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Abstract Detail

Developmental and Structural Section

Zhao, Liang [1], Bachelier, Julien B. [2], Zhang, Xiao-hui [3], Luo, Ming-rong [4], Chang, Zhao-yang [1], Ren, Yi [3].

Floral organogenesis in Dysosma versipellis and its implications for the systematics and the evolution of petals in Berberidaceae.

Berberidaceae are one of the seven families of Ranunculales, and together, they form a robust monophyletic clade sister to all other eudicots. Because of their phylogenetic position, studies of floral organogenesis in Ranunculales are thus crucial to reconstructing the eudicots common ancestor, and a recent series of comparative studies already partially or totally covered six members of the order. Unfortunately, detailed studies on the floral organogenesis in Berberidaceae are still limited to only a few genera, and like in many other lineages, new inter- and infra-familial relationships recently proposed by molecular data have yet to be tested from a developmental perspective. Within Berberidaceae, the species of the chinese endemic genera Dysosma and Sinopodophyllum were first described in the genus Podophyllum, and their placement later in distinct genera was not universally accepted.  However, molecular phylogenetic studies recently suggested that Dysosma is indeed sister to the monotypic genera Podophyllum and Sinopodophyllum, and the floral organogenesis of Dysosma versipellis was studied using SEM to reevaluate these relationships. Preliminary results show that the development of the bisexual and polysymmetric flowers of D. versipellis is essentially similar to those of other Berberidaceae. All floral organs are free and initiated in successive and alternate trimerous whorls, until the floral apex is consumed by the development of a single and entirely ascidiate carpel. The petals are also delayed in development although, in contrast with some other members of the family, they do not produce nectar. The flowers of D. versipellis and other Berberidaceae also share a number of additional floral features that are common in (sapro)myophilous flowers, and like in other members of Ranunculales, the presence of floral nectaries is very important for the systematics of Berberidaceae. Their absence in D. versipellis and all other members of the Podophyllum group thus suggests that in this group, the nectarless petals are probably not homologous to the nectariferous petals of other Berberidaceae. However, in contrast with Podophyllum and most other taxa that have previously been studied, the petals of D. versipellis are not initiated from common stamen/petal primordia and show that a critical reevaluation of petal and nectary development is needed in Berberidaceae.  Together with the production of umbel-like inflorescences and flowers with red wrinkly petals, the absence in D. versipellis of secondary stamen primordia (which are found only in Podophyllum) also provides good support for Dysosma and Podophyllum and Sinopodophyllum as being three distinct, although closely related, genera.

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1 - Northwest A & F University, College of Life Sciences, Yangling, 712100, China
2 - SUNY Oswego, Department of Biological Sciences, 7060 Route 104, Oswego, NY, 13126-3599, USA
3 - Shaanxi Normal University, College of Life Sciences, Xi'an, 710062, China
4 - Northwest A & F University, College of Horticulture, Yangling, 712100, China

delayed petal development
floral development
floral nectaries
floral phyllotaxis
Podophyllum group

Presentation Type: Oral Paper:Papers for Sections
Session: 20
Location: Pines North/Boise Centre
Date: Tuesday, July 29th, 2014
Time: 9:15 AM
Number: 20005
Abstract ID:370
Candidate for Awards:None

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