云贵地区晚二叠世矿化芦木茎研究

发布时间：2018-03-08 15:20

本文选题：中国西南地区　切入点：晚二叠世　出处：《云南大学》2015年硕士论文　论文类型：学位论文

【摘要】：芦木是晚古生代种类繁盛的大型木贼类植物的总称,是石炭二叠纪最常见的植物化石之一,也是重要的成煤植物。目前欧美植物区芦木类植物的研究已经比较深入和全面,但华夏植物区芦木类植物,特别是芦木茎解剖结构的研究还很少。我国西南地区贵州盘县矿区和云南富源地区晚二叠世地层中产有丰富的、保存完好的芦木茎干化石,为深入了解晚二叠世芦木类植物的形态结构、系统发育与演化提供了重要的化石材料。本论文利用国际上研究矿化植物化石广泛采用的揭膜法和薄片法,对产自云贵地区晚二叠世地层中的大量芦木茎矿化化石进行了详细的研究,主要结果如下：根据大量新发现的标本对已报道的芦木茎筠连节茎木Arthropitys junlianensis进行了深入研究,并对其种征进行了修订,修订后的种征为：植物体为高大乔木,直径可达300mm；茎中央存在一个中空的髓腔,在髓腔边缘具有溶解性空腔；初生射线极快速尖灭,很短,最长达2mm；脊管小而明显,呈卵圆形；在脊管(carinal canal)附近的髓边缘中具有成团分布的黑色分泌细胞；木质部束顶端钝尖,宽约700μm(500gm-1000μm)；2到3圈卵圆形细胞环绕脊管；次生木质部发达,厚可达100mm,由梯纹管胞构成；次生射线窄,由1到2列薄壁细胞组成。描述了一个相似种Arthropitys cf. A. yunnanensis。该种特征为：茎直径超过100mm;茎中央存在一个中空的髓腔,初生射线宽度具有明显收缩,从近髓处开始向外快速变窄,贯穿次生木质部时很细,并有部分没有贯穿次生木质部；脊管明显,呈卵圆形；2到4圈卵圆形细胞环绕脊管；次生木质部发达,每个木质部束顶端呈尖锥型,宽约1000μm-1500μm,由梯纹管胞构成；次生射线细胞在横切面径向长为宽的1-2倍,弦切面为等径的薄壁细胞；具发育的皮层,皮层内有一圈叶痕排列,皮层宽度约5mm,分3层。通过对已发现的我国西南地区晚二叠世3种芦木茎特征的研究,发现3种芦木茎的次生木质部均较发育,说明它们均是较高大的乔木状植物或小树,个体数量较丰富,可能在当时植被中占据优势地位；地理分布范围较广,至少在整个西南地区都有分布；生活环境多样,除生活于岸边或水中外,还有可能生活于高地甚至山坡上；部分标本具有明显的生长轮,表明在该时期该地区气候出现了周期性季节变化,但并不稳定。
[Abstract]:Reed is a general term for the late Paleozoic species of large scale cuttlefish. It is one of the most common plant fossils of the Permian period, and is also an important coal-forming plant. At present, the research on the rosewood species in Europe and the United States has been comparatively thorough and comprehensive. However, there are few studies on the anatomical structure of Reed stem in Huaxia plant area, especially the anatomic structure of Reed stem. In the late Permian strata of Panxian mining area and Fuyuan area of Yunnan Province in southwest China, there are abundant and well-preserved rosewood stem fossils. In order to understand the morphology and structure of the late Permian plants, phylogeny and phylogeny provide important fossil materials. In this paper, the thin-film method and the thin-film method, which are widely used to study mineralized plant fossils, are used in this paper. A large number of mineralized fossils from late Permian strata in Yungui area were studied in detail. The main results are as follows:. According to a large number of newly discovered specimens, the reported Arthropitys junlianensis was studied, and its species sign was revised. The revised species sign was that the plant was tall and tall. The diameter can reach 300 mm, there is a hollow medullary cavity in the center of stem, which has a dissolved cavity at the margin of the medullary cavity, the primary ray is very fast, very short, and the longest is up to 2 mm, the spinal canal is small and obvious, and it is oval. There are black secretory cells in the medullary margin near the spinal canal; the xylem bundles are obtuse at the tip of the xylem bundles, with 2 to 3 circles of oval cells around the spinal canal about 700 渭 m ~ 500gm-1000 渭 m wide; the secondary xylem is well developed, up to 100 mm thick, and is composed of trapezoids; the secondary rays are narrow. Consists of 1 to 2 rows of parenchyma cells. A similar species, Arthropitys cf. A. yunnanensis, is described. The characteristics are: the diameter of the stem is more than 100mm; there is a hollow cavity in the center of the stem, the width of the primary ray is obviously contracted, and the width of the primary ray shrinks rapidly from the near pulp to the outside, and it is very thin when it penetrates through the secondary xylem. Some of them did not penetrate the secondary xylem, the spinal canal was obviously oval, with 2 to 4 circles of oval cells surrounding the spinal canal, the secondary xylem was well developed, each xylem bundle was acicular at the top of each xylem bundle, and its width was about 1000 渭 m to 1500 渭 m, which was made up of trapezoid tracheids. The radial length of the secondary ray cells is 1-2 times as wide as the transverse plane, and the chord section is an equal-diameter parenchyma with a developed cortex, with a ring of leaf marks arranged in the cortex, the width of the cortex is about 5 mm, and the cortex is divided into three layers. Based on the study of the characteristics of the three species of Reed stems in the late Permian in southwest China, it is found that the secondary xylem of the three species are relatively developed, indicating that they are tall Arbor plants or small trees, and the individuals are rich in number. It is possible to occupy a dominant position in the vegetation at that time; the geographical distribution is relatively wide, at least in the whole southwest region, the living environment is diverse, in addition to living on the shore or in the water, it is possible to live on the high ground or even on the hillside; Some of the specimens had obvious growth rings which indicated that the climate of the region had periodic seasonal changes but was not stable during that period.
【学位授予单位】：云南大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：Q914

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