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Ray F. Evert

Katherine Esau Professor of Botany and Plant Pathology*

Ph.D. (1958) University of California, Davis

Office: 334 Birge Hall
Phone: 608-262-2678
Email: rfevert@facstaff.wisc.edu

Developmental and physiological plant anatomy; phloem structure and function; leaf structure in relation to solute transport and phloem loading

*Dr. Evert is not accepting new students at this time.

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The principal research effort in this laboratory involves studies on the development and structure of the leaves of maize and barley, utilizing bright-field, transmission electron, epifluorescence, and confocal laser scanning microscopy. The developmental and structural studies are complemented by experimental studies aimed at determining: (1) the pathways followed by photoassimilates in source and sink leaves; (2) the sites and mechanisms of phloem loading and unloading in source and sink leaves, respectively; (3) the structural modifications associated with the sink-to-source conversion; and (4) the pathways followed by water, which enters the leaf in the transpiration stream, to intermediate, small, and transverse veins at various levels of leaves undergoing sink-to-source conversion. The experimental studies include: plasmolytic studies aimed at detecting the presence of existing concentration gradients in both source and sink portions of leaf blades and identifying sites of active loading; microautoradiographic studies aimed in part at determining the pathways followed by 14C-assimilates and identifying functional sieve tubes; and free-space marker (fluorescent dyes) studies aimed at determining the pathways followed by transpirational water at various levels of leaves undergoing sink-to-source conversion. 

Maize and barley, as other grass leaves, provide an excellent system for following a sequence of cellular and subcellular events precisely because polarized cell division at the base of the leaf results in an unmixed gradient of cell development. This same system is proving ideal for determining the underlying mechanisms of the sink-to-source transition. The leaves of maize and barley differ in many details both structurally and developmentally, in part because one is a C4 plant (maize) and the other a C3 plant (barley). Parallel studies on the leaves of both of these economically important grasses will provide a more balanced picture of structure-function relations in grass leaves than would an investigation of only one of them.

Recent Publications

Raven, P. H., R. F. Evert and S. E. Eichhorn. 1998. Biology of Plants, 6th ed. Worth Publishers, Inc., New York.

Farrar, J. J. and R. F. Evert. 1997. Seasonal changes in the ultrastructure of the vascular cambium of Robinia pseudoacacia. Trees 11:191-202.

Farrar, J. J. and R. F. Evert. 1997. Ultrastructure of cell division in the fusiform cells of the vascular cambium of Robinia pseudoacacia. Trees 11:203-215.

Evert, R. F., W. A. Russin and M. A. Bosabalidis. 1996. Anatomical and ultrastructural changes associated with sink-to-source transition in developing maize leaves. International Journal of Plant Science 157:247-261.

Evert, R. F., W. A. Russin and C. E. J. Botha. 1996. Distribution and frequency of plasmodesmata in relation to photoassimilate pathways and phloem loading in the barley leaf. Planta 198:572-579.

Russin, W. A., R. F. Evert, P. J. Vanderveer, T. D. Sharkey and S. P. Briggs. 1996. Modification of a specific class of plasmodesmata and loss of sucrose export ability in the sucrose export defective1 maize mutant. The Plant Cell 8:645-658.

Thomson, N., R. F. Evert and A. Kelman. 1995. Wound healing in whole potato tubers: a cytochemical, fluorescence, and ultrastructural analysis of cut and bruise wounds. Canadian Journal of Botany 73:1436-1450.

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© 2000 University of Wisconsin Department of Botany
Last updated: 19 November 2000