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首页> 外文学位 >A study of lichens using nuclear microscopy, scanning electron microscopy, and carbon-14 accelerator mass spectrometry.
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A study of lichens using nuclear microscopy, scanning electron microscopy, and carbon-14 accelerator mass spectrometry.

机译：使用核显微镜，扫描电子显微镜和碳14加速器质谱对地衣的研究。

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摘要

Lichens are symbiotic systems comprised of a fungus and an alga. Nuclear microscopy was used to study thin foliose lichen cross sections and lichen surfaces to determine element distributions. These distributions, along with scanning electron micrographs and other analyses, provide evidence for a unique function of calcium oxalate in the lichen family Parmeliaceae. Foliose lichens from the family Umbilicariaceae demonstrated no calcium oxalate accumulation. The lichen Dermatocarpon reticulatum also showed no calcium accumulation, but did demonstrate sulfur accumulation.; The results indicated that soluble elements of biological significance (i.e. phosphorus, sulfur, chlorine, and potassium) were often most concentrated around the algal layer. Transition metals also tended to be more concentrated around the algal layer. Elements associated with silicate minerals (silicon, titanium, iron, and manganese) were usually found in highest concentration in the lower and upper cortices.; Cross section data were inconclusive regarding pollution effects on lichen thalli, so scans of upper and lower cortices were done to determine the thallus element characteristics from an additional perspective. Element maps of Xanthoparmelia cumberlandia from Arizona show that particles are randomly distributed over the thallus. While still preliminary, this approach may further clarify the role of lichens as biomonitors of air pollution.; Accelerator mass spectrometry was used to measure 14C profiles in individuals of the crustose lichen Caloplaca trachyphylla at two sites. The profiles showed linear radial growth and an annual carbon turnover rate of 4.5%. Growth rates were constant for individuals at the same site, but differed by 80% between two sites. These data suggest that habitat has an important effect on growth. The implications of the data to lichenometry are also discussed. However, failure of the technique to measure growth rate in the crustose lichen Rhizocarpon geographicum represents a significant limitation.
机译：地衣是由真菌和藻类组成的共生系统。核显微镜用于研究薄叶苔藓的横截面和地衣表面，以确定元素分布。这些分布，连同扫描电子显微照片和其他分析，为地衣科草木科中草酸钙的独特功能提供了证据。来自脐带科的叶状地衣显示草酸钙没有积累。地衣皮质果皮也没有钙积累，但确实有硫积累。结果表明，具有生物学意义的可溶性元素（即磷，硫，氯和钾）通常最集中在藻层周围。过渡金属也倾向于在藻层周围更加集中。与硅酸盐矿物有关的元素（硅，钛，铁和锰）通常在下部和上部皮质中含量最高。关于污染对地衣藻的影响，断面数据尚无定论，因此需要对上部和下部皮质进行扫描，以从其他角度确定determine的元素特征。来自亚利桑那州的Xanthoparmelia cumberlandia的元素图谱显示，颗粒随机分布在the体上。这种方法虽然还很初步，但可以进一步阐明地衣作为空气污染生物监测器的作用。使用加速器质谱法在两个部位测量地壳地衣小叶锦鸡儿的14C谱。剖面显示出线性的径向增长，年碳周转率为4.5％。同一地点的个体的增长率是恒定的，但两个地点之间的增长率相差80％。这些数据表明栖息地对生长具有重要影响。还讨论了数据对地衣测量的影响。然而，该技术无法测量地壳地衣根瘤菌的生长速度，这是一个重大局限。

著录项

  • 作者

    Clark, Brett M.;

  • 作者单位

    Brigham Young University.;

  • 授予单位 Brigham Young University.;
  • 学科 Chemistry Analytical.; Biology Botany.
  • 学位 Ph.D.
  • 年度 2001
  • 页码 189 p.
  • 总页数 189
  • 原文格式 PDF
  • 正文语种 eng
  • 中图分类 化学;植物学;
  • 关键词

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