沙冬青成熟胚囊助细胞的超微结构观察

本文对沙冬青（Ａｍｍｏｐｉｐｔａｎｔｈｕｓｍｏｎｇｏｌｉｃｕｓ）成熟胚囊助细胞的超微结构进行了观察，结果如下：１）开花前一天助细胞珠孔端有明显的丝状器，并在其附近的细胞质中有许多管状内质网，核位于珠孔端，细胞器主要集中在核周围和合点端细胞质中，两助细胞超微结构一致。２）开花当天，助细胞合点端细胞壁消失，近珠柄侧的助细胞中细胞器变得稀少，内质网膜和质体膜变得模糊不清，而远珠柄例的助细胞中细胞器发达，此时，两助细胞在超微结构上显示出明显的差异，表明与其功能、退化和花粉管进入有关。

Ultrastructural Observations on the Synergid of the Mature Embryo Sac in Ammopiptanthus mongolicus

he ultrastructure of the synergid of the mature embryo sac in Ammopiptanthus mongolicuswas investigated. At the micropylar end of the synergid an elaborate filiform apparatus is distinctone day before anthesis , and many ER tubules are dispersed in the cytoplasm of the micropylarend. The nucleus is located in the micropylar end and its nucleolus is larger. The majority of or-ganelles, are distributed at the chalazal part and around the nucleus,and especially there are abun-dant ER. At the chalazal end the intact wall exists between the synergid and the central cell.Thedifference of the two synergids is unremarkable before anthesis ,but obvious in the anthesis. Whenanthesis ,the synergid near funicle has few ER and other organelles , displaying the indication ofthe generation, but the synergid far from the funicle contains numerous rough ER ,dictyosomesand some plastids in the cytoplasm. The difference of the ultrastructure of the two synergids is re-lated with the entrance of pollen tube and the function and degeneration of the synergid.