Our research in plant anatomy and development focuses on two fundamental questions of plant developmental biology.
1. What are the basic mechanisms of histogenesis?
Histogenesis encompasses the developmental specification of vascular, dermal and ground tissue systems (radial pattern formation), patterns of cell proliferation and enlargement within each tissue system, and the differentiation of specialized cell types. We are particularly interested in the formation of primary vascular pattern during shoot and leaf development. While dermal and ground tissues are derived from precursors within the shoot apical meristem, vascular tissue pattern is formed de novo from ground tissue precursors. We have combined anatomical approaches with the use of molecular markers of procambium identity and cell cycling to study the developmental relationship between vascular pattern formation and distinctive spatial and temporal patterns of cell division in Arabidopsis.
2. How are histogenic mechanisms altered during the evolution of structural adaptions?
One of the best-known examples of such alteration is the concomitant appearance of Kranz anatomy and photosynthetic biochemistry during the evolution of C4 species from their C3 ancestors. The evolution of Kranz anatomy requires alteration of vein spacing, modifications of patterns of cell division and cell enlargement within photosynthetic ground tissues, and specialization of mesophyll (PCA, primary carbon assimilation) and bundle sheath (PCR, photosynthetic carbon reduction) cells. This suite of anatomical characteristics has evolved repeatedly during the diversification of flowering plants. We are currently studying the convergence of structure, physiology and biochemistry in several families of dicotyledons. We are particularly interested in the evolutionary modification of vein pattern and spacing in the genus Flaveria (Asteraceae).
Department of Botany
University of Toronto
contact: Dr. Nancy G. Dengler