| Most of natural Liriodendron populations were felled in history, some gene resources had been lost. In order to conserve the remainders scientifically and utilize rationally, it was necessary to make clear genetic diversity and population differentiation within the species.This study could provide the theoretical references and basic data for the gene resources conservation and genetic improvenment in this species by ISSR.The major conclusions were described as fellows:1. Some influencing factors on ISSR-PCR analysis, such as Mg2+ dNTPs, Taq DNA polymerase, temp late DNA and primer, were selected and optimized, using Liriodendron as materials. The optimal ISSR-PCR reaction system for Liriodendron was determined as follows:30ng template DNA, o.3μmol·L-1 primer,0.2 mmol·L-1 dNTPs, 1.4 mmol·L-1 Mg2+,0.4 U Taq DNA polymerase in a total volume of 20μL, and the amplification condition was 5min at 94℃,45×1min at 94℃,45s at 50℃-56℃,2min at 72℃,7min at 72℃.2. The genetic diversity of 200 individuals of 20 Liriodendron natural popolation was estimated using ISSR makers. The eight primers employed a total of 70 scorable amplified fragments, of which 43(61.43%) were polymorphic. Genetic diversity analysis showed that Nei's genetic diversity (H) was0.1717 and shannon's genetic information index (I) was 0.2722. The genetic diversity level of 20 popolations was little. The percentage of polymorphic loci of twenty populations changed from 49.87% to 79.32%, and Nei's genetic diversity (H) and shannon's genetic information index (I) changed between 0.1263-0.1876 and 0.1915-0.2987. Goeffcient of genetic differentiation (Gst) among twenty populations was 0.6173, indicating that natural population was genetically differentiated to a certain extent. 3. The result of cluster analysis by Nei's genetic distance is that the five populations of the Liriodendron tulipifera is one group; the L. chinense could have been divided into three important parts as southern, northern and the centre in china. |
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