Studies On Plant Regeneration And Tetraploid Induction Of Polygonum Capitatum

Polygonum capitatum is a herb plant which belongs to Polygonacea, Polygonum and it is widespread in China. With the characteristics of being drought and cold resistant, it usually lives in warm and moist places with limited light. Actually, P. capitatum has a long history of being used as a civil medicine to treat urinary system infection and rheumatism in Guizhou Province because of its plenty of chemical constituents such as flavonoid, phenolic acids and organic acids. However, the accessions deficiency hinders its mass production. Therefore, to achieve its mass production, it is very necessary to establish the P.capitatum regeneration system in order to nurture a vast number of regular plantlets, and to combine the issue culture and in vitro mutagenesis technology to induce polyploid plants. Finally, a new species of high quality with characteristics of being strong, vigorous, and highly resistant and an increased synthesis rate in effective composition can be cultivated.This study analyzed the influence of two explants (leaf and stem), disinfection methods, culture media type and plant growth regulators on the differentiation and inducement of P. capitatum callus, and discussed the utilization of colchicines on different tissues or organs of P. capitatum in different ways in order to acquire the best approach of Mutagenesis and tetraploid plant. At last, a comparison was conducted to analyze the morphology, cytology and resistance traits between diploid plant and tetraploid plant, and also to provide some basic information for the study of Polygonum breeding at the same time.The main results were summarized as follows: 1. The best two disinfection groups had been identified during the process of two P. capitatum explants’ disinfecting. After using70%alcohol disinfection10seconds,One is the leaf processed by0.15%HgCl2in6minutes with16.67%contamination and19%death, and the other is the stem processed by10%NaClO in9minutes with13.33%contamination and13.33%death.2. Compared with other explants, the stem callus had a better inducement effect in the regeneration system of P. capitatum. The MS media was proved to be the most suitable culture media among that different culture medium. In the meantime, the media with6-BA (1.0mg/L) and NAA (0.3mg/L) was good for the callus formation with73.33%leaf induction and86.67%stem induction; MS with the addition of6-BA (4mg/L) and NAA (0.2mg/L) was found to be the best combination for reproduction.3. There were also vitrification and deformity besides the callus’ normal generation, and the activated carbon could restrain brown stain in the culture media. There was only6.80%browning in the addition of100mg/L activated carbon.83.33%callus’ adventitious buds were induced in the combination of6-BA (8mg/L) and IB A (0.1mg/L) with the average number of adventitious buds5.1, and a regenerated P. capitatum plant was acquired.4. Five different ways were used to process different tissues and organs when the colchicine was used as a chemical inducement to get polyploid P. capitatum plants and all the variants were chimaeras. Soaking and semaring after the pre-cultivation worked better.Especially48h at0.2%concentration of colchicines treatment worked,the mutation rate was33.33%5. The morphology and anatomy studies of variation plants indicated that the polyploidy plants tended to have stronger stipes, thicker leaves with spongy and palisade tissues, more leaf trichomes, bigger guard cells and smaller stoma number per unit area with the increased epithelial cells. The improved wall degradation hypotonic flame drying method showed that the chromosome number of variation plants is2n=4x=48and the diploid control group is2n=2x=24.6. The comparison of some physiological characteristics of the tetraploid plants and diploid plants of P. capitatum indicated that the organic material and physiological character of tetraploid plants had significant change in many aspects such as the obviously increased chlorophyll, limited water holding capacity growth, the cell membrane injury rate and electrolyte leakage rate which decreased greatly. The drought-tolerance and heat-resistance of tatraploid plants were also stronger than diploid palnts in P. capitatum.