Molecular Cytogenetic Study On Chinese Fir (Cunninghamia Lanceolata)

Molecular Cytogenetics is the development direction of the modern cytogenetics. Chinese fir (Cunninghamia lanceolata ), one of the local and economically important tree species of China, has been studied in cytology and molecular cytogenetics levels by using fluorescence dyeing, chromosome banding, chromosome microdissection and microcloning and in suit hybridization(ISH). The results will accelerate the theoretical development of the macroscopical cytology and the microscopical molecular cytogenetics of Chinese fir.The mitosis metaphase chromosomes were studied in this paper. The results show that 6 of the 11 chromosomes of Chinese fir were easily identified by C banding, CMA banding is more suitable for the fluorescence banding of Chinese fir than DAPI. Fluorescence banding can be detected in the chromosomes by using CMA, but no banding by DAPI.The meiosis rule of PMC (pollen mother cell) of Chinese fir was studied by consecutively sampling and squashing. The results show that the meiosis phases of PMC of Chinese fir have high correlation with the color transformation of the male flowers. It undergoes a series of changes: filemot, emerald, green, brown, puce. According to the observation of meiosis II telophase tetrad of Chinese fir, the meiosis of tetrad is single plane, the division mode of cytoplast is simultaneous.We firstly reported that there were some abnormal cytology behaviors in the meiosis of PMC(pollen mother cell): univalence,multivalence,chromosome bridges,laggingchromosomes,nonequivalent division , micro-nucleus and etc. The vigor of pollen is commonly low. This phenomenon has correlation with the non-equivalent distribution of germ plasm during meiosis of PMC, which results in the sterility of microspore.We successfully isolated the single chromosome with a satellite of Chinese fir, and amplified the chromosome by using DOP-PCR with a fragment from 100bp to 700bp. The PCR products were ligated to pGEM-T vector(Promega). The quality of the single chromosome library was screened by dot hybridization. The results showed that the proportion of single/low copy was 57.1%, and the mid/high copies was 42.9%.We analyzed the meiosis PMC and mitosis root tips by FISH with ribosome 28S primer. The results showed that the hybridization signals were detected in interphase and prophase during the mitosis of root tip cells and the meiosis of PMC.We firstly analyzed the meiosis PMC and mitosis root tips by GISH with the primers of Japan cedar and Metasequoia genomes, respectively. The results showed that the hybridization signals were detected in most chromosomes by using the primer of Japan cedar genome, but the intensity of each...