Developmental and Structural Section
Feng, Chunmiao , Franks, Robert G. , Xiang, Qiu-Yun (Jenny) .
Comparative developmental study of inflorescence in Cornus.
Cornus (Dogwoods) contains four major lineages that are dramatically different in inflorescence architectures. They are partitioned into four morphological groups: 1) capitate cymes with petaloid bracts, 2) umbellate cymes with non-petaloid bracts, 3) large compound cymes with rudimentary bracts, and 4) small compound cymes with petaloid bracts. As the first step toward the investigation of molecular genetic causes underlying the inflorescence architecture divergence in the genus, we are conducting comparative histological analysis of different inflorescence types. Preliminary results show that the developments of the different inflorescence types varies in both mode and tempo, with some inflorescence and flower formed in the previous year soon after the anthesis in the spring (e.g., in Cornus florida), some developed in the current year (e.g., in C. canadensis), and others with inflorescence primordia preformed in the fall, but floral buds formed in the current spring (e.g, C. controversa). The development of capitate and umbellate cymes span seasons of two years. The shoot apical meristem develops into an inflorescence meristem soon after anthesis, followed by development of floral bud and completion of differentiation of floral parts by early fall. The inflorescence bud expands and flowers open in the spring of second year. The large compound cymes also start inflorescence meristem in fall, continue to produce primary and secondary branch meristems. The floral buds develop in following spring before elongation of internode of branches. Temporal and spatial expression of the Cornus leafy gene will be examined in these four inflorescence types using in situ hybridization. Transformation of leafy gene to Cornus canadensis, a transformation system established in our lab will be performed. Our long term goal is to identify the molecular basis of inflorescence divergence in these different species.
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1 - North Carolina State University, Department of Plant Biology, Campus Box 7612, Raleigh, North Carolina, 27695-7612, USA
2 - North Carolina State University, Department of Genetics
3 - North Carolina State University, Department of Botany, Campus Box 7612, Raleigh, North Carolina, 27695-7612, USA
In situ hybridization
Presentation Type: Oral Paper:Papers for Sections
Date: Tuesday, July 29th, 2008
Time: 10:15 AM