized in 70% (vol/vol) ethanol for 1 min and 6% (vol/vol) hydrogen peroxide for 15 min, and then rinsed in sterile deionized water in aseptic conditions. Afterwards embryonic axis explants were cultured on MS containing 5 μM BA and 5 μM IBA for embryogenic culture induction.
Shoot multiplication
(Embryogenic callus induction, Somatic embryo induction) Embryogenic calli from embryogenic culture were induced on MS medium supplemented with 5 μM 2,4-D. Then somatic embryos were developed from embryogenic calli on MS medium without plant growth regulators.
Rooting
(Germination of somatic embryos) Somatic embryos germinated on half strength MS medium without any plant growth regulators.
Acclimation
Plantlets were transferred to pots containing vermiculite, and acclimated in the greenhouse.