Jacques Dumais

Department of Organismic and Evolutionary Biology
Harvard University
Biological Laboratories Bldg. Room 1105
16 Divinity Ave., Cambridge, MA 02138

tel: (617) 496-0751; fax: (617) 384-5874
email: jdumais@oeb.harvard.edu
web: http://www.oeb.harvard.edu/faculty/dumais/dumais_home.html

Research Interests and Goals:

My research focuses on the mechanics and morphogenesis of plant development. Plant development is known to be controlled by mechanical factors which, in addition to more extensively studied molecular controls, contribute to the diversity of forms and patterns observed in plants. My personal philosophy is that the best way to explain developmental processes is with an approach that combines experimental work with simple computer models. The need for models is especially acute for problems of morphogenesis since they usually involve changes in space and time. I have therefore built a group that includes biologists, experimental physicists, and applied mathematicians to tackle these problems.

Work in the laboratory is divided in three main areas: cell morphogenesis, meristem growth, and the mechanics of fast movements.

Area 1: Cell Morphogenesis:
My interest in cell morphogenesis is motivated by the desire to explain how cell shape emerges from the activity of subcellular structures such as the cytoskeleton and the cellulosic wall. A special focus has been the plant cell wall because it is the nexus where molecular and mechanical factors come together. Over the last ten years, we have developed experimental and computational tools to measure the mechanical strains and stresses associated with plant and fungal cell morphogenesis. These two variables are the cornerstone of any mechanical analysis. We were able to establish a microstructural model that can account for tip growth in terms of wall structure, its material properties, and the turgor stresses acting on it (Bernal et al. 2007, Dumais et al. 2004, 2006).

Area 2: Meristem Growth:
The role of meristem growth in establishing the overall architecture of plants has also been an active area of research in the laboratory. I see this work as complementary to the detailed molecular work pursued by many research groups. We have recently developed surgical techniques to manipulate pattern formation at the apex of plants. We are now able to manipulate the meristem geometry and follow over time how organ initiation is affected. We are complementing these experimental observations with modeling using discrete geometrical dynamical systems.

Area 3: Fast Movements:
This area of research diverges slightly from the previous two but offers many interesting examples of the use of mechanics to support biological functions other than growth and development. We have so far focused mainly on the mechanics of dispersal in fungi, ferns, and orchids. Our observations have allowed us to state the key design principles to support dispersal in these taxa. We are now trying to develop biomimetic systems that make use of the same design principles.

 

Selected Publications:

Forterre, Y., Skotheim, J.M., Dumais, J. and Mahadevan, L. (2005). "How the Venus flytrap snaps." Nature 433: 421-425.

Hotton, S., Johnson, V., Wilbarger, J., Zwieniecki, K., Atela, P., Golé, C., Dumais, J. (2006). "The possible and the actual in phyllotaxis: Bridging the gap between empirical observations and iterative models." Journal of Plant Growth Regulation 25: 313-323.

Dumais, J., Shaw, S.L., Steele, C.R., Long, S.R. and Ray, P.M. (2006). "An anisotropic­viscoplastic model of plant cell morphogenesis by tip growth. " International Journal of Developmental Biology 50: 209-222.

Bernal, R.V., Rojas, E.R., and Dumais, J. (2007). "The mechanics of tip growth morphogenesis: what we have learned from rubber balloons." Journal of Mechanics of Materials and Structures 2: 1157-1168.

Dumais J. (2007). "Can mechanics control pattern formation in plants? " Current Opinion in Plant Biology 10: 58-62.

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