Influence of lead on atrazine uptake by rice (Oryza sativa L.) seedlings from nutrient solution.
BACKGROUND
Atrazine is a widely used herbicide, and its persistence in soil and water causes environmental concerns. In the past, plant uptake processes are mainly investigated for single contaminants. However, in many cases, contaminants co-exist in environmental matrix, such as soil, and plant uptake of one contaminant may be influenced by its co-existing ones.


METHODS
The uptake of atrazine by rice seedlings (Oryza sativa L.) from nutrient solution through the roots was investigated in a solution culture, over an exposure period of 4 weeks. Atrazine accumulation in plant tissues was determined by gas chromatography, and lead was determined using atomic absorption spectrometry.


CONCLUSIONS
With different ratios of atrazine and Pb2+ concentrations in solution, the observed atrazine concentrations in shoots and roots varied significantly. In atrazine-Pb2+ mixture systems, the added Pb2+ either increased or decreased the concentrations or BCFs of atrazine in seedlings (relative to those without Pb2+), depending on the atrazine-Pb2+ ratio in nutrient solution. The enhanced atrazine uptake results presumably from atrazine-Pb2+ complex formation. The reduced atrazine uptake, which occurred mainly at high atrazine concentrations, is attributed to atrazine toxicity that inhibited seedling growth and transpiration.


CONCLUSIONS
The formation of atrazine-Pb2+ complex both in the solution and within plant tissues may affect the accumulation of both contaminants by rice plants.
Su
Yu-Hong
YH
Research Center for Eco-environmental Sciences, Chinese Academy of Sciences, 18 Shuangqing Road, Beijing 100085, China.
Zhu
Yong-Guan
YG
D001280:Atrazine / Q000032:analysis / Q000378:metabolism*; D001692:Biological Transport / Q000187:drug effects; D018533:Biomass; D006540:Herbicides / Q000032:analysis / Q000378:metabolism*; D007854:Lead / Q000032:analysis / Q000494:pharmacology*; D012275:Oryza / Q000187:drug effects* / Q000378:metabolism; D018517:Plant Roots / Q000187:drug effects / Q000378:metabolism; D018520:Plant Shoots / Q000187:drug effects / Q000378:metabolism; D036226:Seedlings / Q000187:drug effects / Q000378:metabolism; D012996:Solutions
D006540:Herbicides; D012996:Solutions; D007854:Lead; D001280:Atrazine