Studies On Germplasm Resources Of Houttuynia Thunb

HERBA HOUTTYNIAE, the whole plant of Houttuynia cordata Thunb., is a kind of traditional Chinese medicine and also a kind of delicious vegetable. It is the raw material resources of Yuxingcao injecting liquid. In current time, pharmacological experiments had proved that it had the function of antibacteria, anti-virus and diuresis, and could enhance body immunity. Now it had been identified as one of a kind of most potential resources which could be used as both medicine and food by National Health Department, thus attracted the sight of many people. Houttuynia cordata Thunb. is the only species in Houttuynia Thunb. according to many Florae. In recent years, a new species in Houttuynia Thunb.named as Houttuynia emeiensis Z.Y. Zhu et S. L. Zhang was found at Emei Mountain. It was called commonly as white Yuxingcao, which was also used as vegetable and HERBA HOUTTYNIAE in Emei and Leshan regions.HERBA HOUTTYNIAE mainly depended on wild resources. However, with Yuxingcao injecting liquid market increasing, and many new relative products emerging, the reserves of wild H. cordata Thunb.decreased every year because of destroying collection. Now the wild resources could not adapt to the product requirements, and cultivated in large scale was in great need. Germplasm resources were the material foundation of breeding, and the sources of finding and utilizing gene resources. Analysis on germplasm resources diversity would provide important information on evaluating the developing prospect, introducing new species, cultivating and protecting resources. In the mean time, the evaluation on germplasm resources was the guarantee of carrying on Good Agricultural Practice(GAP). The extensive and profound research on germplasm resources would provide good material and theoretical foundation on producing green Chinese medicine. This study evaluated systematically the germplasm resources of H. Thunb. at cytology, is ozymes and molecular level. This study also carried on breeding of new species and research on necessary and synthetical cultivated technology. The main results showed as following:1. The cytology observation results showed that the chromosome numbers of H. cordata Thunb. varied from 36 to 126. Of which, the number of 36, 54, 72 and 126 were found for the first time. So was the chromosome number of H. emeiensis Z.Y. Zhu et S. L. Zhang 36. Within 90 different H. cordata Thunb. accessions, 81 was the most frequent chromosome numbers. The basic number of H. Thunb. was considered to bex=9. It belonged to typical polyploid compound populations. This study also found that there existed cytomixis in H. cordata Thunb. during diad, tetrads and microspores periods, The chromatin transferred through plasmodesma, conjugation opening and conjugation tube.2. The analysis on peroxidase and esterase isozymes of the germplasm resources of Houttuynia Thunb. showed that there existed plentiful isozymes variations among the germplasm resources of H. Thunb. The cultivated accessions had the same isozymes band types as the wild ones. There were 6 different types of peroxidase isozymse bands and 10 different esterase isozymes band totally. Each peroxidase band type was composed of 4 to 6 bands, with esterase isozymes 5 to 8 bands. There was no significant difference between H. cordata Thunb.and H. emeiensis Z.Y. Zhu et S. L. Zhang accessions in their isozymes bands types. The number of peroxidase and esterase isozymes bands increased with the chromosome number, so did the band types. The results also showed that the number of peroxidase isozymes bands in northern areas was somewhat higher than that in southern areas. However, esterase isozymes band types had no geographic differences.3. The genetic diversity of 92 Houttuynia Thunb. accessions were tested by using RAPD markers. Of 34 10-mer arbitrary primers, 32 of them (94.1%) were found to amplify polymorphic products. A total of 200 products were amplified. Of which, 93.5% products were found to be polymorphic. 5.8 polymorphic bands were amplified by each polymorphic prime...