Wheat Chromosome Scaffold In Situ Induction And Observation

In this thesis, the chromosomes of the root tip meristematic cells of common wheat were treated by histochemistry methods to understand the reality and chemical nature of chromosome scaffold. The shape and structure properties of chromosome scaffolds were observed under the microscope and transmission electron microscope. Again, the existence of actin in chromosomes (chromosome scaffolds) was also studied in situ by immuno-electron microscopy. The results are as follows:1, The slides were prepared according to the routine chromosome preparation technique and were treated by DNase, RNase and NaCl, stained with silver nitrate. It was observated under the microscope and transmission electron microscope that: There is really a scaffold structure exited in common wheat chromosomes; The chemical nature of the scaffold is Non-Histone Proteins (NHPs); Scaffold depicts the whole morphology of the original chromosome; The fine structure of the scaffols is a network structure; The scaffold is also a dynamic structure during the cell cycle; Centromere is part of the chromosome scaffold.2, By using an "en bolc"silver-staining method, the meristematic cells of common wheat were embedded with Epon and the ultrathin sections were examined directly under the transmission electron microscope without uranium and lead staining. The results showed that numerous silver-stained granules, whole size and shape were various, were distributed over the whole sections of chromosomes. If the root tips were treated by low concentration of NaOH before the "en bolc"silver-staining and observated under the TEM, the chromosomes were bleached and there were no silver granules could be seen on chromosome sections. It is certain from these results that the granules in the coromosomes represent the NHPs that constitute into chromosome scaffold.3, The IgG antibody-cooloidal gold immuno electron microscopy technique revealed that gold particles were distributed in the metaphase chromosomes of common wheat. The above resules confirm the existence of actin in the chromosome (chromosome scaffold) of the meristematic cells of common wheat.4, The universal existence and the fine structure and the chemical nature of chromosome scaffold, the relationship between scaffold and helix of chromosome and the existence of actin in the chromosomes were discussed at last.