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Abstract Detail



Anatomy and Morphology

Zhang, Jingbo [1], Stevens, Peter [2], Zhang, Wenheng [3].

3-D modeling the inflorescence structures helps understanding floral zygomorphy development in Solanaceae.

In 1866, Wydler was the first to report that zygomorphic flowers of Schizanthus Ruiz & Pav. in the Solanaceae family possess a type of zygomorphy in which the gynoecium and zygomorphic corolla and androecium are along an oblique plane of symmetry. Later, Eichler (1869) and Robyns (1931) separately examined other genera of Solanaceae and found that oblique symmetry with a 36 degrees tilt exists in all genera in the family except for Nicandra Schreb.. The trait, therefore, has been considered as a synapomorphy for Solanaceae. However, other models were proposed to explain how floral symmetry developed here. For example, Gran and Gronbach (1984) thought that the flowers of Schizanthus developed upside down and rotated 180 degrees before anthesis; Cocucci (1989) agreed with the 36 degrees model for Schizanthus but proposed that the flowers rotated 72 degrees before anthesis; Ampornpan and Amstrong (1988-1991, 2002) claimed that Solanaceae did not have oblique floral symmetry at all. Here, we suggest that one way to advance our understanding of the development of floral zygomorphy in Solanaceae is to study the complicated structure of their sympodial inflorescences. We found that arguments about floral symmetry were largely due to disagreement over the position of the axis and bract that together define the median plane of the flower. Here, we report the 3-dimensional (3-D) structures of inflorescences for Browallia speciosa Hook., Capsicum sp., Cestrum sp., and Schizanthus grahamii Gill. representing phylogenetically divergent lineages of Solanaceae using 3-D modeling. This helps to clarify the underlying structure of the inflorescences, particularly the precise arrangement of organs on the branch. Most importantly, we propose a new model for the development of floral symmetry in Solanaceae which will guide ongoing molecular genetic work on the topic.


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1 - Department Of Biology, Virginia Commonwealth University, 1000 West Cary Street, Life Science Building 336, Richmond, VA, 23284, United States
2 - Missouri Botanical Garden, Po Box 299, St Louis, MO, 63166, United States
3 - Virginia Commonwealth University, Department Of Biology, 1000 W Cary Street, Richmond, VA, 23284, United States

Keywords:
3D modeling
Browallia
Capsicum
Cestrum
Floral development
floral morphology
floral symmetry
Schizanthus
Solanaceae
sympodial inflorescence.

Presentation Type: Oral Paper
Session: 13, Anatomy and Morphology II
Location: 113/Mayo Civic Center
Date: Monday, July 23rd, 2018
Time: 2:45 PM
Number: 13006
Abstract ID:832
Candidate for Awards:None


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