Change search
CiteExportLink to record
Permanent link

Direct link
Cite
Citation style
  • apa
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • Other style
More styles
Language
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Other locale
More languages
Output format
  • html
  • text
  • asciidoc
  • rtf
Efflux of Sucrose from Mesophyll Cells during Apoplastic Phloem Loading in Pea
Stockholm University.
1999 (English)Doctoral thesis, comprehensive summary (Other academic)
Abstract [en]

Efflux of sucrose from photosynthesizing mesophyll cells into the apoplastic space, during apoplastic phloem loading, was investigated using suspension of protoplasts and inside-out plasma membrane vesicles isolated from mature leaves of in Pisum sativum L. cv. Fenomen. Addition of exogenous sucrose to the suspension medium, affected the carbohydrate allocation but neither the photosynthesis nor respiration of the mesophyll cells. Furthermore, addition of low concentrations of sucrose and/or ABA (below 5 mmol/L and 10-7 mol/L, respectively) to the medium, caused an increase in sucrose efflux from the protoplasts. However, sucrose efflux decreased when the protoplasts were incubated in higher concentrations sucrose and/or ABA (above 15 mmol/L and 10-7 mol/L, respectively). During the sucrose efflux, there was an increase in the cytosolic pH of the mesophyll protoplasts which, however, decreased when PCMBS, an inhibitor of sucrose/H+ symport, was added to the protoplasts. On the other hand, cytosolic [K+] decreased during the sucrose efflux but increased when the release of sucrose from the mesophyll cells was inhibited by PCMBS. The uptake of sucrose into inside-out plasma membrane vesicles was dependent on sucrose content and pH, inhibited by PCMBS, and did not involve MgATPase activity. This work suggests that during the apoplastic phloem loading in pea, sucrose efflux from the photosynthesizing mesophyll cells into the apoplastic space occurs via facilitated-diffusion using a sucrose/H+ symporter on the plasma membrane. The process does not involve MgATPase activity but leads to a simultaneous decrease in cytosolic [K+]. Changes in the apoplastic environment, such as sucrose and/or ABA levels in the apoplast, have a significant effect on the sucrose efflux.

Place, publisher, year, edition, pages
Stockholm: Stockholm University , 1999. , 38 p.
National Category
Botany
Research subject
Physiological Botany
Identifiers
URN: urn:nbn:se:su:diva-64100ISBN: 91-7153-947-6 (print)OAI: oai:DiVA.org:su-64100DiVA: diva2:455187
Public defence
1999-06-05, 10:00
Opponent
Note
Härtill 4 uppsatserAvailable from: 2011-11-09 Created: 2011-11-09Bibliographically approved

Open Access in DiVA

No full text

By organisation
Stockholm University
Botany

Search outside of DiVA

GoogleGoogle Scholar

isbn
urn-nbn

Altmetric score

isbn
urn-nbn
Total: 71 hits
CiteExportLink to record
Permanent link

Direct link
Cite
Citation style
  • apa
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • Other style
More styles
Language
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Other locale
More languages
Output format
  • html
  • text
  • asciidoc
  • rtf