扁豆成熟胚囊的超微结构

本文对扁豆（Dolichos lablab)成熟胚囊的超微结构进行了研究，在成熟胚囊中，卵细胞和助细胞仅在珠孔端1／3有细胞壁，靠近合点端，卵细胞一助细胞，卵细胞－中央细胞，助细胞－中央细胞之间没有细胞壁存在，相邻细胞的质膜靠在一起，在卵细胞和中央细胞的质膜间，有些地方存在中等电子密度的物质，卵细胞的细胞质中含有很多的线粒体和质体，内质网和高尔基体较少，助细胞的珠孔端有一复杂的丝状器，靠近珠孔端的细胞质中有很多管状的内质网，表明助细胞可能具有分泌功能，在助细胞的合点端，含有丰富的粗糙内质网，助细胞和卵细胞的质膜之间有很多囊泡状的结构，中央细胞内含有丰富的线粒体，高尔基体和内质网，中央细胞的壁向内形成突起，在周缘细胞质中含有丰富的脂滴。

THE ULTRASTRUCTURE OF MATURE EMBRYO SAC IN DOLICHOS LABLAB

The ultrastructure of the egg and the central cell in Dolichos lablab was investigated. When the embryo sac is mature,cell wall is formed only at the micropylar end of the egg and the synergids.At the chalazal end,no cell wall exists between the egg and the synergid,bet- ween the egg and the central coll,between the synergid and the central cell,and the plasma membranes of the adjacent cells are very close to each other.In some regions between the plasma membrane of the egg and that of the central cell,some moderate electron dense substa- nces are present.Many mitochondria and plastids are present in the egg cytoplasm,but ER and dictyosomes are few.At the micropylar end of the synergid an elaborate filiform appara- tus is distinct,and many ER tubules are dispersed in the cytoplasm of the micropylar end.It shows that the synergid would have a secretory function.The synergid contains numerous rough ER in the cytoplasm at the chalazal end,and between the plasma membrane of the egg and that of the synergid there are some vesiculae,indicating active metabolite transport betwe- en two cells.The central cell displays a high metabolic activity since numerous mitochon- dria,dictyosomes and ER are present in its cytoplasm.Its cell wall ingrowths form a lot of finger-like projections penetrating into the cytoplasm,which displays the feature of the transfer cell.There are many lipid bodies in the peripheral,cytoplasm.It is suggested that the central cell would play an important role in the nutrition of the embryo sac.