Uranium accumulation of crop plants enhanced by citric acid.
Citric acid was applied to soil to enhance U accumulation in four crop plants. While the highest enhanced U accumulation of aboveground tissues (a.c. 2000 mg kg(-1) dry weight) occurred in the leaves of Indian mustard (Brassica juncea), the highest enhanced U accumulation of roots (a.c. 3500 mg kg(-1) dry weight) occurred in canola (Brassica napus var. napus). Uranium translocation among tissues of test plants is in the relation of roots>shoots congruent with leaves. The flowers of sunflower (Helianthus annuus) contained similar or higher U concentrations than those found in shoots, but concentrations in seeds are close to zero. In conclusion, Indian mustard is recommended as a potential species for phytoextraction for U-contaminated soil due to its high U accumulation of aboveground biomass (a.c. 2200 microg per plant). There is no evidence that two types of soils cause a significant difference of the enhanced U accumulation (p<0.05). Results, however, indicate that additional citric acid may result in downward U migration that may contaminate groundwater. Speciation of U that is taken up by plants is also discussed in the end.
Chang
Peichun
P
UNU and GIST Joint Programme on Science and Technology for Sustainability, International Environmental Research Center, Gwangju 500-712, South Korea.
Kim
Kyoung-Woong
KW
Yoshida
Satoshi
S
Kim
Soo-Young
SY
D019343:Citric Acid / Q000737:chemistry*; D018556:Crops, Agricultural / Q000378:metabolism*; D004787:Environmental Pollution / Q000517:prevention & control*; D007723:Korea; D013058:Mass Spectrometry; D012987:Soil / Q000032:analysis*; D014501:Uranium / Q000032:analysis* / Q000493:pharmacokinetics*
D012987:Soil; D019343:Citric Acid; D014501:Uranium