摘要
兰花蕉种子球形或近球形，具表皮毛，种脊不明显。种子包括假种皮、种皮、外胚乳、内胚乳和胚五部分。假种皮具３～４条粗毛状裂片，包围种子或不定向伸展；裂片最外方为１层表皮细胞和１～３层厚壁细胞，内方为薄壁细胞；表皮细胞和厚壁细胞的壁增厚并木质化；成熟时裂片下部１／２段中空。种皮由外珠被发育而来，但内珠被在种子发育后期才萎缩。种皮分化为外种皮，中种皮与内种皮；外种皮由１层表皮细胞构成，其细胞壁增厚并木质化；中种皮外方为２～３层厚壁细胞，内方由１２～１５层薄壁细胞构成；内种皮由１层径向延长的石细胞构成，其细胞壁网状增厚，胞腔不明显。外胚乳极不显眼，大部分只由１层切向延长的长方形细胞构成，局部为２～１７层细胞；外胚乳细胞主要含许多脂类物质及少量蛋白质颗粒，不含淀粉。内胚乳占据种子很大的体积，由通常径向延长的长方形、长条形或方形薄壁细胞构成；细胞内充满淀粉粒和通常一颗亦有２至多颗菱形或方形蛋白质晶体，脂类物质极少。胚圆柱形，胚根和胚芽不明显。种子珠孔区不分化出珠孔领和孔盖，但具柄，柄的远轴端边缘大部分着生假种皮，着生假种皮一侧柄略膨大。合点区内种皮出现极宽的缺口，缺口间为整体呈弧状长条形的合点区厚壁细胞群。较粗的种脊维管?
The seed of Orchidantha chinensis T. L. Wu, with spheroidal or nearly spheroidal shape, having epidermal hairs and an unclear raphe in surface view, comprises aril, seed coat, perisperm, endosperm and embryo. Aril consists of 3～4 coarse hair-like lobes and encloses the seed or extends in different direction. The outer most part of aril lobes is 1 layer of epidermal cells followed by 1～3 layers of sclerenchyma cells. Cells of these two kinds are with thickened and lignified cell wall, while the rest part of them comprises parenchyma cells. The lower half part of aril lobes is hollow at mature stage. Seed coat differentiated into exotesta, mesotesta and endotesta, is developed from outer integument. Inner integument is not shrivelled untill the late stage of the seed development. Exotesta is composed of one layer of epidermal cells with thickened and lignified cell wall. The outer part of mesotesta consists of 2～3 layers of sclerenchyma cells and the inner part contains 12～15 layers of parenchyma cells. Endotesta includes 1 layer of radially elongated sclereids with reticularly thickened wall and obscure lumen. Perisperm is not easy to be observed because major part of it consists of only 1 layer of parenchyma cells which are tangentially elongated. It is merely a few parts of it with 2～17 layers of parenchyma cells. Cells of perisperm contain mainly lipids, a small amount of protein granulars but no starch grain. Endosperm occupies large volume of a seed and consists of many layers of parenchyma cells which are radially elongated, with oblong, linear or square shape. These cells are filled with starch grains as well as mostly one and sometimes 2 to many rhomboidal or square shaped protein crystalloids, but lipid is seldom seen. Embryo is cylindrical shape and radicle and plumule haven′t been differentiated. Micropylar collar and operculum are absent but a stalk is differentiated in micropylar region. Aril is borne on major part of margin of the distal end on a stalk, where the stalk slightly swells. However, on another side, the small part of margin lacks aril. A very wide gap of endotesta occurs in chalazal region and is filled with chalazal sclerenchyma cell group, of which the outline is arching and linear-shaped. In chalazal region, raphe vascular bundle branches into 10 or 8 bundles, which extend toward micropylar region, so the type of vascular supply of seeds belongs to many postchalazal bundles.
出处
《广西植物》
CAS
CSCD
北大核心
1997年第3期235-241,共7页
Guihaia
基金
国家自然科学基金
关键词
兰花蕉
种子
解剖学
组织化学
Orchidantha chinensis T. L. Wu
seed
anatomy
histochemistry
