Developmental and Structural Section
Madrid, Eric , Friedman, William E. .
Female Gametophyte Developmental Evolution in Piperales.
Piperales may have the most variable female gametophyte developmental patterns of any major angiosperm lineage. There are reports of transitions from monospory to bispory and tetraspory. There are at least four different patterns of tetrasporic female gametophyte development that produce central cells containing from two to fourteen nuclei, with corresponding endosperm levels ranging from triploid to decapentaploid. Of the ten basic patterns of female gametophyte development among angiosperms circumscribed by Maheshwari (1950), at least six occur in Piperales. Piperales are truly a “hotspot” of female gametophyte developmental evolution, and as such constitute the premier group for comparative investigations of divergent patterns of female gametophyte ontogeny.
We conducted a comparative investigation of female gametophyte development in Aristolochia labiata, Piper peltatum, Peperomia dolabriformis, and Peperomia hispidula. We combined light and laser-scanning confocal microscopy with three-dimensional computer reconstruction to describe nuclear position, vacuole morphology, and cell morphology throughout all stages of female gametophyte development. These data, along with the data of several recent studies in Piperales, allow us to propose specific hypotheses about how nuclear positioning events during early ontogenetic stages have led to the evolution of alternate derived female gametophyte ontogenies in Piperales. We discuss our findings within the context of developmental modularity, heterochrony, and the dynamics of embryo-nourishing tissues.
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1 - University of Colorado, Department of Ecology and Evolutionary Biology, Campus Box 334, Boulder, Colorado, 80309, United States
2 - University of Colorado, Department of Ecology and Evolutionary Biology, UCB 334, Boulder, Colorado, 80309, USA
Female gametophyte development
Presentation Type: Oral Paper:Papers for Sections
Date: Tuesday, July 29th, 2008
Time: 2:30 PM