Poster: Membrane Transport

Abs # 1233: Electrophysiology of rice aleurone

Presenter:	Hay, Jordan O, joh4@cornell.edu
Authors	Hay, Jordan O (A)   Spanswick, Roger M (A)
Affiliations:	(A): Department of Biological and Environmental Engineering, Cornell University

The aleurone layer is located in the pathway that sucrose takes after it is unloaded from the phloem of the rice grain. As the most peripheral layer of the endosperm, the aleurone is nestled between the outer seed coat and the inner starchy endosperm. Plasmodesmata connect cells of the endosperm to each other but are absent between the endosperm and seed coat. The aleurone layer is likely to make an important contribution to the uptake of sucrose that is released into the apoplast by cells of the seed coat. Although it has been shown that aleurone cells in ripening grains express a sucrose/proton cotransport system [OsSUT1; Furbank et al. (2001), Aust. J. Plant Physiol. 28: 1187] and we have demonstrated saturable and nonsaturable components of uptake in aleurone protoplasts, electrophysiological studies of sucrose transport are lacking. Using microelectrode techniques, we have shown that negative membrane potentials can be recorded from cells of intact aleurone layers exposed to a bathing solution. This system should make it possible to test for sucrose-induced depolarization characteristic of sucrose/proton cotransport systems.