This Article Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Services Email this article to a friend Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via HighWire Citing Articles via CrossRef Citing Articles via Google Scholar Google Scholar Articles by Thomas, P. A. Articles by Crawford, C. G. Search for Related Content PubMed PubMed Citation Articles by Thomas, P. A. Articles by Crawford, C. G. Agricola Articles by Thomas, P. A. Articles by Crawford, C. G.

Metabolism and Enzymology

Sugar Uptake and Metabolism in the Developing Endosperm of Tassel-seed Tunicate (Ts-5 Tu) Maize

U.S. Department of Agriculture, Agricultural Research Service, National Center for Agricultural Utilization Research, Seed Biosynthesis Research Unit, Peoria, Illinois 61604

Factors regulating assimilate transport into developing maize (Zea mays L.) kernels have been difficult to determine because of the structural complexity of basal kernel tissues and the damage that results from tissue dissection. The sensitivity of maize kernels to experimental manipulation is such that substantial maternal tissue is required to support kernel growth in vitro. Consequently, sugar transport experiments with isolated seed tissues or detached kernels have not unequivocally demonstrated how sugar transport occurs. In the present study, Tassel-seed Tunicate (Ts-5 Tu) maize kernels were investigated as a model system for introducing test solutions into the pedicel apoplast with minimal wounding. Transpiration in leafy glumes drew ¹⁴C-sugar solutions up the 8- to 10-millimeter-long pedicel stalks into the basal endosperm transfer cell region. ¹⁴C from fructose was incorporated into starch for 8 days. Sugar uptake into endosperm and embryo tissue showed specificity and inhibitor sensitivity. In particular, p-chloromercuribenzene sulfonate partially inhibited fructose uptake into the endosperm but had no effect on the metabolic conversion of that fructose that entered the endosperm. These results are consistent with active, carrier-mediated sugar transport, but a definitive determination would require more detailed tissue analysis. We propose that further refinement of the incubation solution may allow long-term kernel growth without cob tissue and thus provide a more precise determination of which maternal factors influence seed development.

² Present address: USDA, ARS, Plum Island Animal Disease Center, P.O. Box 848, Greenport, NY 11944.

This article has been cited by other articles:

				J. W. Patrick and C. E. Offler Compartmentation of transport and transfer events in developing seeds J. Exp. Bot., April 1, 2001; 52(356): 551 - 564. [Abstract] [Full Text] [PDF]