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Aluminum‐dependent dynamics of ion transport in Arabidopsis : specificity of low pH and aluminum responses
Author(s) -
Bose Jayakumar,
Babourina Olga,
Shabala Sergey,
Rengel Zed
Publication year - 2010
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.1399-3054.2010.01377.x
Subject(s) - arabidopsis , aluminium , biophysics , ion , chemistry , dynamics (music) , biochemistry , chemical physics , biology , physics , gene , organic chemistry , mutant , acoustics
Low‐pH and Al 3+ stresses are the major causes of poor plant growth in acidic soils. However, there is still a poor understanding of plant responses to low‐pH and Al 3+ toxicity. Low‐pH or combined low‐pH and Al 3+ stress was imposed in order to measure rhizosphere pH, ion fluxes, plasma membrane potential and intracellular H + concentration in distal elongation and mature zones (MZs) along the longitudinal axis of Arabidopsis thaliana roots. Low‐pH stress facilitated H + influx into root tissues and caused cytoplasmic acidification; by contrast, combined low‐pH/Al 3+ treatment either decreased H + influx in the distal elongation zone (DEZ) or induced H + efflux in the MZ, leading to cytoplasmic alkalinization in both zones. Low‐pH stress induced an increase in rhizosphere pH in the DEZ, whereas combined low‐pH/Al 3+ stress resulted in lower rhizosphere pH in both root zones compared with the low‐pH treatment alone. Low‐pH stress facilitated K + efflux; the presence of Al 3+ diminished K + efflux or favored K + influx into root tissues. In both zones, low‐pH treatment induced plasma membrane (PM) depolarization, which was significantly diminished ( P ≤ 0.05) when combined stresses (low‐pH/100 µ M Al 3+ ) were imposed. After 60 min of exposure, low pH caused PM depolarization, whereas low pH/100 µ M Al 3+ caused PM hyperpolarization. Thus, low pH and Al 3+ toxicity differentially affect root tissues and, consequently, the rhizosphere, which might underpin the differential mechanisms of plant adaptation to these abiotic stresses.