【作者】 龙华；

【导师】 李鹄鸣；

【作者基本信息】 吉首大学 ， 生态学， 2008， 硕士

【摘要】 獐牙菜及湖北双蝴蝶均为龙胆科植物,在湖南湘西地区自然分布区和生境极为相似,但进化方向和利用资源方式却截然相反。对这两种植物进行生态解剖学和比较胚胎学研究,对于深入了解植物的系统和演化、物种形成、适应起源以及物种的保护生物学等具有一定的理论和实际意义。同时,獐牙菜和湖北双蝴蝶为我国的传统中药,药用价值较高,但目前正遭受着严重的胁迫,而迄今从生态解剖学、胚胎学等基础生物学的角度对它们的研究尚为空白。因此,通过本研究,可进一步丰富完善獐牙菜属及双蝴蝶属植物的基础理论资料,为我国传统药用植物保护、开发及持续利用服务。1.生态解剖学研究植物体的每一部分都是相互协调而共同完成某一生理功能。研究表明不同生境獐牙菜及湖北双蝴蝶茎、叶的解剖结构发生了适应生态环境的变化。其中,叶片的变化最为快速明显,在光照较强的生境中,主要表现为叶片厚度增厚,以增强植物的保水能力;栅海比增高,以提高光合效能及反射强光的照射;叶片气孔密度增大,以加大呼吸面积。不仅叶片的解剖结构会发生变化,茎的解剖结构也会发生相应的改变,茎皮层增厚以减少水分的蒸发和提高光合效能;而发达的髓部有利于植株保水和贮水能力。总之,在光照较强的生境中,植株一方面是减少水分的丧失控制蒸腾,另一方面是提高本身的光合效能。2.胚胎学对獐牙菜和湖北双蝴蝶的胚胎学进行了深入、全面的研究。主要结果如下:獐牙菜:花药四室,药壁发育为基本型;绒毡层异型起源,属于腺质型绒毡层,药室内具有的退化绒毡层核是早期该层细胞有丝分裂凸入药室中央并原位退化形成的;中层细胞2层;药室内壁同表皮同时宿存,细胞柱状伸长,纤维状加厚。小孢子母细胞减数分裂为同时型,四分体排列方式主要为四面体形,少数为左右对称形和十字交叉形;成熟花粉为2-细胞类型。子房2心皮,1室;侧膜胎座,薄珠心,单珠被,倒弯生胚珠;大孢子母细胞减数分裂形成4个大孢子直线形排列,合点端的大孢子具功能,胚囊发育为蓼型。3个反足细胞宿存,每个细胞均多核和异常膨大,反足细胞的吸器明显,并在胚乳之外形成染色较深的类似“外胚乳”的结构。珠孔受精,受精作用属于有丝分裂前类型。胚乳发育为核型;胚胎发育为茄型。果实成熟时,种子发育至球形胚阶段。反足细胞在龙胆科一些短命植物中的宿存与分裂具有重要的生殖适应与进化意义。同时,根据现有的资料,对獐牙菜属的几种植物进行了比较胚胎学研究。湖北双蝴蝶:花药四室;药壁发育为双子叶型;绒毡层属异型起源,细胞具单核,属腺质型绒毡层,药隔处的绒毡层细胞形成类胎座,其余部位的绒毡层细胞仍为一层细胞;在花药成熟时,花药的药室内壁纤维状加厚且柱状伸长,表皮细胞减缩退化,纤维状加厚不明显。小孢子母细胞减数分裂为同时型,四分体排列方式主要为四面体形,少数为十字交叉形;成熟花粉为2-细胞型。子房为2心皮;1室,侧膜胎座,薄珠心,单珠被,倒生胚珠;胚珠为4列;大孢子母细胞减数分裂形成的4个大孢子呈直线式排列,合点端的大孢子具功能;胚囊发育为蓼型;珠孔受精;胚乳发育为核型;胚发育为茄型。果实成熟时,种子发育至球形胚阶段。同时,根据现有的资料,对双蝴蝶属的几种植物进行了比较胚胎学研究。3.组织培养研究针对獐牙菜及湖北双蝴蝶野生资源受到严重破坏的情况,本文系统地探讨了通过组织培养为手段进行人工繁殖的方法獐牙菜的组织培养研究结果如下:将种子接种于诱导培养基上,待其长成小苗后分别取其不带芽茎段、叶和带芽茎段作为外植体,在MS培养基上添加不同的激素配比,改变培养方式。在所有的实验方案中,不带芽茎段是理想的外植体材料。较适宜的初代培养基为MS+BA0.5mg/L +蔗糖3.0%,增殖培养基为MS+BA0.5mg/L+ IBA0.1mg/L +蔗糖3.0%,而根的诱导则是在1/2MS+ NAA0.5mg/L + 1.5%蔗糖的培养基上进行。湖北双蝴蝶的组织培养研究结果如下:以湖北双蝴蝶带芽茎段、不带芽茎段及叶片为外植体,以MS为基本培养基,通过添加不同的激素配比,建立湖北双蝴蝶组培快繁体系。在所有实验方案中,带芽茎段的出愈率最高,是理想的离体快繁材料。较适宜的初代培养基为MS+BA2.0mg/L+蔗糖3.0%,增殖培养基为MS+BA2.0mg/L+NAA0.1mg/L+蔗糖3.0%,而根的诱导则在1/2MS+NAA0.5mg/L+蔗糖1.5%的培养基上进行较为适宜。更多还原

【Abstract】 Swertia bimaculata ( Sieb.et Zucc. ) Hook.f.et Thoms.ex C.B.Clarke and Tripterospermum discoideum(Marq.)H.Smith are belong to Gentianaceae. Although their distributing areas and habitat are similar, their evolutionary trends and the way to utilize resource are poles apart in the area of Western Hunan. Ecological anatomy and comparative embryology of these two plants were studied which has definite theoretical and practical significance in understanding plant system and evolvement, the speciation, the adaptation origin, the conservation biology and so on. At the same time, as valuable Chinese traditional medicines, both of them are subject to serious intimidation. Up to now, the basic biological researches on ecological anatomy and comparative embryology of them are still blank. So this research can further enrich the base theoretical information about Swertia and Tripterospermum, and serve the protection, development and sustainable utilization of our traditional medical plants.1. Ecological AnatomyEach part of plant is mutual co-ordination to accomplish a certain physiological function. The results showed that S. bimaculata and T. discoideum