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IONIC EQUILIBRATION OF THE SYMPLAST OF LOW‐SALT BARLEY ROOTS
Author(s) -
Bange G. G. J.
Publication year - 1978
Publication title -
acta botanica neerlandica
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.871
H-Index - 87
eISSN - 1438-8677
pISSN - 0044-5983
DOI - 10.1111/j.1438-8677.1978.tb00279.x
Subject(s) - symplast , chemistry , ion , ionic bonding , absorption (acoustics) , materials science , biochemistry , cell wall , organic chemistry , apoplast , composite material
SUMMARY Evidence is presented in support of the view that during the initial phase (lasting 1 to 3 hours) of Rb + absorption by low‐salt barley roots the root symplast comes close to equilibrium with the external Rb + solution. The characteristics of this state of equilibrium are:proportionality between the equilibrium content and the initial rate of entry into the symplast; reduction of influx which increases with the degree of saturation of the transport mechanism; a lower degree of specificity in the internal control of influx than in external uptake; temporary reduction of influx after a change of external conditions (from A to B) leading to a lower absorption rate, below the value prevailing after equal exposure to conditions B. These results are discussed on the basis of a tetrameric transport model in which there is an interplay of movement of ions in the free and in the bound state but in which no special feedback mechanisms are operating.