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The electroosmotic theory of phloem transport: a final restatement
Author(s) -
SPANNER D. C.
Publication year - 1979
Publication title -
plant, cell and environment
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.646
H-Index - 200
eISSN - 1365-3040
pISSN - 0140-7791
DOI - 10.1111/j.1365-3040.1979.tb00781.x
Subject(s) - phloem , potassium , ion transporter , ion , chemistry , biophysics , transmembrane protein , connection (principal bundle) , chemical physics , botany , biochemistry , biology , engineering , mechanical engineering , organic chemistry , receptor
The electroosmotic theory as published in 1974 is subjected to a detailed re‐examination, mainly in connection with the problems of anion transport and of the sheer magnitude of the transmembrane potassium current it necessitates. The result is a fundamental modification of the theory which appears very promising. A proton excretion pump replaces the potassium pump; anion transport now presents little difficulty. A modification of the scheme is proposed to incorporate plants like Cucurbita whose P‐protein is basic. The new suggestions appear to offer themselves fairly readily to experimental test. Anion transport in the phloem appears to differ somewhat fundamentally from cation transport.