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The effect of a calcium‐channel antagonist, nifedipine and agonist, Bay K‐8644, on the phytochrome‐controlled swelling of etiolated wheat protoplasts
Author(s) -
Tretyn Andrzej,
Kendrick Richard E.,
Bossen Margreet E.
Publication year - 1990
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.1399-3054.1990.tb02086.x
Subject(s) - etiolation , phytochrome , protoplast , nifedipine , biophysics , swelling , dihydropyridine , agonist , channel blocker , antagonist , calcium , calcium channel , biology , botany , chemistry , biochemistry , receptor , materials science , enzyme , red light , organic chemistry , composite material
The effect of external Ca 2+ and Ca 2+ ‐channel modulators on the phytochrome‐controlled swelling of etiolated wheat ( Triticum aestivum L. cv. Arminda) mesophyll protoplasts has been studied. The red light (R)‐stimulated swelling of the protoplasts requires Ca 2+ in the surrounding medium and maximum response was observed in a medium containing I m M CaCI 2 . Far‐red light (FR) irradiation of protoplasts in the presence or absence of Ca 2+ does not influence the protoplast volume. The Ca 2+ ‐channel antagonist nifedipine prevents R‐induced protoplast swelling at very low concentrations (0.1 μ M ). The Ca 2+ ‐channel agonist Bay K‐8644 stimulates the swelling of protoplasts incubated in darkness or irradiated with FR. Action of nifedipine depends on whether it is applied before or after the R pulse. The results are compatible with the hypothesis that phytochrome controls the activity of dihydropyridine‐sensitive L‐type Ca 2+ channels.