【作者】 寿海洋；

【导师】 李凤兰； 马清温；

【作者基本信息】 北京林业大学 ， 植物学， 2010， 硕士

【摘要】 土沉香作为我国特有的药用树种,已被列为我国二级重点保护野生植物。本文对土沉香(Aquilaria sinensis (Lour.) Spreng.)的分布状况进行了调查,同时对其生物学特性进行研究,以期为合理地开发和利用这一宝贵植物资源提供必要的生物学依据,也为土沉香的人工种植和育种工作的开展提供必需的生物学依据及科学参考。主要实验结果如下：1、通过腊叶标本及文献资料查询,结合实地调查和电话访问,绘制出土沉香的分布图,结果表明：土沉香在我国自然分布于广东、广西、海南、云南及香港、澳门特别行政区,在台湾、福建、四川金沙江干热河谷等地区有部分的人工栽培。2、通过多种实验方法,分别对土沉香的叶片横切面、气孔分布状况及气孔密度、木材的三个切面、次生木质部导管的类型等普通生物学特性进行了研究,结果表明：(1)土沉香叶片为典型的异面叶,气孔仅分布在下表面,保卫细胞肾形,气孔口长椭圆形；气孔平均长度为22.1±1.4μm,平均宽度为14.3±1.6μm,密度为每平方毫米135±19个。(2)叶片主脉维管束为双韧型并且排列成圆环状,环状木质部与髓之间为较发达的内函韧皮部。(3)木材横切面上可见呈岛屿状分布的内函韧皮部,单列射线占绝大多数；弦切面上可见木射线非叠生,绝大部分为异形Ⅲ型；径向切面上,木射线排列成横向带状,射线细胞长方形。(4)土沉香的次生木质部导管类型多样,多数为细长的管状,少数为较粗、短的形态；有的两端具粗大的尾,有的一端具尾一端无尾,有的两端具残存的尾,有的两端无尾；导管分子均为单穿孔。3、对土沉香小孢子发生和雄配子体发育的过程进行了观察,结果表明：(1)土沉香的小孢子发生和雄配子体发育过程均正常；花药4室,花药壁由4层细胞组成,分别是表皮、药室内壁、中层和绒毡层,绒毡层属于腺质绒毡层,药壁形成方式为双子叶型。(2)小孢子母细胞减数分裂过程中的胞质分裂为同时型,形成的四分孢子大多为四面体型,少数为左右对称型；成熟花粉粒为二细胞型。(3)利用扫描电镜对土沉香的成熟花粉进行了观察,发现成熟花粉呈圆球形,表面为具钝三角形投影的基柱所组成,萌发孔小,边缘不明显,不易被观察到。(4)观察了土沉香的雌蕊结构,发现土沉香为2心皮组成的复雌蕊,2心皮2心室的中轴胎座,每室着生1个直生胚珠,胚珠具2层珠被。更多还原

【Abstract】 Aquilaria sinensis (Lour.) Spreng. is a endemic medicinal tree only found in China, which is listed as China’sⅡprotected wild plants. In this paper, the distribution of A. sinensis (Lour.) Spreng. was investigated, and their biological characteristics were studied with a view of providing necessary biological basis to rationally develop the valuable resources, but also for the artificial cultivation of A. sinensis in the future. This research can also provide essential scientific reference and biological basis for breeding. The main results are as follows:1. The authors drew the distribution map of A. sinensis by consulting herbarium specimens of A. sinensis and related documents, field surveys and telephone interviews, and the result shows that A. sinensis naturally distributes in Guangdong Province, Guangxi Province, Hainan Province, Yunnan Province, Hong Kong and Macao Special Administrative Region of China. There are some of artificial cultivation in Taiwan Province, Fujian Province, Sichuan Province and the Jinsha River valley.2. Numerous methods were used to study the cross-section of leaves, stomatal distribution and stomatal density, the three sections of wood, the types of vessel and other basic biological characteristics, the results showed that:(1)The leaves of A. sinensis are typical bifacial leaf; stomas only distribut on the lower surface of leaf, guard cells are kidney-shaped, stomata’s average length is 22.1±1.4μm, the average width is 14.3μ1.6μm and the density is about 135±19 per square millimeter. (2)The main vein vascular bundle of leaf is two-ductile-type and arranged in circular ring, between the xylem and pith is the more developed included phloem. (3)There are island-like distributed included phloem on the cross-section of the timber with medullary rays mostly separated, xylem rays are non-overlapping on the string-section with mostly belong to type III, and raycells arrange in horizontal band on the radial-section and raycells are rectangular. (4)There are various types of vessel, mostly are fine long tubes, a few are coarse and short form; some ends with thick tails, some vessel have one end non-tail and another end tailed, some with remnanted tails while the others have no taisl at all. Vessel elements are single perforation.3. The authors investigated microsporogenesis and male gametophyte development processes of A. sinensis, the results show that:(1)Microsporogenesis and male gametophyte development processes are normal, the anther has four chambers and the pollen sac wall consists of four layers those are epidermis, endothecium, middle layer and tapetum; the tapetum is of a glandular type, The formation of anther wall shows a dicotyledonous type. (2)Cytokinesis occurs simultaneously with meiosis in a microspore mother cell, and the formed tetrads are mostly tetrahedral while some are symmetrical. The mature pollen grains are of a binuclear type. (3)Using a scanning electronic microscope (SEM) to observe the mature pollen grains, which appeared spherical shape with their surface made up of blunt-triangular projected pillars. The germination pores of the pollen were difficult to observe because of their small size and unclear edges. (4)The structure of pistil is observed, the authors found that A. sinensis is composed of 2 carpets complex pistil,2 carpels 2 ventricular locule, each room with 1 erect ovule, and ovule with two layers of integument.更多还原