Plant Physiol. Drug Metab Dispos
HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS
QUICK SEARCH:   [advanced]


     

Plant Physiology 99:643-651 (1992)
© 1992 American Society of Plant Biologists

This Article
Right arrow Full Text (PDF)
Right arrow Alert me when this article is cited
Right arrow Alert me if a correction is posted
Services
Right arrow Email this article to a friend
Right arrow Similar articles in this journal
Right arrow Similar articles in Web of Science
Right arrow Similar articles in PubMed
Right arrow Alert me to new issues of the journal
Right arrow Download to citation manager
Right arrow reprints & permissions
Citing Articles
Right arrow Citing Articles via CrossRef
Right arrow Citing Articles via Web of Science (16)
Right arrow Citing Articles via Google Scholar
Google Scholar
Right arrow Articles by Ellis, E. C.
Right arrow Articles by Spanswick, R. M.
Right arrow Search for Related Content
PubMed
Right arrow PubMed Citation
Right arrow Articles by Ellis, E. C.
Right arrow Articles by Spanswick, R. M.
Agricola
Right arrow Articles by Ellis, E. C.
Right arrow Articles by Spanswick, R. M.
Development and Growth Regulation

Quantitative Analysis of Photosynthate Unloading in Developing Seeds of Phaseolus vulgaris L. 1

II. Pathway and Turgor Sensitivity

Erle C. Ellis, Robert Turgeon and Roger M. Spanswick

Section of Plant Biology, Division of Biological Sciences, Cornell University, Ithaca, New York 14853-5908

Phloem import and unloading in perfused bean (Phaseolus vulgaris L.) seed coats were investigated using steady-state labeling. Though photosynthate import and unloading were significantly reduced by perfusion, measurements of photosynthate fluxes in perfused seed coats proved useful for the study of unloading mechanisms in vivo. Phloem import was stimulated by lowered seed coat cell turgor, as demonstrated by an increase in tracer and sucrose import to seed coats perfused with high concentrations of an osmoticum. The partitioning of photosynthates between retention in the seed coat and release to the perfusion solution also was turgor sensitive; increases in seed coat cell turgor stimulated photosynthate release to the apoplast at the expense of photosynthate retention within the seed coat. There was no evidence of a turgor-sensitive sucrose uptake mechanism in perfused seed coats. Thus, the turgor sensitivity of photosynthate partitioning within perfused seed coats was consistent with a turgor-sensitive efflux control mechanism. Measurements of tracer equilibration and sugar partitioning in perfused seed coats provided strong evidence for symplastic phloem unloading in seed coats.

1 Supported by grant 87-CRCR-1-2397 from the U.S. Department of Agriculture (R.M.S.), grant DCB-8803837 from the National Science Foundation (R.T.), and funds provided by the Hatch Program.






HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS
ASPB Publications PLANT PHYSIOLOGY® THE PLANT CELL
Copyright © 1992 by the American Society of Plant Biologists