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Biogeochemistry of Fluoride in a Plant–Solution System
Author(s) -
Mackowiak C. L.,
Grossl P. R.,
Bugbee B. G.
Publication year - 2003
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/jeq2003.2230
Subject(s) - biogeochemistry , fluoride , environmental science , environmental chemistry , plant science , plant system , chemistry , engineering , inorganic chemistry , agricultural engineering , biology , botany
Fluoride (F − ) pollutants can harm plants and the animals feeding on them. However, it is largely unknown how complexing and chelating agents affect F bioavailability. Two studies were conducted that measured F − bioavailability and uptake by rice ( Oryza sativa L.). In the first study, rice was grown in solution culture (pH 5.0) with 0, 2, or 4 m M F − as KF to compare the interaction of F − with humic acid (HA) and with a conventional chelating agent, N ‐hydroxyethylenthylenediaminetriacetic acid (HEDTA). In the second study, F was supplied at 0, 0.5, 1.0, and 2.0 m M KF with an additional 2 m M F − treatment containing solution Ca at 2× (2 m M Ca) the level used in the first study, to test the effect added Ca had on F − availability and uptake. Total biomass was greatest with HEDTA and F − < 1 m M Leaf and stem F concentrations increased exponentially as solution F − increased linearly, with nearly no F partitioning into the seed. Results suggest that F was taken up as HF 0 while F − uptake was likely restricted. Additionally, F − competed with HA for Ca, thus preventing the formation of Ca–HA flocculents. The addition of soluble Ca resulted in the precipitation of CaF 2 solids on the root surface, as determined by tissue analysis and energy dispersive X‐ray spectroscopy.