Home > Browse Issues > Vol.36 No.11
Ultrastructural Observations of Programmed Cell Death of the Nucellar Cells in Phaius tankervilliae (Aiton) Bl.
Li Dongmei1, He Mengling2, Liang Chengye3, Ye Xiulin3*
1Shunde Polytechnic, Foshan 528300, China;
2School of Traditional Chinese Medicine, Guangdong Pharmaceutical University,
Guangzhou 510006, China;
3South China Botanical Garden, Chinese Academy of Sciences, Guangzhou 510650, China
Abstract: Nucellar cells in Phaius tankervilliae (Aiton) Bl. were observed under transmission electron microscope. Some distinct characteristics were found during the programmed cell death (PCD) of nucellar cells in P. tankervilliae， such as the vacuole splinter， demonstrating the chromatin condensation and cytoplasm disorganization. Many protuberances were present at the megasporocyte cell wall adjacent to the lateral nucellar cells before the formation of the functional megaspore. With the enlargement of the embryo sac， the thickening embryo wall became visible due to the superposition of the vestigial nucellar cell wall. Before maturation of embryo sac， the plasmodesmata connected nucellar cells and embryo sac at the chalazal end. The state of chalazal nucellar cell cytoplasm， especially the morphology of vacuole， was highly similar to that of megasporocyte cell， the functional megaspore and mature embryo sac. The results showed that nucellar cells played important roles in embryo sac development， and PCD of nucellar cells offers space and nutrition to the enlarged embryo. At the same time， the nucellar cell at the chalaza end make a stable interior condition for embryo sac development.
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