| Populus hopeiensis huet Chow is the plant of Populus Sect.Leuce and Sect.Trepidae Dode.It's a tall trees, is a domestic species in Central section and Northwest China,and it is one of the most important indigenous tree species used for the production of soil and water conservation forest and windbreak forest and greening of barren hills,and is particularly in soil erosion of middle of the Yellow River.In this paper, the allozymic variation of six populations of Populus hopeiensis Gansu was analyzed and themselves genetic variation was discussed on protein level by allozyme analysis.The purpose of the study is to provide a theory basis for studying origin and ecological adaptation of populations.Meanwhile, Populus hopeiensis's rapid propagation system was optimized by studying the tissue culture.It can provide the reference for its reserving method and rapid propagation and take this excellent variety popularized fast into application and insemination. The results showed as follows:(1) According to Rf analysis of PER, EST, MDH, AAT, ADH, IDH, FDH, LDH allozymes,the Rf of six populations are basic identical at twenty-six bands.Although among the Rf being some differences, the average difference was only 0.01. This showed populations will produce different ecological adaptation in different site conditions.But it can not account for existing the genetic differences. Populus hopeiensis of Gansu is a clone of highly pure.(2) According to analysis of PER, EST, MDH, AAT, ADH, IDH, FDH, LDH allozymes of six populations, twenty-six alleles were analyzed in twenty-six loci.All loci were monomorphic loci. Allele frequencies of every loci were 1.0. Genetic variation of six populations were not exist,and genetic differentiation between six populations were not also exist,and genetic distance between populations were zero, there was not relationship between genetic distance and geographic distanceamong populations.Six populations had the same genetic basis and theorigin, from identical clone.On the base of predecessor,father demonstrated its origin question,and reasonable deduced that Populus hopeiensis of Gansu were spreaded from Wuqi Shanxi toGansu by the human factor,and were spreaded from east to west after many years,and formed today's distribution. (3) The tissue culture rapid propagation system of Populus hopeiensis was optimized, the result showed that the best initial medium is 1/2MS+6-BA0.5mg/L+ NAA0.1mg/L,and the start-up rate was 81.87% after thirty days, the best proliferation medium is 1/2MS +6-BA0.5mg/L+ NAA0.05mg/L, and the proliferation modulus was 4.15 after sixty days,and the rooting medium is1/2MS +IBA 0.2 mg/L,and the rooting rate was 90%。... |
