【作者】 贺海洋；

【导师】 高俊平； 上田善弘；

【作者基本信息】 中国农业大学 ， 观赏园艺， 2005， 博士

【摘要】 本研究以稀有植物种类单叶蔷薇为试材,探讨了其在新疆地区的分布状况、生境、物候期、花器官形态建成以及繁殖生物学特性等。 1.单叶蔷薇在我国仅在新疆地区有分布。原生单叶蔷薇的空间分布范围是北纬43°53′94″～46°43′15″,东经83°07′53″～87°33′37″;垂直分布为海拔430-748m。单叶蔷嶶以小居群规模分布在狭小,呈片段化的特殊生境中,分布范围较窄小,土壤和小气候因素对其自然分布起着重要作用。单叶蔷薇物候期分为萌动期、营养枝扩展期、开花期、果实生长发育期、落叶期、休眠期六个主要物候期。对各个时期的形态特征进行了详细描述。对单叶蔷薇适应荒漠干旱地区生长的独特生物学特性和生态适应性进行了分析。 2.单叶蔷薇顶生花芽分化从3月下旬开始至4月下旬完成历时30余天,其过程可分为形态分化前、苞叶分化期、花萼原基分化期、花瓣原基分化期、雄蕊原基分化期、雌蕊原基分化期。其中花瓣原基的分化只进行一次,这是形成单轮花瓣的原因。生殖生长锥在发育过程中可以明显地观察到两层原体细胞,各花器官原基主要来自于花分生组织的边缘区细胞。生殖生长锥直径和细胞数的增长,在生长锥膨大期和心皮分化期较高。 3.单叶蔷薇雌蕊群由20枚左右离生心皮组成,子房单室,内含1枚倒生胚珠,心皮发生类型属于瓶状发生类型,初始心皮向上扩展分化出花柱和柱头,向下延伸嵌入花托发育为下位子房,花柱细长,柱头羽毛状。心皮融合后在有些个体中可以留下明显的腹缝线。心皮败育率为74.3%。这可能是造成单叶蔷薇结籽率较低的原因。 4.单叶蔷薇花药四室,偶见六、七室;花药壁由四层结构组成,最外层为表皮,其内分别为药室内壁、中层和绒粘层,绒粘层原位退化,属腺质型绒毡层,花药壁发育为基本型,小孢子母细胞减数分裂为连续型,四分体排列为左右对称型或四面体型,刚形成的小孢子在形态上存在不同程度的收缩变形。成熟花粉粒为二细胞型。在花粉发育过程中,存在有不同类型的败育现象。 5.单叶蔷薇雌蕊多心皮,一室,胚珠倒生,单珠被,厚珠心,大孢子母细胞减数分裂形成的四个大孢子呈直列式排列。胚囊为单孢发生的蓼形胚囊发育方式。极核在受精前融合为次生核,反足细胞三个,开花后不久退化。开花期间雌配子体具有七细胞八核胚囊和反足细胞退化后的四细胞胚囊。雄蕊先熟,珠孔受精。在胚囊发育过程中,存在着多种不同程度的败育现象。 6.单叶蔷薇胚胎发生类型为茄型。合子在开花后2天就开始第一次分裂。合子分裂通常发生胚乳细胞化之后,随果实发育经棒形胚、球形胚到心形胚阶段,期间胚乳一直包围着胚。在棒形胚到球形胚时胚柄最为发达,到心形胚时胚柄解体。胚乳发育为细胞型。受精后次生核不经过休眠在开花后1日即可观察到初生胚乳核的分裂。具有珠孔端和合点端吸器。 7.单叶蔷薇花两性,单花花期2～3天。在自然状态的居群中,花开放后有昆虫访花。具有一系列适应于虫媒传粉的形态结构和生物学特征,传粉方式为风媒和虫媒,主要以虫媒为主;同时兼有自花与异花授粉的相关机制,异花授粉结实率高于白花授粉,最佳授粉时间为花后24小时。表明单叶蔷薇存在有明显的自交不亲和现象。单叶蔷薇兼有性生殖和无性生殖两种方式。在自然状态下居群数量增长以发达的地下茎行无性繁殖为主。种子几乎没有休眠期无论层积与否种子都很容易发芽。种子中低含量的ABA是影响种子发芽的重要因素,同时种皮结构与发芽存在密切关系。但自然状态下没有发现存在有单叶蔷薇的实生苗。更多还原

