Abstract:

Adventitious buds were induced from the excised mature zygotic embryos of Ponderosa Pine (Pinus ponderosa). The highest induction rate (65.8%) of adventitious buds was obtained with 10 fold multiplication at the highest and 7\|fold multiplication at an average when mature zygotic embryos were cultured on GD + 9.85～19.70 μmol·L^-1 6BA+ 0.0～14.42 μmol·L^-1 NAA. The adventitious buds were initiated or formed directly from the cotyledons. Additional NAA inhibited the formation of adventitious buds. Buds proliferation and elongation were achieved on 1/2GD and 1/2SH without growth regulators. A proper amount of activated charcoal promoted adventitious buds elongation and root growth. The adventitious shoots of Ponderosa Pine were used to induce adventitious roots on 1/2GD and 1/2SH media supplemented with different concentrations of NAA and GA3. The results showed that NAA played a determinative role in initiating the adventitious roots. Sixteen point seven percent (16.7%) of adventitious shoots was rooted on 1/2GD with 28.84 μmol·L^-1 NAA+4.17 μmol·L^-1 GA3. In the present paper, the experimental results showed that roots were successfully induced from cultured mature zygotic embryos of Ponderosa Pine.

Key words: Ponderosa Pine(Pinus ponderosa), mature zygotic embryos, in vitro, plantlet regeneration