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Apoplastic and membrane‐associated Ca 2+ in leaves and roots as affected by boron deficiency
Author(s) -
Mühling Karl Hermann,
Wimmer Monika,
Goldbach Heiner E.
Publication year - 1998
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 - 10.1034/j.1399-3054.1998.1020204.x
Subject(s) - apoplast , chemistry , membrane , fluorescein isothiocyanate , boron , vicia faba , coumarin , fluorescence , biophysics , cell wall , biochemistry , botany , biology , organic chemistry , physics , quantum mechanics
A combination of fluorescein‐isothiocyanate (FITC), coumarin‐benzothiazol (BTC), and chlorotetracycline (CTC) fluorescence was used to simultaneously monitor apoplastic pH, apoplastic free Ca 2+ , and plasma membrane‐bound Ca 2+ . As early boron deficiency reactions supposedly include alterations of plasma membrane‐bound transport processes besides rapid effects on cell wall physical properties, the corresponding changes were followed in leaves and roots of Vicia faba L. cv. Troy. Boron deficiency did not alter the apoplastic pH, but it reduced plasma membrane‐bound Ca 2+ in roots at 4 h and leaves at 3 days after starting the deficiency treatment. The decrease in plasma membrane‐bound Ca 2+ coincided with an increase in apoplastic free Ca 2+ and K + , and occurred before the first visible symptoms were noticed. It is proposed that less Ca 2+ is bound to the plasma membrane due to a reduction of specific Ca 2+ ‐binding sites (borate esters with vic ‐diols or polyhydroxy‐carboxylates) before plasma membrane integrity deteriorates.