【Abstract】 Rosa persica, a rare species of Rosa.L., was investigated on its flower morphogenesis, reproductive biology and distribution in Xin-jiang, China. The results showed that1. The species, Rosa persica is distrituted in only Xin-jiang in China. The distributing region is between 43°53’ 94"~46°43’ 15" N in latitude, 83°07’ 53"~87°33’ 37"E in longitude and 430~748m in altitude. It was found to be endemic to a small area, to occupy a very narrow habitat, to need a strict niche and to appear highly dispersed small populations. Edaphic and community microclimatic factors played a vital role in natural distribution. Rosa persica is a species endemic to Xin-jiang China. Owing to its wild populations are rare, so it is urgent to be protected. The phenophase of Rosa persica was divided into six main stages : sprout stage, vegetative branch stretching stage, blooming stage, fruit development stage, leaf falling stage and resting stage. The appearance characteristic of the each period proceeding was described in details, the biologic characteristics and ecologic adaptability of this kind of special species in the desert and semi-desert was analyzed.2. The flower bud differentiation process lasted for about 30days from bract primordium differentiation in late March to carpel primordium formation in late April. The process could be divided into 6 phases: before differentiation, bract differentiation phase, sepal differentiation phase, petal differentiation phase, stamen differentiation phase and pistil differentiation phase. Of them one time was occurred in differentiation of sepal primordium, and it might be the reason of forming the simple layer of sepal. An larges of each floral primordium originated in peripheral zone cells of floral meristem . The increase of cell number and diameter of apical point was higher in both extension phase and carpel differentiation phase.3. The gynoecium have composed of about 20-free carpels, the ovary is 1-loculed and 1-anatropous ovule. The carpel initiation belongs to the ascidiate type. Styles and stigmas are differentiated as the incipient carpels extend upward, while the inferior ovary is formed by incipient carpels inserting into receptacle, long style and plumate stigma. The degeneration of pistil was observed , and the abortion rate of carpel was about 74.3%. This was considered as a factor responsible for the low seed set in Rosa persica.4. The anther was four-sporangiate, accidentally seen six or seven-sporangiate. The development of anther walls conforms to the basic type, and its wall was composed of four layers: epidermis, fibrous endothelium, middle layer and tapetum respectively, and the tapetum is secretory type. The development of the tapetum with 2-nucleate cells is of the glandular type. Cytokinesis of microspore mother cell in meiosis was successive type and the microspore tetrads were tetrahedral or isobilateral. Tetrad cells and microspores are irregularly shaped during the microsporogensis. The mature pollen grains were 2-celled. During the development process male gametophytes were differently abnormal in stame.5. The gynaecium were polygynous, and the ovule were anatropous, unitegmic and crassinucellate. The megaspore mother cells undergo meiotic divisions and develop into a linear tetradas of megaspores. The chalazal megaspore are functional one, which develops into a polygonum type of embryo sac. The two polar nuclei fused into a secondary nucleus before fertilization. On the blossom day, female gametophyteswere mainly 7-celled with 8-nucleus or 4-celled with antipodal cells degenerated. Three antipodal cells was degenerated. Flowers was protandrous , and porogany . During the development process of female gametophytes were many differently abnormal in embryo sac.6. The embryo development was of the solanaceous type. In two days after pollination zygote begins dividing. And the first division of the zygote took place after the cellularization of endosperm free nuclei. After the club-shaped and the globular embryo period, the heart-shaped embryo develop更多还原