in different habitats changed their anatomical structures of stem and blade to adjust the ecological environment. The changing of blade structure was the fastest and most evidential. In strong sunlight, the thickness of blade has increased to improve water retention ability; the ratio of palisade tissue and spongy tissue rose to improve the photosynthetic efficiency and reflect the strong light; the density of epidermal stoma also increased to enlarge the respiratory area. Not only did the structure of blade changed, but also the stem changed correspondingly, such as the thickness of cortex increased in strong sunlight so that the cortex can reduce evaporation and improve the photosynthetic efficiency. The well-developed pith is benefit for plants to keep and store water. In conclusion, the plants which live in strong sunlight, for one thing control the evaporation to reduce water loss, for another improve the photosynthetic efficiency.2. EmbryologyThe studies include the development of microsporangium, male gametophy, megasporogenesis, female gametophyte and embryogeny of S. bimaculata and T. discoideum.The main results of S. bimaculata can be concluded as follows: Anthers are tetrasporangiate. The development of anther walls conforms to the basic type and comprises of epidermis, endothecium, two middle layers and tapetum at the mature stage. The tapetum cells have dual origin and belong to the glandular type, for the anther locules have degenerating tapetum nuclei in the middle which are from the early dividing and intruding of the tapetum. Two middle layers are ephemeral; endothecium and epidermis persists and develops to become fibrous-thickening. The cytokinesis of the microspore mother cell in meiosis is of the simultaneous type. Most of the microspore tetrads are tetrahedral and there are still a few other types, such as isobilateral, dilateral . Pollen grains are 2-celled when shed. The ovary is bicarpellate, unilocular with 4 rows of ovules located at the parietal placentation. The ovule is unitegmic, enuinucellar and ana-campylotropous. The embryo sac originates from the single-archesporial cell. The one chalazal megaspore in linear tetrad becomes the functional megaspore. The development of embryo sac is the Polygonum type.Three antipodal cells have multiseriate nuclei and distinct haustorium, and persist like a layer of“outer endosperm”just out of the endosperm nucleus layer. Fertilization is porogamous and of premitotic syngamy type. The development of endosperm conforms to Nuclear type and the embryogeny corresponds to the Solanum type. The embryo is at the globular stage when seeds released from the capsule. The dividing and persisting of the antipodal cells in some annual Gentianaceous plants are of significance in reproductive adaptation and evolution. At the same time, comparative embryology among some species of Swertia was studied base on some recent data.This paper reports embryological characters of T. discoideum. The main results can be