Root cell wall chemistry remodelling enhanced arsenic fixation of a cabbage cultivar.

The low- and high-arsenic (As) transferring cultivars (LTC and HTC) of cabbage showed significant differences in As uptake and distribution. We hypothesise that chemistry of root cell wall matrix plays a critical role. LTC and HTC were treated with As and grown for 60 days. As concentration and distribution at subcellular and cell wall component (pectin, hemicellulose and lignin) levels were determined. Remodelling enzymes (PME and PAL) and functional groups of cell wall were analysed. Results showed that shoot biomass of LTC was not affected by As. Less As was accumulated in shoot of LTC than HTC. LTC allocated more As in root and majority of As was deposited in cell wall. LTC had more hemicellulose 1 (HC1) and lignin, PME and PAL activities. The uronic acid contents of pectin, HC1 or HC2 were all positively (P < 0.05) correlated with As concentrations in each component, respectively. Chemistry of LTC root cell wall was remodelled in terms of changes in porosity, HC and lignin contents, and functional groups, which potentially exerted coupling effects on As entering and deposition. The LTC can restrain As in roots through changing characteristics of root cell wall matrix.
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