Stem Tissue Culture of Pinus elliottii × Pinus caribaea

Using tender stems of the current-year in 5-year-old P. elliottii × P. caribaea as explants and exploiting orthogonal experiments, we optimized the growth conditions of Pinus elliottii × Pinus caribaea in vitro and successfully obtained the plantlets. We found that: (1) as explants, fragments at 1.5~3.0 cm from top to bottom of stems that cultured in DCR media supplemented with 2.0 mg/L N6-benzyladenine (6-BA), 0.10 mg/L alpha-naphthyl acetic acid (NAA) and 30 g/L sucrose have the best early differentiation rate of 43.7%; (2) among the tested conditions, DCR media supplemented with 2.5 mg/L 6-BA and 0.2 mg/L NAA is most suitable for propagation of adventitious buds giving a propagation rate and fold of 96.7% and 6.2, respectively, (3) DCR media supplemented with 0.3 mg/L NAA, 1.5 g/L activated carbon and 20 g/L sucrose is best for elongation of adventitious buds giving propagation rate of 444.6%; (4) transplantation of seedlings to 1/2 DCR media supplemented with 2.0 mg/L NAA and cultured in dark for 10 days followed by illumination 12 h/d with 40 μmol·m-2·s-1 intensity resulted as high as 55.3% rooting rate.