Kaplan Memorial Lecture - Dr. Nancy Dengler
Dengler, Nancy G. .
Inside Leaf Development.
Land plants display a striking diversity of external morphologies. Leaf size and shape are major contributors to this multiplicity of plant form in the natural world. Mature function of all leaves depends on the developmental coordination of leaf morphogenesis with the processes that give rise to cells and tissues on the inside of the leaf.. During development within the shoot tip, leaf shape is manifested very early, as basic leaf symmetry and sub-regions are apparent almost from inception on the shoot apical meristem. Initial leaf shape, as expressed during early primary morphogenesis, can be highly altered during leaf expansion and secondary morphogenesis, however. Histogenesis of internal tissues runs in parallel with the time course of morphogenesis: tissue patterning occurs during the earliest developmental stages, cell enlargement alters and enhances the initial differences among the tissue systems as leaves expand, and full cell differentiation is completed late, often after leaves reach full size. In some groups of plants, such as the palms and certain aroids, histogenetic processes can have surprising implications for morphogenesis, as leaf shape can change through remodeling of initial form late in development. Other linkages between leaf morphogenesis and histogenesis can be puzzling. In some cases external features such as size are strongly correlated structurally and developmentally with complexity of venation pattern; in other cases development of these features appears to be uncoupled. The diversification of photosynthetic pathways in the genus Flaveria (Asteraceae) provides a suitable model to examine some developmental links between morphogenesis and histogenesis and highlights how small developmental shifts can have large implications for mature form and function.
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1 - University of Toronto, Department of Ecology and Evolutionary Biology, 25 Willcocks St., Toronto, Ontario, M5S 3B2, Canada
Kaplan Memorial Lecture.
Presentation Type: Special Presentation
Location: Ballroom D/Convention Center
Date: Tuesday, August 3rd, 2010
Time: 5:00 PM