| Cornus officinalis Sieb. Et Zucc.(Cornaceae) is a deciduous arbor with more than 200 years cultivated history in China. Its fruits are used as a precious traditional Chinese medicine which contain abundant chemical componets, such as saponins, phenol constituents, organic acids, amino acid, vitamins and many kinds of ore elements.The experiment with different explants of Cornus officinalis Sieb. Et Zucc. established systematically its tissue culture and plant regeneration systems, investigated the structure of leaf of its normal and hyperhydric shoot, and studied the occurrence and the methods of preventing the hyperhydric shoots from forming In addition, the effective components were determinated.The main results were as follows:1.With different explants including shoots with axillary buds, floral receptacle and floral shoot, the research established their tissue culture and plant regeneration systems, and the main results showed:(1) The regeneration system of Cornus officinalis Sieb. Et Zucc. was set up from shoots with axillary buds. The suitable medium for shoots of Cornus officinalis Sieb. Et Zucc. was 1/2MS+BAlmg/L+IBA0.5mg/L,on which a few buds may multiplied; and 1/2 MS+ BA 0.5mg/L+IBA 0.05mg/L was suitable for buds multiplication on a large scale, on which the buds multiplication rate was about 5.3. According to the result, the micro-propagation system of Cornus officinalis Sieb. Et Zucc. was established, and a lot of test-tube seedling can be obtained.(2) Adventitious buds were regenerated from callus of leaves of Cornus officinalis Sieb. Et Zucc. The suitable medium was l/2MS+BA2-4mg/L+IBA0. 5-1.0mg/L and 1/2MS +KT2-4 mg/L+2,4-D0.5-1.0g/L. When the concentration of BA was 2-4mg/L and IBA was 0.5-1.0mg/L, the induction frequency of callus can be more than 90%; and when the concentration of KT was 4 mg/L and 2,4-D was 1.0 mg/L, the induction frequency of callus can amount to 82.2%.The obtained callus was different, some are fragile, grey and hard to differentiate, while others are hard, white or dark-green and can produce buds.(3) Adventitious buds were regenerated from floral receptacle and floral shoot of Cornus officinalis Sieb. Et Zucc. In this experiment, both floral receptacle and floral shoot were theappropriate explants to study tissue culture and the regeneration system was established. The induction frequency of callus was 100% when the floral receptacle was cultured on the 1/2 MS medium supplemented with BA1.0mg/L and 2,4-D0.5 mg/L; and the induction frequency of callus of floral shoot can be 96.2% on the same medium. The callus can multiply on a large scale and a few adventitious buds can be induced from callus on the medium of 1/2 MS +BA 0.5 mg/L+BA 0.01-0.05 mg/L after 2-3 months.(4)Adventitious buds were induced from callus on the medium of l/2MS+BAl-2mg/L+IBA0.01-0.05mg/L. After 2-3 generations, the adventitious buds can be induced from the surface of the callus. The formation rate of adventitious buds from leaf callus reached 44% and those from floral tissue were 54.8%.(5)The shoots that reached l-2cm were detached and transferred to 1/2MS medium supplemented with l-2mg/L IBA for rooting. About 20% shoots produced roots and formed plantlets.2.The structure of normal and hyperhydric the plantlets was compared by electron scanning microscopy, optics microscopy and transmission electron microscopy. The structure of leaf of the normal plantlets was similar to that of plants found in the field, but the great change occurred in that of hyperhydric plantlets.3.The experiment studied the ways of occurrence of hyperhydric shoots and found out the methods of preventing the normal shoots from forming hyperhydric shoots of Cormis officinalis Sieb. Et Zucc. The main results were as follows:(1) The results showed that many hyperhydric shoots were produced for adding higher concentration of BA in the medium. When the concentration of BA was 5mg/L, the production frequency of hyperhydric shoots can be more than 50%. From the cultural results, it was found t...
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