concluded as follows: Anthers are tetrasporangiate. The development of anther walls conforms to the Dicotyledonous type. The tapetal cells origin from the primary parietal cells, and thus the tapetum is of dual origin. The development of the tapetum with uninucleate cells is of the Glandular type. The tapetal cells on the connective side show radial elongation or periclinal division and intrude into the anther locule to form placenoids. The anther wall has only one middle layer; the endothecium persists and its cells become pillar and fibrous, and the epidermis degenerates. Cytokinesis at meiosis of microsporocytes is of the simultaneous type and most of microspore tetrads are tetrahedral, there are still a few other types, such as dilateral. Pollen grains are 2-celled. The ovary is bicarpellary and unilocular. The placentation is of reduced or typical parietal placentae with 4 rows of anatropus ovules that is unitegmic and enuinucellar. The one chalazal megaspore in linear tetrad becomes functional. The development of embryo sac is of the Polygonum type. Three antipodal cells persist. Flowers are protandrous. Fertilization is porogamous. The development of the endosperm is of the Nuclear type. The embryogeny corresponds to the Solanad type. The embryo is at the globular stage when seeds released from the capsule. At the same time, comparative embryology among some species of Tripterospermum was studied base on some recent data.3. Tissue cultureIn order to protect the natural resources of S. bimaculata and T.discoideum, which has been destroyed seriously, the method of artificial propagation by way of tissue culture have been systematically researched.The results of S. bimaculata: When the seeds that were on the initial phytohormone before grow into seedling, then take the stems, leaves and the stems with buds from seedling as explants, which are cultured on different culture media with the addition of different portions of various hormones at various cultural conditions. The stems were the best material in speeding propagation among the three explants (stems with buds, stems and leaves). The proper medium for the shoot differentiation was MS+ BA0.5mg/L + saccharose 3.0%, the optimum medium for proliferation was MS+BA 0.5mg/L+ IBA0.1mg/L+ saccharose 3.0%,and the best medium for rooting was 1/2MS+ NAA 0.5mg/L + saccharose 1.5%.The results of T. discoideum: The tissue culture and rapid proliferation techniques of T. discoideum were studied by using stems with buds, stems without buds and leaves as explants. The explants were cultivated in different MS medium with different types and concentrations of plant growth substances. The main results can be concluded as follows: the stems with buds were the best material in speeding propagation among the three explants. The shoot differentiation was MS+BA2.0mg/L+saccharose3.0%, the optimum medium for proliferation was MS+BA2.0mg/L+NAA0.1mg/L+ saccharose 3.0%,and best medium for rooting was 1/2MS+NAA0.5mg/L+saccharose1.5%.更多还原