• 主题
高级搜索  >
历史搜索 清空历史
首页> 外文学位 >Mechanisms defining ecological range limits in a Penstemon hybrid zone.
【24h】

Mechanisms defining ecological range limits in a Penstemon hybrid zone.

机译：定义Penstemon混合区生态范围限制的机制。

获取原文
获取原文并翻译 | 示例
页面导航
  • 摘要
  • 著录项
  • 相似文献
  • 相关主题

摘要

Hybrid zones, areas where divergent species cross-fertilize, can be used to study the mechanisms that isolate species. Studies of selection in hybrid zones indicate that endogenous factors like genomic incompatibilities as well as exogenous factors like pollinators and climate can be important in structuring species boundaries. I studied the role of endogenous and exogenous factors in determining the range limits of two perennial wildflowers, Penstemon newberryi and P. davidsonii, and their hybrids, along an elevational gradient in the Sierra Nevada mountains.; First, I measured floral morphology and surveyed pollinator visitation along the elevational gradient, identifying over 62 species of floral visitors. Morphological measurements were used to construct a plant hybrid index and examine the correlation with elevation and with floral visitors. The visitor community that visited P. davidsonii was somewhat distinct from the community that visited P. newberryi and hybrids. Eleven common pollinator species visited both parent species and could be contributing to hybrid formation.; In the second chapter, I identified physiological differences between both species and hybrids. Penstemon davidsonii had less negative pre-dawn and mid-day water potential, lower water-use-efficiency, and took less time to produce mature fruits than its montane relative, P. newberryi. Hybrids were mostly intermediate, but gas exchange traits differed depending on genotype.; In the third chapter, I investigated the relative importance of endogenous and exogenous isolation. I conducted a hand-pollination experiment in which the pure species and hybrids were crossed in all possible combinations. Hybrid crosses did not result in few seeds or less viable seeds. I performed a reciprocal transplant experiment, planting both species and hybrids into gardens at low, middle, and high altitudes. In each garden, the hybrid with the native cytoplasm had a higher survival rate, suggesting local adaptation to different elevations.; This study indicates that exogenous isolating mechanisms, like physiological and pollinator differences, act to maintain P. newberryi and P. davidsonii as distinct at the elevational extremes of their ranges. My results illustrate the importance of studying hybrid performance in multiple environments and in generating reciprocal hybrids to effectively test for isolating mechanisms in natural hybrid zones.
机译：杂种区，即不同物种交叉受精的区域，可以用来研究隔离物种的机制。杂种区选择的研究表明，内源性因素（如基因组不相容性）以及外源性因素（如授粉媒介和气候）在构建物种边界方面可能很重要。我研究了内源性和外源性因素在确定内华达山脉海拔梯度上的两个多年生野花，彭斯特蒙牛和P. davidsonii及其杂种的范围限制中的作用。首先，我测量了花的形态，并沿着海拔梯度调查了传粉者的走访次数，确定了62种以上的花者。形态学测量被用于构建植物杂种指数，并检查其与海拔高度和与花卉访客的相关性。访问过大卫氏疟原虫的访客社区与访问过纽伯利疟原虫和杂种的社区有所不同。 11个常见的传粉媒介物种拜访了两个亲本物种，并可能有助于杂种的形成。在第二章中，我确定了物种和杂种之间的生理差异。与山地亲缘种P. newberryi相比，戴维氏假单胞菌的黎明前和中午负水势较小，水分利用效率较低，并且生产成熟果实所需的时间更少。杂种大多处于中间，但气体交换性状因基因型而异。在第三章中，我研究了内源性和外源性隔离的相对重要性。我进行了人工授粉实验，其中纯种和杂种以所有可能的组合杂交。杂交杂交不会导致种子较少或种子存活率较低。我进行了互惠的移植实验，在低海拔，中海拔和高海拔的花园中种植了物种和杂种。在每个花园中，具有天然细胞质的杂种具有较高的存活率，表明局部适应了不同的海拔高度。这项研究表明，外源隔离机制，如生理和传粉媒介的差异，在维持其极端海拔高度时，能使新浆果伯氏杆菌和戴维森氏菌保持不同。我的研究结果说明了研究多种环境中的杂交性能以及生成对等杂交以有效测试自然杂交区隔离机制的重要性。

著录项

  • 作者

    Kimball, Sarah.;

  • 作者单位

    University of California, Irvine.;

  • 授予单位 University of California, Irvine.;
  • 学科 Biology Botany.; Biology Ecology.
  • 学位 Ph.D.
  • 年度 2007
  • 页码 109 p.
  • 总页数 109
  • 原文格式 PDF
  • 正文语种 eng
  • 中图分类 植物学;生态学（生物生态学）;
  • 关键词

  • 入库时间 2022-08-17 11:39:18

相似文献

  • 外文文献
  • 中文文献
  • 专利
获取原文

客服邮箱：kefu@zhangqiaokeyan.com

京公网安备：11010802029741号 ICP备案号：京ICP备15016152号-6 六维联合信息科技 (北京) 有限公司©版权所有

  • 客服微信

  • 服务号