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In vivo binding of auxin to the plasmalemma and tonoplast of parenchymal cells in the wheat coleoptile
Author(s) -
Perbal Gérald,
DrissEcole Dominique
Publication year - 1988
Publication title -
biology of the cell
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.543
H-Index - 85
eISSN - 1768-322X
pISSN - 0248-4900
DOI - 10.1111/j.1768-322x.1988.tb00730.x
Subject(s) - coleoptile , auxin , vacuole , biology , cytoplasm , membrane , acetabularia , nucleus , biophysics , biochemistry , microbiology and biotechnology , gene
Tritiated auxin applied by an agar block on the wheat coleoptile tip for 2 hr was covalently fixed to adjacent protein by treatment with 1‐(3‐dimethylaminopropyl)‐3‐ethylcarbodiimide hydrochloride (DCC). The density of labelled auxin in the nucleus, the cell wall, the cytoplasm, and the vacuole was determined by autoradiography. Localization of tritiated auxin was studied at high resolution at the tonoplast and the plasmalemma lining the transverse (distal and proximal) and the longitudinal walls. The radioactivity along the tonoplast was always less than along the plasma membrane. The distribution of 3 H‐auxin was different across the longitudinal and transverse regions of the plasmalemma. The labelling was distributed asymmetrically on the longitudinal plasma membrane with a peak observed on the external surface. Tritiated auxin was distributed more symmetrically on the distal and the proximal plasma membranes. Our results are in agreement with the hypothesis that there are 2 different specific binding sites on the plasmalemma. The ratio of auxin present at the proximal and distal regions of the plasmalemma was 1.28.