The Experts below are selected from a list of 315 Experts worldwide ranked by ideXlab platform

James R. Manhart - One of the best experts on this subject based on the ideXlab platform.

Elizabeth A Zimmer - One of the best experts on this subject based on the ideXlab platform.

  • one size fits all molecular evidence for a commonly inherited petal identity program in ranunculales
    American Journal of Botany, 2009
    Co-Authors: David A Rasmussen, Elena M Kramer, Elizabeth A Zimmer
    Abstract:

    Petaloid organs are a major component of the floral diversity observed across nearly all major clades of angiosperms. The variable morphology and development of these organs has led to the hypothesis that they are not homologous but, rather, have evolved multiple times. A particularly notable example of petal diversity, and potential homoplasy, is found within the order Ranunculales, exemplified by families such as Ranunculaceae, Berberidaceae, and Papaveraceae. To investigate the molecular basis of petal identity in Ranunculales, we used a combination of molecular phylogenetics and gene expression analysis to characterize APETALA3 (AP3) and PISTILLATA (PI) homologs from a total of 13 representative genera of the order. One of the most striking results of this study is that expression of orthologs of a single AP3 lineage is consistently petal-specific across both Ranunculaceae and Berberidaceae. We conclude from this finding that these supposedly homoplastic petals in fact share a developmental genetic program that appears to have been present in the common ancestor of the two families. We discuss the implications of this type of molecular data for long-held typological definitions of petals and, more broadly, the evolution of petaloid organs across the angiosperms.

Hugh D. Wilson - One of the best experts on this subject based on the ideXlab platform.

Ying-xiong Qiu - One of the best experts on this subject based on the ideXlab platform.

Yi Ren - One of the best experts on this subject based on the ideXlab platform.

  • Diversity of petals in Berberidaceae: development, micromorphology, and structure of floral nectaries.
    Protoplasma, 2021
    Co-Authors: Liang Zhao, Yi Ren, Xiao-hui Zhang
    Abstract:

    Petals are important floral organs that exhibit considerable morphological diversity in terms of colour, shape, and size. The varied morphologies of mature petals can be linked to developmental differences. The petals of Berberidaceae (a core group of Ranunculales) range from flat sheets to complex structures with nectaries, but studies on petal development and structural diversity in this group are lacking. Here, the petal development, structure, and micromorphology of seven Berberidaceae genera are characterized by microscopy to clarify the diversity of petals within this group. The results indicate that no common petal-stamen primordium exists, that petal development proceeds through five stages, and that the differentiation responsible for the diversity of the mature petals occurs during stage 4. Processes contributing to the morphological diversity of mature petals include edge thickening, gland formation, and spur formation. Nandina and Diphylleia lack nectaries. Gymnospermium has saccate nectaries, Caulophyllum has nectaries on the petal margin, Epimedium has spur nectaries, and Berberis and Mahonia have glands at the base of petals. Petal nectaries usually consist of a secretory epidermis, two to twenty layers of secretory parenchyma cells, and vascular tissues. Eleven distinct cell types were observed in the petal epidermis, three of which are secretory; papillose cells appear to be absent in Diphylleia, which shows relatively little micromorphological variation. The ancestors of Berberidaceae may have nectaries in thickened areas of their petals. The micromorphology and nectary structures of the petals in Ranunculales are also compared.

  • Floral organogenesis in Dysosma versipellis (Berberidaceae) and its systematic implications
    Botany, 2016
    Co-Authors: Liang Zhao, Xiao-hui Zhang, Julien B. Bachelier, Yi Ren
    Abstract:

    The Berberidaceae and the six other families of Ranunculales form a sister clade to all other eudicots, and are crucial to reconstructing the common ancestor of flowering plants. Previous studies have suggested that the petals of most Berberidaceae are derived from stamens, and some are thought to develop petals from common petal/stamen primordia. However, the flower ontogeny is still poorly known in the family and the presence of common primordia needs to be re-evaluated from a comparative developmental perspective. Here, we used scanning electron microscopy to study the floral development of the endemic Chinese species Dysosma versipellis (Hance) M. Cheng ex Ying, which was originally placed in Podophyllum. Our results show that the floral organs are all free and the sepals, petals, and stamens are initiated centripetally in successive and alternate trimerous pairs of whorls around a single carpel. The nectarless petals are initiated separately and do not develop from common primordia with the stamens. ...