葎草的胚后发育

本文应用光学显微镜对葎草的胚后发育进行了研究。核型胚乳,具合点吸器。胚柄二细胞,在心型胚时期退化。合子第一次分裂为横裂,胚胎发育为柳叶菜型。成熟胚胎呈盘旋状态,子叶细胞内含有大量的油脂颗粒。种皮由外珠被发育而成,其外表皮细胞内含有乳汁。果皮内表皮细胞径向延伸呈栅栏状,细胞壁厚呈波纹状,起着机械支持和保护种子的作用。

The Metaembryonic Development of Humulus Scandens(Lour.)Merr.

This paper deals with the development of the embryo,endosperm, seed coat and pericarp of Humulus scandens(Lour.)Merr.with the light microscope. The endosperm is nuclear.The chalazal region remains multinu- cleate and in haustorial.Only the degenerated remnants of endosperm persist in the mature seed.The first division of zygote is transverse. The basal cell cb forms a 2-celled suspensor that degenerates at the heart shaped embryo stage.The derivatives of the terminal cell ca produce the embryo.The mature embryo is dicotyledonous and bears two well developed plumular leaves,each of that contains many grains of oil. The entire inner integument is used up before maturity of the seed. The outer epidermis of the outer integument has latex-filled cells.The mature seed has a rudimentary seed coat.The pericarp is thick,hard and encloses a single seed.The inner epidermis consists of elongated palisade-like cells which later develop heavy lamellations on their walls with supporting and protecting action on the seed.