Chinese Bulletin of Botany ›› 2009, Vol. 44 ›› Issue (06): 682-693.DOI: 10.3969/j.issn.1674-3466.2009.06.005

• 研究报告 • Previous Articles     Next Articles

Ultrastructural Characterization of the Mature Embryo Sac in the Chromosome-9 Monosomic Addition Line of Beta corolliflora in Sugar Beet

Yajia Shang1, Jiaheng Shen1*, Dedong Guo2, Changhong Ding1, Wei Li1, Junping Lu1   

  1. 1Department of Biology, College of Life and Environmental Science, Harbin Normal University, Harbin 150025, China;
    2Department of Biological Engineering, College of Life Science, Heilongjiang University, Harbin 150080, China
  • Received:2008-12-05 Revised:2009-03-20 Online:2009-11-01 Published:2009-11-01
  • Contact: Jiaheng Shen


We investigated by electron microscopy the ultrastructural character of the mature embryo sac in the chromosome-9 monosomic addition line of Beta corolliflora Zoss. in sugar beet, designated M14. The mature embryo sac of M14 consisted of an egg cell, two synergids, a central cell with a secondary nucleus, and 3-6 antipodal cells. The egg cells in different embryo sacs showed different polarity and metabolic activity. They were classified into three types according to the polarity of egg cells: (1) egg cell with regular polarity—the nucleus was located at the chalazal end, and its cytoplasm was rich in organelles such as ribosomes,
mitochondria and endoplasmic reticulum; (2) egg cell with a nucleus at the micropylar end, and (3) egg cell with a centrally located nucleus. The eggs of the third type contained fewer organelles in cytoplasm. The two synergids degenerated before anthesis in most mature embryo sacs. The secondary nucleus, which was close to the antipodals, showed strong metabolic activity. Both the egg cell and the central cell contained large nuclei with distinct nucleoli and numerous organelles. The egg and the central cell were suggested to be active in metabolism, which could be a label of the autonomous division of unfertilized egg cell and central cell in diplospory.