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THE MECHANISM OF ACTION OF CALCIUM IN THE INHIBITION OF HIGH TEMPERATURE‐INDUCED LEAKAGE OF BETACYANIN FROM BEET ROOT DISCS
Author(s) -
COOKE A.,
COOKSON A.,
EARNSHAW M. J.
Publication year - 1986
Publication title -
new phytologist
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 3.742
H-Index - 244
eISSN - 1469-8137
pISSN - 0028-646X
DOI - 10.1111/j.1469-8137.1986.tb00825.x
Subject(s) - divalent , chemistry , membrane , turgor pressure , calcium , biophysics , choline , sugar beet , inorganic chemistry , biochemistry , organic chemistry , horticulture , biology
S ummary Effective inhibition of high temperature‐induced leakage of betacyanin from beet root discs occurs at concentrations of about 100 mM K + , Na + or choline + , about 10 mM inorganic divalent cations in which Mn 2+ Ca 2+ Sr 2+ Ba 2+ Mg 2+ , and about 1 mM, Ln 3+ . Thermal protection is also afforded by a range of sugars and sugar alcohols suggesting that the action of monovalent cation salts, in particular, is at least partially due to an osmotic lowering of cell turgor pressure. Inorganic divalent cation specificity, as well as the ineffectiveness of the organic cations, decamethonium 2+ and tris(ethylendiamine)cobaltic III, suggest that screening of membrane surface charge is not involved in decreasing betacyanin leakage. It is suggested that Ca 2+ , and other inorganic multivalent cations, act by binding to membrane components which may produce a decrease in membrane fluidity.