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Interactions between Chromium and Sulfur Metabolism in Brassica juncea
Author(s) -
Schiavon Michela,
PilonSmits Elizabeth A.H.,
Wirtz Markus,
Hell Rüdiger,
Malagoli Mario
Publication year - 2008
Publication title -
journal of environmental quality
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.888
H-Index - 171
eISSN - 1537-2537
pISSN - 0047-2425
DOI - 10.2134/jeq2007.0032
Subject(s) - chromate conversion coating , sulfate , brassica , chemistry , chromium , potassium chromate , phytoremediation , sulfur , glutathione , sulfur metabolism , metabolism , environmental chemistry , botany , inorganic chemistry , biochemistry , biology , heavy metals , enzyme , organic chemistry
The effects of chromate on sulfate uptake and assimilation were investigated in the accumulator Brassica juncea (L.) Czern. Seven‐day‐old plants were grown for 2 d under the following combination of sulfate and chromate concentration: (i) no sulfate and no chromate (−S), (ii) no sulfate and 0.2 mmol L −1 chromate (−S +Cr), (iii) 1 mmol L −1 sulfate and no chromate (+S), or (iv) 1 mmol L −1 sulfate and 0.2 mmol L −1 chromate (+S +Cr). Despite the toxic effects exerted by chromate as indicated by altered level of reducing sugars and proteins in leaves, the growth of B. juncea was only weakly reduced by chromate, and no variation in chlorophyll a and b was measured, regardless of S availability. Chromium (Cr) was stored more in roots than in leaves, and the maximum Cr accumulation was measured in −S +Cr plants. The significant decrease of the sulfate uptake rates observed in Cr‐treated plants was accompanied by a repression of the root low‐affinity sulfate transporter ( BjST1 ), suggesting that the transport of chromate in B. juncea may involve sulfate carriers. Once absorbed, chromate induced genes involved in sulfate assimilation (ATP‐sulfurylase: atps6 ; APS‐reductase: apsr2 ; Glutathione synthethase: gsh2 ) and accumulation of cysteine and glutathione, which may suggest that these reduced S compounds play a role in Cr tolerance. Together, our findings indicate that when phytoremediation technologies are used to recover Cr‐contaminated areas, the concentration of sulfate in the plant growth medium must be considered because it may influence the ability of plants to accumulate and tolerate Cr.