Somatic embryogenesis and plant regeneration from immature embryos of five families of Quercus acutissima

Immature embryos of sawtooth oak (Quercus acutissima Carruth.) were obtained from five seed families and cultured on modified Murashige and Skoog nutrient medium containing 1 g/l l-glutamine and 5 mM proline and supplemented with 1.0 mg/l indole-3-butyric acid and 1.0 mg/l 6-benzylaminopurine. The frequency of somatic embryogenesis from immature embryos was a function of the collection date and seed family. The highest frequency of explants forming somatic embryos was obtained with seeds of family Chungnam 11, i.e. 7 weeks post-fertilization (90.9%) and 9 weeks post-fertilization (91.2%). No response was shown by families Chungnam 14, 15 and Jeonbook 29 (0%), at 10 weeks post fertilization. During germination, the highest frequency of epicotyl formation was obtained with Chungnam 11 (44.0%) or Chungnam 15 (43.5%), and the highest rate of radicle formation was shown by Chungnam 11 (26.1%). The most responsive seed family with respect to the formation of both epicotyl (43.5%) and radicle (26.1%) was Chungnam 11. Twenty plantlets were transplanted to a perlite:peatmoss:vermiculite (1:1:1) soil mixture, and 8 plants survived in the field. Received: 6 December 1996 / Revised version received: 18 April 1997 / Accepted: 10 May 1997