Education

• Ph.D. 1988 (Distinction) - University of Guelph
• B.Sc. 1966 (First Class Honours, Botany) - University of British Columbia

Teaching Interests Developmental Plant Anatomy (Fall), Plant Diversity and Evolution (Spring)

Research Interests

Comparative Morphology of the Vitaceae (Grape Family)

The Vitaceae is not a well-studied family. Currently, its systematic relationship to other Eudicots is unclear, and published phylogenies for the family leave many unanswered questions. Our lab is conducting a long-running comparative study that looks at the vegetative and floral development in a number of genera in the family. Shoot architecture is unique to this family. The shoot apical meristem (SAM) produces both leaf and uncommitted primordia (capable of developing into either tendrils or inflorescences). There are five known architectural patterns in the family, but these are specific, not generic characters. Tendrils may arise monopodially, sympodially, or as a bifurcation of the SAM, even for different species exhibiting the same architectural pattern. Our comparative analysis of the primary vascular patterns in species of Vitis and Cissus showed that the architectural pattern with both continuous tendrils and axillary buds is most likely derived, and that the ancestral pattern was most likely that in which tendrils are lacking.

Leaf morphology in this family is variable, from simple to multipinnate. This variability is also evident in heteroblastic leaf development, shown most dramatically by Leea guineensis. Currently, Benjamin Doughan MS student, is carrying out a morphometric analysis of Ampelopsis cordata (simple leaves) and Ampelopsis arborea (compound leaves) to compare their initiation and developmental trajectories.

In conjunction with Dr. Usher Posluszny, of the Department of Integrative Biology at the University of Guelph, we have examined floral morphology and ontogeny in several genera (Vitis, Parthenocissus, Ampelopsis, Cissus, Leea, Cyphostemma and Rhoicissus), and when combined with recent phylogenies for the family, we have concluded that Leea has a number of derived characters and its floral morphology and development is quite different in a number of respects from that in the rest of the family. Ampelopsis may have the fewest derived features, and Vitis the most. The other species are intermediate. We are continuing this work by adding Tetrastigma and Cayratia to our pool of information.

UNI Experimental Vineyard, Grapevine Identification

In 1997 we established a small vineyard on the UNI Campus, in which we are testing about 18 varieties of grape, both table and wine, for cold hardiness and disease resistance in northeast Iowa. As might be expected, the most hardy and reliable varieties are hybrids with some North American ancestry. This work has been supported by grants from the Carver Foundation, and the Prem Sahai Distinguished Professorship.

In 2004, with funding from the College of Natural Sciences, and under the leadership of Dr. Emily Lehman, we began a project to fill the need for straightforward, reliable morphological identification of grapevine varieties grown in the Midwest. This culminated in the publication of our Handbook in December 2004. Work is continuing to expand the number of varieties included in the Handbook and to develop microsatellite markers for use in further identification of varieties. This latter project is being done in conjunction with colleague Dr. James Jurgenson.

Phi Thickenings in Gymnosperm Roots

Phi thickenings are lignifications of the tangential and radial cortical walls in some roots. They are present in a number of tree species that dominate cliff ecosystems. We have established that their occurrence is correlated with current hypotheses of gymnosperm phylogeny. In conjunction with the Cliff Ecology Research Group in the Department of Integrative Biology at the University of Guelph, headed by Dr. Doug Larson, we have further examined the effects of waterlogging and soil compaction on their formation, and concluded that the environment can affect their degree of development. Currently, graduate student Deana Lickteig is working to further understand the role these structures may play in root growth and development, using Thuja occidentalis and T. plicata as her models.

Professional Accomplishments

Gerrath, J.M., and U. Posluszny. 2007. Shoot architecture in the Vitaceae. Canadian Journal of Botany (in press).

Wilson, T.C., Gerrath, J. M., and U. Posluszny. 2006. Morphological and anatomical development in the Vitaceae. VIII. Comparative development of three Cyphostemma (Vitaceae) species reveals important vegetative and reproductive differences among the species. Canadian Journal of Botany 84:702-716.

Lehman, E., and J. Gerrath. 2004. "A Midwesterner's Handbook to Grapevine Varieties" University of Northern Iowa College of Natural Sciences, Cedar Falls. 36pp.

Gerrath, J. M., L. Covington, J. Doubt, and D. A. Larson. 2002. Occurrence of phi thickenings is correlated with gymnosperms systematics. Canadian Journal of Botany 80:852-860.

Gerrath, J. M., U. Posluszny, and N. G. Dengler. 2001. Primary vascular patterns in the Vitaceae. International Journal of Plant Sciences 162:729-745.

Responsibilities Operation and maintenance of the departmental scanning electron microscope (a Tescan Vega 5136MM) model, installed in Fall, 2003.

International Experience

Visiting Scientist, Department of Integrative Biology, University of Guelph. 2005-

Grants History Iowa Department of Agriculture and Land Stewardship July 1 2005-June 30, 2007 (with James Jurgenson). "Development of DNA Markers for Identification of Midwestern Grape Varieties". $30,000.

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