Abstract:

Immature embryos of Black Locust(Robinia pseudoacacia) were used as explants to study effects of immature zygotic embryo age, as well as the kind and concentration of plant growth regulators in culture media on callus and somatic embryo induction with an orthogonal experiment. The results showed that seeds collected 8 weeks(about 55 days) post-anthesis had the highest ability to initiate embryogenic cultures. The best callus initiation medium was MS+2,4-D 5.0 mg·L^-1+ BA 0.5 mg·L^-1, with which the highest callus induction rate, 95.42%±0.02%, was obtained. The best somatic embryogenesis medium was MS+NAA 0.5 mg·L^-1+BA 0.5mg·L^-1+Glutamine 250 mg·L^-1+Casein acid hydrolysate 500 mg·L^-1, and produced the highest direct and indirect somatic embryogenic frequency of 92.20%±0.12% and 90.73%±0.49%, respectively. Once globular-stage embryo formed, somatic embryos then matured and germinated to develop plantlets by transferring to the same medium without plant growth regulators.

Key words: Robinia pseudoacacia, immature zygotic embryo, embryogenic callus, somatic embryo, plant regeneration