ARS | Publication request: WALL - A MODEL OF LEAF TRANSPIRATION: ANALYSIS OF MECHANISMS AND VISUALIZATION

Submitted to: American Society of Agronomy
Publication Type: Abstract
Publication Acceptance Date: September 1, 2003
Publication Date: October 1, 2003
Citation: Pachepsky, Y.A., Walthall, C.L., Kaul, M., Daughtry, C.S. 2003. A model of transpiration: analysis of mechanisms and visualization [CD-ROM]. Crop Science Society of America, Soil Science Society of America. Denver, Colorado: Agronomy Society of America.

Technical Abstract: Water flow in plants is a passive process that occurs in response to physical forces. Plants can control transpiration only indirectly via stomatal movements and/or changing the water permeability of the cuticle. Empirical estimates of non-stomatal transpiration range from 10 to 70 percent of the total. The quantitative anatomy of the epidermis, cuticle, and cell walls were used to describe liquid water transport inside a leaf. Cuticular resistance to water movement, considered previously as a single parallel link to stomatal transpiration, was partitioned in a new model (WALL) into (1) resistance to water movement in liquid films on the surfaces of cells, and (2) resistance of the cuticle. Liquid water transport inside a leaf caused by atmospheric VPD was described as a combination of hydraulic flux in microtubes (veins), film flow on cell walls, and flow through a microporous medium (cuticle). This was visualized with an L-system virtual model. Estimates of the cuticular transpiration showed it to be a more significant component of total transpiration than previously thought. The results have implications for furthering our understanding of plant drought tolerance and stress resistance.