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Altered cell wall properties are responsible for ammonium‐reduced aluminium accumulation in rice roots
Author(s) -
WANG WEI,
ZHAO XUE QIANG,
CHEN RONG FU,
DONG XIAO YING,
LAN PING,
MA JIAN FENG,
SHEN REN FANG
Publication year - 2015
Publication title -
plant, cell and environment
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.646
H-Index - 200
eISSN - 1365-3040
pISSN - 0140-7791
DOI - 10.1111/pce.12490
Subject(s) - cell wall , ammonium , chemistry , pectin , hemicellulose , aluminium , biophysics , phytotoxicity , nuclear chemistry , biochemistry , horticulture , cellulose , biology , organic chemistry
Abstract The phytotoxicity of aluminium ( A l) ions can be alleviated by ammonium ( NH 4 + ) in rice and this effect has been attributed to the decreased A l accumulation in the roots. Here, the effects of different nitrogen forms on cell wall properties were compared in two rice cultivars differing in A l tolerance. An in vitro A l‐binding assay revealed that neither NH 4 + nor NO 3 − altered the A l‐binding capacity of cell walls, which were extracted from plants not previously exposed to N sources. However, cell walls extracted from NH 4 + ‐supplied roots displayed lower A l‐binding capacity than those from NO 3 − ‐supplied roots when grown in non‐buffered solutions. Fourier‐transform infrared microspectroscopy analysis revealed that, compared with NO 3 − ‐supplied roots, NH 4 + ‐supplied roots possessed fewer A l‐binding groups (‐ OH and COO ‐) and lower contents of pectin and hemicellulose. However, when grown in pH ‐buffered solutions, these differences in the cell wall properties were not observed. Further analysis showed that the A l‐binding capacity and properties of cell walls were also altered by pHs alone. Taken together, our results indicate that the NH 4 + ‐reduced A l accumulation was attributed to the altered cell wall properties triggered by pH decrease due to NH 4 + uptake rather than direct competition for the cell wall binding sites between Al 3+ and NH 4 + .