Study on the seedless mechanism of seedless‘Hongjiangcheng’

The seedless‘ Hongjiangcheng’〔Citrus sinensis（L.）Osbeck〕and seedy‘ Hongjiangcheng’were used as materials of the experiment in the study. Their pollen viability and germinating viability，embryo sac fertility and embryonic development were studied. The results showed that，compared with the seedy‘ Hongjiangcheng’，the pollen sterility of seedless‘ Hongjiangcheng’ happened，the pollen viability and germinating viability significantly declined and rate of malformation significantly rised at the same time. The pollen viability and germinating viability of seedless‘ Hongjiangcheng’belonged to the type of low development. The embryo sac of seedless‘ Hongjiangcheng’ could fertilize normally. Mature embryo sac had one egg，two synergids，three antipodal cells and a big central cell which contained two polar nuclei. The embryonic development of seedless‘ Hongjiangcheng’happened according to the study of a few different periods. The most embryos began to degenerate at the four weeks after pollination. The endosperms disappeared with development and maturity of cells in the six weeks after pollination. And in the seven weeks after pollination，the most embryos and endosperms disappeared and seedless fruits produced in the end. The degeneration of pollen and embryos was the mainly seedless reason for seedless‘ Hongjiangcheng’development compared with seedy‘ Hongjiangcheng’.