| Ophiopogon japonicas (L.f.) Ker-Gawl is a type of Chinese herbal medicine which recorded in all previous edition of Chinese Pharmacopoeia. It is often used to nourish yin and moisten lung, promote the production of body fluid and saliva, clear away the heart, relieve restlessness.In present study, O. japonicas was studied in following aspects: 1. Collection of germplasmic resources of O. japonicas distributed in different regions in Sichuan, and comparison on the external characters of different strains or related plants of O. japonicas. 2. Karyotype analysis on chromosome in different strains of O. japonicas. 3. The genetic relationship of different strains of O. japonicas by using the method of ISSR. The results obtained are as follows:1. There is great difference on morphology characters of wild O. japonicas in different populations. After one-year planting in the same field, morphologic characters of wild O. japonicas in different populations were trend to be identical. Among all materials, the root weight of per plant of No.1, No.4, No.7, No. 11 and No.19 obviously is greater than that of No.12, No.13, cultivated in Santai, Sichuan. It is clearly revealed that excellent wild resources of O. japonicas were existed in natural condition.2. The results of Karyotype analysis on chromosome in different populations of O. japonicas indicate that the number of chromosome is 68 and the basic chromosome number is 17. According to size of No.1 metacentric chromosome obviously differs from that of No.2 chromosome, it is identified that O. japonicas might be tetraploid. From No.2 to No. 17, size of chromosome gradually decreased. Most chromosomes were consisted by metacentric chromosome, submetacentric chromosome and acrocentric chromosome. However, there are two populations in which do not contain any acrocentric chromosome. The chromosomes of O. japonicas in different populations are different in respect of the range of relative length, ratio of longest and shortest chromosome and average arm ratio. There is not relationship between the karyotype of O. japonicas and geographic distribution of populations. It is difficult to establish regular link between diversity of Karyotype and that of appearance. It is discovered that Karyotype of artificial cultivated No.12 is 2C, and it is characterized by asymmetry comparing to other Karyotype 2B, which might be evolution and is coincidence with theory of Karyotype evolution. Study from collection environment of O. japonicas, No.12 and other populations which Karyotype are also 2C grow in the bamboo forest. Most populations of Karyotype 2B, however, grow in the private farm plots and surrounding houses, or ditches and hillsides.3. 8 polymorphic primers from 96 ISSR primers used to amplify the DNA of 20 samples of wild populations of O. japonicas, 78 DNA fragments was obtained , most of which are distributed between 0.2kb to 2 kb. 73 polymorlhic bands were found and polymorphic frequencu was 93.6%. every primer amplifies approximately 6 to 13 fragments with an average of 9.8 fragments for each primer. The genetic distance ranges from 0.051 to 0.564 with average of 0.331. The results demonstrate that there is high genetic differentiation among the population of O. japonicas. Cluster was carried out based on genetic relationship and the correlation coefficient within the populations, it is illustrated that the genetic distance between O. japonicas and its related plants was far from the strains of O. japonicas, however, the clustering results of wild populations of O. japonicas is similar to that of collection places and morphological characters. Therefore, it can be concluded that it is necessary to make use of wild resources in the process of reproduction, cultivating and breeding... |
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