, Volume 201, Issue 2, pp 195–201

Symplasmic connections between sieve element and companion cell in the stem phloem ofVicia faba L. have a molecular exclusion limit of at least 10 kDa


DOI: 10.1007/BF01007704

Cite this article as:
Kempers, R. & van Bel, A.J.E. Planta (1997) 201: 195. doi:10.1007/BF01007704


High-molecular-weight fluorochromes were intracellularly injected into a sieve element of the fascicular stem phloem ofVicia faba L., using a modified membrane-potential-recording pressure probe. After stabilization of the membrane potential following microelectrode impalement, either LYCH (Lucifer Yellow CH), 4.4-kDa FITC-dextran (fluoresceinisothiocyanate-dextran) conjugate, or 3-kDa, 10-kDa or 40-kDa LYCH-dextran conjugate was microinjected into the sieve element. Longitudinal fluorochrome movement across the sieve plates and lateral displacement to the companion cells was detected with all the probes except the 40-kDa conjugate. This indicates that the molecular exclusion limit of the pore/plasmodesma units between a sieve element and a companion cell in the fascicular stem phloem ofVicia faba lies between 10 kDa and 40 kDa.

Key words

Fluorescent dextranIntracellular microinjectionMolecular exclusion limitPore/plasmodesma unitSieve element/companion cell complexVicia





Lucifer Yellow CH


molecular exclusion limit


pore/plasmodesma unit


sieve element/companion cell complex

Copyright information

© Springer-Verlag 1997

Authors and Affiliations

  1. 1.Transport Physiology Research Group, Department of Plant Ecology and Evolutionary BiologyUtrecht UniversityUtrechtThe Netherlands
  2. 2.Botanisches Institut 1Justus-Liebig UniversityGiessenGermany