Plant Diversity ›› 2010, Vol. 32 ›› Issue (6): 495-502.DOI: 10.3724/SP.J.1143.2010.10139

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Ultracytochemical Localization of Calcium during Embryo Sac Development in Phaius tankervilliae(Orchidaceae)

 LI  Dong-Mei-1,3, WANG  Y-Qin-2, YIE  Xiu-Lin-3     

  1. 1 Shunde Polytechnic, Foshan 528300, China; 2 College of Life Science, South China
    Normal University, Guangzhou 510631, China; 3 South China Botanical Garden,
    Chinese Academy of Sciences, Guangzhou 510650, China
  • Received:2010-07-29 Online:2010-12-25 Published:2010-10-09
  • Supported by:

    Plan Project sponsored by the Department of Science and Technology of Guangdong Province (2009B020405002)


 Ultracytochemical localization of calcium in embryo sac of Phaius tankervilliae(Aiton) Bl. was carried out using potassium pyroantimonate precipitation method. Results of Ca2+ distribution during embryo sac development are as following: (1) Megasporocyte stage: There is no Ca2+ precipitation in the megasporocyte, nucellar cell and micropyle; (2) Functional megaspore stage: Small particles of Ca2+ precipitates appear on the embryo sac wall at the micropylar end, but no apparent Ca2+ can be found in the functional megaspore; (3) 4nucleate stage: There are significant increase of Ca2+ precipitation on the embryo sac wall and large grains of  the precipitates in the micropyle, while a little starts to appear on the membrane of vacuole; (4) 8nucleate embryo sac stage: Ca2+ precipitation continuously increases on the embryo sac wall. Distribution of Ca2+ in embryo sac shows strong polarity. More Ca2+ precipitations are observed in the synergids and the egg cell than the antipodal cells. Accumulation of Ca2+ precipitation is achieved by (1) transferring Ca2+ to embryo sac through the plasmodesmata between the nucellar cells, which mainly occurred at the chalaza end before the embryo matured; (2) forming large amounts of small bubbles of Ca2+ precipitation, which can cross embryo sac wall to enter embryo sac.

Key words: Phaius tankervilliae, Embryo sac, Ultracytochemistry, Potassium antimonite technique, Ca2+

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