Dissertation Research: Evolution of Floral Pattern Formation in Hibbertia (Dilleniaceae)

论文研究：Hibbertia（Dilleniaceae）花型形成的演化

• 批准号: 0105089
• 负责人: Paul Manos
• 金额: $ 1万
• 依托单位: Duke University
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2001
• 资助国家: 美国
• 起止时间: 2001-07-01 至 2004-06-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0105089&HistoricalAwards=false
• 关键词: Dissertation; Research; Evolution; Floral; Pattern

The goals of this study are: 1) to infer the phylogeny, or set of genealogical relationships, of Hibbertia using chloroplast and nuclear DNA sequences; 2) to document the pattern of floral development using Scanning Electron Microscopy for selected Hibbertia species; 3) compare the sequences of developmental events between species in the context of a relativistic time course, so that developmental events may be compared without the assumption that similar appearing stages in the of different species represent units for direct comparison. The combination of data on the pattern formation and relative timing of organ development will then be analyzed in a phylogenetic context, so that hypotheses of how relative changes in the timing of developmental events have affected mature floral form may be explicitly tested. Preliminary data suggests that in one major group of Hibbertia, the timing of the origination of the carpels (female floral organs) has been advanced, relative to the initiation of stamens (male, pollen-producing floral organs), so that the carpels take up space on the lower half the floral meristem (aggregation of undifferentiated, embryonic cells) that in other taxa produce stamens. The result of relative timing shift is the transition of a radially symmetric patterning of stamens around the flower, to a bilaterally symmetric arrangement of stamens formed exclusively on the top half of the flower. This study will be among the first to elucidate the evolutionary processes behind differences in floral morphology at the level of the floral groundplan.The study of floral morphological diversity stands as one of the principal foci of botanical research. While the implications of this field for flowering plant classification have been the most long-standing and far-reaching, the study of floral evolution impacts economically important disciplines such as horticulture and plant breeding. A group with particularly great potential to further our understanding of the evolution of floral form is Hibbertia (family Dilleniaceae), a genus of ca. 150 species distributed in Australia, New Caledonia, and Madagascar. What makes Hibbertia such an ideal candidate for such a study is, as put forth by the great evolutionary botanist G. L. Stebbins (1974), that "[t]here is probably no other genus of angiosperms that exhibits such a high degree of variation in those characteristics that are often regarded as 'fundamental' and are usually associated with the separation of genera or even higher categories."

本研究的目的是：1）利用叶绿体和核DNA序列推断Hibbertia属植物的亲缘关系，2）利用扫描电镜技术研究Hibbertia属植物的花发育模式; 3）在相对论时间进程的背景下比较物种之间的发育事件序列，因此，可以比较发育事件，而不必假设不同物种的相似出现阶段代表直接比较的单位。模式形成和器官发育的相对时间的数据的组合，然后将在系统发育的背景下进行分析，使假设的相对变化的时间发展事件如何影响成熟的花的形式可能会明确测试。 初步数据表明，在Hibbertia的一个主要类群中，心皮（雌性花器官）的起源时间相对于雄蕊（雄性，产生花粉的花器官）的起源已经提前，因此心皮占据了花分生组织（未分化的胚细胞的聚集体）下半部分的空间，在其他类群中产生雄蕊。 相对时间偏移的结果是围绕花的雄蕊的径向对称图案过渡到仅在花的上半部分上形成的雄蕊的双侧对称布置。 这项研究将是第一个阐明花形态差异背后的进化过程在花平面水平。花形态多样性的研究是植物学研究的主要焦点之一。 虽然这一领域对开花植物分类的影响是最长期和最深远的，但花的进化研究影响了园艺和植物育种等经济上重要的学科。 一组特别大的潜力，以进一步我们的理解花的形式是Hibbertia（家庭Dilleniaceae），属ca。150种分布于澳大利亚、新喀里多尼亚和马达加斯加。 正如伟大的进化植物学家G。L. Stebbins（1974）指出，“可能没有其他被子植物属在那些通常被认为是'基本'的特征上表现出如此高的变异程度，这些特征通常与属甚至更高类别的分离有关。"