| In this study,Cymbidium ensifolium,one of the chinese orchid was the research object and it was observed and recorded the development morphology of capsule,seed and embryo in different time after pollination,and seed germination process;the seeds of C.ensifolium was used as material to explore the effects of seed developmental status,basic cultivation methods,illumination and plant growth substances on germination;in addition,differentiation of C.ensifolium rhizomes was explored with different growth period and cutting size rhizomes under the treatment of various plant growth substances,such as NAA,6-BA and TDZ,to provide a reference for improving the in vitro cultivation efficiency of C.ensifolium.The main results of this study are as follows:1.Development of C.ensifolium capsule,seed embryo and seed germination process was observed.The results showed that after pollination,the diameter of capsules continued to increase and its color changed to dark green;the labellum became brown and withered before petals and sepals after pollination within 5 and 30 day,respectively.The stigma of column curved inward and the color changed gradually from pale yellow to dark green;ovary of C.ensifolium is composed of three carpels and the parietal placenta has developed completely before pollination;there are many irregular finger protrusions on the placenta;60 days after pollination(DAP)the zygote developed into an early globular embryo and by 480 DAP it has fully matured and part of the suspensor has not degenerated;the germination time of C.ensifolium seeds is discrepancy and it takes at least about 30 months from sowing to seedling establishment,many of them have not germinated after two years of cultivation.The germination process of seed is divided into five stages: not germination,swelling,rupture of testa,elongation and branching,the time from seed swelling to each stage is about 1-3months.2.These are significant effects on C.ensifolium seed germination of that about the number of DAP,basic cultivation methods,illumination and plant growth substances.Theresearch have shown that: seeds did not germinate at 60 DAP,but the germinating number of seeds in 360 and 480 DAP was lower than that of 90 and 270 DAP;the effect of 1/2MS medium on seed germination is better than that of MS and 1/4MS medium;the germination rate of seeds in liquid medium is significantly higher than on solid medium up to 39.56%;illumination is not necessary for the seed germination,and the seed germination rate of 360 DAP can be up to 96.27% in 1/2MS+25g/L sucrose+2mg/L 6-BA in dark;both NAA and6-BA can significantly increase seed germination,and 6-BA is more conducive to growth after germination;in addition,research with ethylene have shown that low concentrations of ethylene(1?l/L and 5?l/L)can inhibit seed germination,while 10?l/L and 20?l/L of ethylene gas cause the germination rate of C.ensifolium seeds were similar to the control group without ethylene.3.There are significant differences in the differentiation efficiency of C.ensifolium rhizomes with different developmental status and cutting size.For rhizomes with different developmental sizes,medium and large rhizomes had higher germination rates on 1/2MS +25g/L sucrose + 2.0 mg/L 6-BA + 0.2mg/L NAA up to 492% and 488%,respectively;while the rooting rate of large rhizomes is smaller,and the medium size is higher at 260%;When cutting large rhizomes for tissue culture,larger cutting rhizomes on 1/2MS + 25g/L sucrose +0.5mg/L 6-BA + 0.5mg/L NAA medium are the most effective for budding and rooting,and the differentiation rate can reach to 1107% and 227%,respectively. |
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