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The surface charge density of wheat root membranes
Author(s) -
Bérczi Alajos,
Møller Ian M.,
Lundborg Tomas,
Kylin Anders
Publication year - 1984
Publication title -
physiologia plantarum
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.351
H-Index - 146
eISSN - 1399-3054
pISSN - 0031-9317
DOI - 10.1111/j.1399-3054.1984.tb05166.x
Subject(s) - chemistry , surface charge , analytical chemistry (journal) , membrane , ion , charge density , botany , chromatography , biology , biochemistry , physics , organic chemistry , quantum mechanics
Seedlings of winter wheat ( Triticum aestivum L. cv. Hildur) were grown at 18°C for 7 days in darkness in a complete growth medium in the presence or absence of 1 m M KCl to produce roots with different ion contents (high and low K + respectively). The roots were homogenized, the 3 000 g, 10 000 g, 30 000 g (further fractionated by two phase partitioning) and 100 000 g pellets isolated, and their surface charge densities (σ) determined by the use of 9‐aminoacridine fluorescence. The average σ for all membrane fractions weighted for protein content was the same (−18 mC m −2 ) for low and high K + roots. The K + , Na + , Mg 2+ and Ca 2+ content of roots was determined and used to calculate an average σ following the procedure of Bérczi et al. [Physiol. Plant. 61: 529–534 (1984)]. The predicted value (−11 mC m −2 ) does not deviate much from the experimentally determined value. It is concluded as a useful working hypothesis that the average surface charge density is constant and that the ionic content of plant cells is regulated such that the average surface potential is constant.