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题名	古尔班通古特沙漠生物结皮中藓类植物多样性研究
作者	王红玲
学位类别	博士
答辩日期	2007
授予单位	中国科学院．新疆生态与地理研究所
导师	张元明，新疆生态与地理研究所
关键词	荒漠藓类
其他题名	On the Moss Diversity in Biological Soil Crust in the Gurbantunggut Desert
中文摘要	本文应用传统形态解剖学和分子标记手段对新疆古尔班通古特沙漠生物结皮中藓类植物多样性进行了研究。在详细的野外调查和标本鉴定基础上，探明了组成荒漠生物结皮的藓类植物的种类组成包括：丛藓科(Pottiaceae)墙藓属(Tortula)的刺叶墙藓(Tortula desertorum Broth.)、泛生墙藓(Tortula muralis Hedw.)和泛生墙藓无芒变种(Tortula muralis var. aestiva Brid. ex Hedw.)；流苏藓属(Crossidium)的绿色流苏藓(Crossidium chloronotos (Brid.) Limpr.)以及真藓科(Bryaceae)真藓属(Bryum)的真藓(Bryum argenteum Hedw.)，共计2科3属4种1变种。刺叶墙藓和真藓是组成古尔班通古特沙漠藓类结皮的优势种。利用徒手切片法对其形态解剖特征进行了研究，结果表明所有藓类植物叶片都具有明显或粗壮的中肋，茎皮部外层细胞壁不同程度加厚。叶片背卷或内卷、具疣状突起、透明毛尖(泛生墙藓无芒变种除外)以及边缘细胞壁加厚等特征，这些特征与藓类植物耐旱性有关。对生长在古尔班通古特沙漠和博格达山地针叶林的真藓的形态特征进行了对比研究。结果表明，两者在株高、叶长、毛尖长度和中肋宽度4个指标上表现出极显著差异(P<0.01)，毛尖长度变异最大，是藓类植物对干旱胁迫的形态适应。古尔班通古特沙漠中，刺叶墙藓优势分枝类型为二叉分枝，其次为单一不分枝。分枝类型与土壤理化性质无显著相关性，这可能是其内在的遗传基础所决定。采用撒茎法对刺叶墙藓进行沙培实验。结果表明，在不添加任何营养元素或激素的原沙基质培养条件下，刺叶墙藓植株碎片仍然能够生长并发育成完整的植物体。刺叶墙藓植株碎片在2mm时生长较好，大于2mm的沙埋深度则抑制其生长。沙埋也是影响古尔班通古特沙漠藓类植物生长和分布的因素之一。利用改进CTAB法、NaOH法和direct PCR amplication法对刺叶墙藓基因组DNA提取效果进行了研究。结果表明，CTAB法提取效果较好，并建立了最优ISSR扩增反应体系。利用ISSR分子标记对荒漠刺叶墙藓居群的遗传多样性水平进行研究，发现居群具有高水平的遗传多样性(HS=0.2135)，居群间的遗传分化(FST=0.0146)显著的小(P<0.001)，且居群间具有较高的遗传相似度。这表明中等尺度空间的地理隔离未对刺叶墙藓居群造成遗传上的隔离。居群高水平的遗传多样性的保持可能主要是由于居群间较强的基因流(Nm＝2.94)。由此推断，荒漠生境中刺叶墙藓居群在冬春有融雪的条件下可能存在一定的有性繁殖并产生成熟孢子。孢子通过风的传播进行长距离的扩散到达新的生境并生存定居。同时，这种高水平的遗传多样性也暗示着刺叶墙藓具有较强的适应干旱荒漠环境的能力。The Methods of traditional morphology and anatomy and ISSR(Inter Simple Sequence Repeat) molecular marker were used to study the morphological adaptation and population genetic diversity of mosses in biological soil crust in the Gurbantunggut Desert, Xinjiang. Based on the comprehensive investigating and identifying of specimen, the moss species that forming desert biological crust were detected. They belong to 2 families (Pottiaceae & Bryaceae) and 3 genera (Tortula, Crossidium & Bryum), including 4 species(Tortula desertorum Broth., Tortula muralis Hedw., Crossidium chloronotos (Brid.) Limpr., Bryum argenteum) and 1 variety(Tortula muralis var. aestiva Brid. ex Hedw.) The morphological and anatomical structures of these desert mosses were observed by hand section, and showed distinct midribs on the leaves and obvious incrassation of external cortex of stems. Some characteristics of morphological structures, such as leaf outcurve or concave, papillose, atop hairs (except T. muralis var. aestiva Brid. ex Hedw.) and thicked wall of marginal cells, are the long-term adaptation to the desert environments. By comparing morphological characteristics of B. argenteum distributed in the entirely different habitats of the Gurbantunggut Desert and Bogda Mountain, we found that the individual size, leaf length, atop hair length and midrib width of B. argenteum from the Gurbantunggut Desert were greater than the one from Bogda Mountain, and difference are significant(P<0.01). Atop hair length had a greatest variation among these characteristics, which was perhaps a response of morphological plasticity to harsh environment. Branching pattern of T. desertorum was predominant with dichotomous branching, followed by single branching. There had no significant difference between branching pattern and soil physics-chemical characteristics. It is presumably suggested that branching pattern of T. desertorum was associated with inherit genetic basis. The effects of sand burial depths on growth of T. desertorum were studied. The results showed that the fragments of T. desertorum could grow on sand medium without any nutrition element or hormone supply. The fragments of T. desertorum could grow only under 2mm sand-thickness. Sand burial is a factor to determine the distribution of T. desertorum in the Gurbantunggut Desert. Isolation of genomic DNA from T. desertorum in the moss biological crust by using the methods of modified CTAB, NaOH extraction and direct PCR amplification was contrasted. It showed that the content and purity of genomic DNA by the method of modified-CTAB is very high, and an optimal ISSR reaction system was established. Additionally, once the direct PCR amplification is mastered, it is a most convenient method for DNA extraction of desert moss, and would be applied broadly. The molecular method of inter simple sequence repeat (ISSR) was used to evaluate the genetic diversity of four populations of T. desertorum from the Gurbantunggut Desert for the first time. The results showed there had a higher level of population genetic diversity (HS=0.2135). A very low value of genetic variety (FST=0.0146) indicate very low significant genetic differentiation among populations (P<0.001), while high genetic variation within populations. There was a high level of gene flow (Nm=2.94) among populations, and had no geographical isolation at spatial distribution because of the similar genetic identity. High genetic variation could maintain by the high level of gene flow. Combining the findings, we conclude that the high genetic diversity observed for this species is most likely explained by a preponderance of sexual reproduction when snow melting in the Gurbantunggut Desert. They produced mature spores which could disperse over a long distance to the new habitat. Additionally, it is suggested that the higher genetic diversity in population T. desertorum probably the stronger adaptation ability to xeric habitats.
语种	中文
学科主题	微生物学
公开日期	2010-11-12
页码	共122页
内容类型	学位论文
源URL	[http://ir.xjlas.org/handle/365004/7904]
专题	新疆生态与地理研究所_中国科学院新疆生态与地理研究所(2010年以前数据)
推荐引用方式 GB/T 7714	王红玲. 古尔班通古特沙漠生物结皮中藓类植物多样性研究[D]. 中国科学院．新疆生态与地理研究所. 2007.

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