Symplastic Continuity between Companion Cells and the Translocation Stream: Long-Distance Transport Is Controlled by Retention and Retrieval Mechanisms in the Phloem

Description:

Article discussing symplastic continuity between companion cells and the translocation stream, and how long-distance transport is controlled by retention and retrieval mechanisms in the phloem.

Creator(s):
Creation Date: April 2003
Partner(s):
UNT College of Arts and Sciences
Collection(s):
UNT Scholarly Works
Usage:
Total Uses: 169
Past 30 days: 8
Yesterday: 1
Creator (Author):
Ayre, Brian G.

University of North Texas; Cornell University

Creator (Author):
Keller, Felix

University of Zürich

Creator (Author):
Turgeon, Robert

Cornell University

Publisher Info:
Place of Publication: [Rockville, Maryland]
Date(s):
  • Creation: April 2003
Description:

Article discussing symplastic continuity between companion cells and the translocation stream, and how long-distance transport is controlled by retention and retrieval mechanisms in the phloem.

Degree:
Department: Biological Sciences
Note:

Plant Physiology, April 2003, Vol. 131, pp. 1518-1528, www.plantphysiol.org/cgi/doi/10.1104/pp.012054; © American Society of Plant Biologists

Note:

Abstract: Substantial symplastic continuity appears to exist between companion cells (CCs) and sieve elements of the phloem, which suggests that small solutes within the CC are subject to indiscriminate long-distance transport via the translocation stream. To test this hypothesis, the distributions of exotic and endogenous solutes synthesized in the CCs of minor veins were studied. Octopine, a charged molecule derived from arginine and pyruvate, was efficiently transported through the phloem but was also transferred in substantial amounts to the apoplast, and presumably other non-phloem compartments. The disaccharide galactinol also accumulated in non-phloem compartments, but long-distance transport was limited. Conversely, sucrose, raffinose, and especially stachyose demonstrated reduced accumulation and efficient transport out of the leaf. The authors conclude that small metabolites in the cytosol of CCs do enter the translocation stream indiscriminately but are also subject to distributive forces, such as nonselective and carrier-mediated membrane transport and symplastic dispersal, that may effectively clear a compound from the phloem or retain it for long-distance transport. A model is proposed in which the transport or oligosaccharides is an adaptive strategy to improve photoassimilate retention, and consequently translocation efficiency, the phloem.

Physical Description:

11 p.

Language(s):
Subject(s):
Keyword(s): companion cells | phloem | sieve elements | minor veins
Source: Plant Physiology, 2003, Rockville: American Society of Plant Biologists, pp. 1518-1528
Partner:
UNT College of Arts and Sciences
Collection:
UNT Scholarly Works
Identifier:
  • DOI: 10.1104/pp.012054
  • ARK: ark:/67531/metadc81379
Resource Type: Article
Format: Text
Rights:
Access: Public
Citation:
Publication Title: Plant Physiology
Volume: 131
Page Start: 1518
Page End: 1528
Peer Reviewed: Yes