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Chemical fractions and phytoavailability of copper to rape grown in the polluted paddy soil
Yang, H. F.; Wang, Y. B. & Huang, Y. J.
Abstract
This paper focuses on the phytoaccumulation
and translocation of copper (Cu) in rape grown in the Cupolluted
paddy soil. Pot experiments were conducted in
greenhouse conditions to examine the Cu availability and
uptake by rape in a paddy soil. The soil was spiked with
different concentrations of Cu (0, 100, 300, 500 and
1,000 mg kg-1 soil, added as CuSO4) to simulate soil Cu
contamination. After 8 months of growth, plant shoots,
stems, pod shells and rapeseeds were harvested for analysis.
The concentrations of Cu in the roots and aerial parts
of the rape and available Cu in soils were then extracted
and determined. Chemical fractions of Cu in the paddy soil
of rape were also investigated by sequential extraction
techniques. The findings showed that Cu in the clean paddy
soil was mainly distributed in residual fractions. However,
the most drastic increase was observed in Fe–Mn oxidesbound
fractions and organic-bound fractions with increasing
soil Cu concentrations. Exchangeable fractions played
a more important role than other fractions in controlling the
mobility and phytoavailability of Cu. Rape growth was
stimulated by low concentrations of Cu, but inhibited by
high concentrations. Compares to the aerial parts, the roots
were more sensitive to Cu toxicity. The correlation analysis
showed that Cu in exchangeable fractions made the
greatest contribution on the accumulation of Cu in rapes.
The factor analysis results showed that the exchangeable
fractions in roots can be indicator of Cu availability.
Meanwhile, the bio-concentration factors and the translocation
factors of Cu in rape were determined and the results
showed that Cu had lower accumulation in the edible parts
of the rape.
Keywords
Brassica napus L.; Chemical fractionation; Copper accumulation; Factor analysis; Phytoaccumulation
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