In Vitro Culture Of Zygotic Embryo In Quercus Liaotungensis Koidz.

Quercus liaotungensis Koidz. is a species of the genus Quercus in the Fagaceae family, and is of high economic and ecological values. Q. liaotungensis is usually propagated by seeds. However, the acorns are sensitive to be damaged by insects, will not endure the storage and there is a significant alternate bearing phenomenon, and it is very difficult to propagate by conventional cutting method, all of which are not in favor of the forestation and exploration of Q. liaotungensis. Plant tissue culture holds promise to overcome these problems Therefore, it is essential to develop in vitro culture and plant regeneration techniques Q. liaotungensis.In this study, techniques of organogenesis and somatic embryogenesis for Q. liaotungensis were first established by mature and immature embryo culture, respectively; some factors influencing organogenesis and somatic embryogenesis of Q. liaotungensis were analyzed. This study is of great significance not only for the establishment of micropropagation techniques for Q. liaotungensis but also for in vitro culture for other Quercus species. The main conclusions obtained from the study are as follows.1. Induction of multiple shoots and plant regeneration of Q. liaotungensis with mature zygotic embryo as explants.(1) Effects of different media and hormones on the induction of adventitious shoots were significantly different. The best medium was MS medium with the best hormone combination 1.0 mg/L 6-BA+0.5 mg/L 2,4-D. The induction rate of this combination for multiple shoots was highest and up to 71.7%.(2) The impact of hormones on the proliferation of adventitious shoots was significantly different. Optimal proliferation medium and hormone combination was MS+1.0 mg/L 6-BA+0.5 mg/L NAA+0.5 mg/L GA3 and the highest proliferation factor is 4.3.(3) A lower macroelements in the rooting medium tended to have a better rooting effect. The best rooting medium was 1/2MS medium with the best hormone concentration 0.5 mg/L NAA and sucrose concentration of 30 g/L. The roots grew robustly.The rooting rate was up to 77.8% and root length was about 4.3cm.2. Induction of somatic embryos of Q. liaotungensis with immature zygotic embryo as explants.(1) The best medium and hormone combination in induction of somatic embryo was MS +1.0mg/L6-BA+0.1 mg/L2,4D, with the highest induction rate 86.7%.(2) Moderately lower hormone concentrations tended to be good for the proliferation of somatic embryos. The best combination of medium and hormone was MS+0.1 mg/L 6-BA +0.01 mg/L NAA. The highest proliferation rate was 93.3%. (3) In somatic embryo maturation experiment, appropriately increasing sucrose concentration enhanced somatic embryo maturation rate. There were less distorting mature embryos with 5% sucrose. The best combination of medium and hormone for somatic embryo maturation was MS+0.5 mg/L 6-BA+0.3 mg/L ABA, with the maximum maturity rate of 71.1%.(4) In somatic embryo germination experiments, the best medium and hormone combination was 1/2MS+0.5 mg/L 6-BA+0.2 mg/L IBA. The highest rooting rate was 44.4% and the average root length was 4.1cm.(5) In embryo germination tests, the best medium and hormone combination was 1/2MS +0.5 mg/L 6-BA+0.5 mg/L NAA, with the highest germination rate of 8.9%.