Ingrowths at the micropylar end of embryo sac from late stage of 1-nucleate to cellularization enlarge the surface of membrane greatly so as to enhance non-symplastic transportation.

• 在单核胚囊发育后期至细胞化胚囊，是通过珠孔端所形成的壁内突来扩展质膜表面积, 以加强非共质体之间物质的运输。