Premium
Short‐term aluminium uptake by tobacco cells: Growth dependence and evidence for internalization in a discrete peripheral region
Author(s) -
Vitorello Victor A.,
Haug Alfred
Publication year - 1996
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.1399-3054.1996.tb00514.x
Subject(s) - trypan blue , morin , biophysics , chemistry , membrane permeability , nicotiana tabacum , cell , membrane , nuclear chemistry , biochemistry , biology , medicine , pathology , gene
Short‐term uptake and initial localization of aluminium (Al) were investigated in cultured cells of Nicotiana tabacum L. cv. BY‐2. Graphite furnace atomic absorption spectrometry and an in vivo Al‐sensitive fluorometric assay, employing morin, yielded similar results in all experiments. Aluminium uptake was critically dependent on cell growth. As opposed to negligible uptake in stationary‐phase cells, Al uptake (20 μ M AlCl 3 , pH 4.5, 23°C) by actively growing cells was detectable within 5 min, with an initial rate of 16 nmol Al (10 6 cells) −1 h −1 . Increased CaCl 2 levels (up to 20 m M ), low temperature (4°C), and pre‐chelation of Al to citrate greatly reduced Al uptake (by 75–90%). A pH‐associated permeabilization of cells at pH 4.5, as monitored by trypan blue, was observed in some growing cells. Although permeability to trypan blue was not a requirement for Al uptake, enhanced membrane permeability at pH 4.5, relative to pH 5.6, may contribute to Al uptake. Aluminium was observed to localize mainly in a pronounced and discrete fluorescent zone at the cell periphery (2–30 μm wide), presumably in the cortical cytosol and/or the adjoining plasma membrane section, although the possibility cannot be excluded that some Al resided in the cell wall apposing this discrete region. However, as judged by the Al‐morin assay, there were no detectable Al levels in the remaining, larger portion of the cell wall. The potential of the Al‐morin method in Al toxicity studies is illustrated.