【作者】 董美芳；

【导师】 尚富德；

【作者基本信息】 河南大学 ， 遗传学， 2005， 硕士

【摘要】 本文利用外部观察、测量和常规石蜡切片法,在显微水平上,系统地研究了小盐芥(Thellungiella halophila (C. A. Mey.) O. E. Schulz )的各营养器官的解剖结构,探讨了其可耐高盐环境的结构基础;首次报道了小盐芥的小孢子发生及雄配子体发育过程、大孢子发生及雌配子体发育过程、受精过程、胚及胚乳发育过程,以及上述各过程不同阶段与花蕾、花、果实外部形态的相关性。结果如下: 1.小盐芥根、茎、叶的解剖结构特点与干旱盐渍环境相适应,其盐生类型更倾向于假盐生植物。(1)根为二原型,初生结构中表皮细胞一层,皮层仅由外皮层和内皮层两层细胞构成。三层细胞大而高度液泡化。次生维管组织发达。(2)茎的初生结构中外韧维管束 8~10 束,大小不等,呈一轮排列;髓和髓射线发达。茎次生结构中维管组织也很发达。(3)叶片较小,上、下表皮细胞各一层,细胞大而高度液泡化,叶肉中栅栏组织与海绵组织分化不明显。小盐芥上述特征与典型真盐生植物、旱生植物相去甚远。盐处理前后其营养器官内部结构无明显变化,也无盐腺、囊泡等泌盐结构。由此推论,小盐芥更倾向于假盐生植物。 2.小盐芥雄蕊为四强雄蕊,每个花药具 4 个花粉囊。小孢子母细胞减数分裂属同时型,小孢子在四分体中的排列方式属四面体型。成熟花粉粒属 3-细胞型,有 3个萌发沟。花粉囊壁发育属双子叶型,由 4 层细胞构成:表皮、药室内壁、中层和绒毡层。绒毡层为腺质绒毡层。 3.小盐芥雌蕊由 2 心皮组成,侧膜胎座,每室胚珠多数,弯生,双珠被,薄珠心。孢原细胞位于珠心表皮之下,直接起大孢子母细胞的功能。大孢子四分体线形排列,合点端大孢子为功能大孢子,胚囊发育为蓼型。受精前,2 个极核融合成次生核。受精作用属有丝分裂前型。胚乳发育为核型。胚发育属柳叶菜型,子叶背倚胚根。成熟种子无胚乳。 4. 植株形成肉眼可见花蕾时,雄性孢原细胞开始分化。雄性生殖器官发育较雌性为早,但在花蕾露白时雄配子体和绝大多数雌配子体均已发育成熟,为自花传粉创造了条件。花盛开前后,是受精作用的核融合时期。以后,随着胚的发育,子房迅速伸长。更多还原

【Abstract】 This experiment studied the anatomy and embryology of halophyte, Thellungiella halophila (C. A. Mey.) O. E. Schulz, through outside observation, measure and light microscopy of paraffin-sectioned material. The article details systematically the relationships between the anatomical structure of vegetative organs of Thellungiella halophila and its high salinity tolerance. The research included its microsporogenesis, the development of male gametophyte, megasporogenesis, the development of female gametophyte, fertilization, the development of embryo. Furthermore, the experiment studied the relationships between different stages of the processes sited above and morphological character of flower bud, flower and fruit. Conclusions as follows: 1. the structural characters of root, stem and leaf are adapted to drought and salinated environment. And its halophytic type is more likely to that of pseudohalophyte. (1) Primary structure in its roots has one layer of large, vacuolated epidermis cells. Internally, cortex is comprised of exodermis and endodermis whose cells are similar to that of epidermis in structural feature. (2) primary structure in its stem includes a ring of 8~10 different vascular bundles in size, pith and rays. There are developed vascular tissues in secondary strucrure of roots and stems. (3)Its leaf includes seperately one layer of upper and lower epidermis cells with large and highly vacuolated cells. Between the epidermises lies the indistinctly differentiated mesophyll with many big chloroplasts, surrounded by many spaces. The features commened above is adapted to drought, salination soil. The paper concludes that Thellungiella halophila is more likely to pseudohalophyte for it has no typical nature of euhalophyte or secretory structure such as salt glands before or after salt adaptation. 2. The androecium of Thellungiella halophila are tetradynamous stamen. Each anther has four pollen sac. The cytokinesis of microspore mother cell during meiosis is of simultaneaous type. Its tetrasporophyte is tetrahedral. The mature pollen grain (male gametophyte) is of 3-cell, and each has 3 germinal aperture. The development of anther wall follows the dicotyledonous type, composed of four layers, respectively epidermis, endothecium, middle layer and tapetum. Its tapetum is named as secretory tapetum. 3.The ovary is comprised of two carpels where forms parietal placentation on which many campylotropous ovules grow. The ovule is bitegminous and tenuinucellate. The archesporial cell lies under nucellus epidermis, which developes into functional megasporocyte. Megaspore tetrad is linear. The chalazal megaspore develops into an embryo sac of Polygonum type. The polar nuclei fuse before fertilization. Double fertilization is of the type of Premitotic syngamy. Endosperm formation belongs to nuclear type. Embryogeny conforms to the Onagrad type (Crucifer type) and cotyledons lean against radicle back-to-back. The mature seed has no Endosperm. 4.The archesporial cell diffentiates when the plant generates flower buds observed by naked eyes. The development of male reproductive organ is earlier than that of female. But male and female gametophytes have become mature before flower bud appears white petals which is the proof we regard Thellungiella halophila as self-pollination plant. The egg nucleus and sperm nucleus fused when flower is in full bloom. Subsequently, the fruit stretchs fast with the development of embryo.更多还原