[en] The availability of Np(V) for absorption by plants and its subsequent transport and fate are described. Plant uptake of Np from solutions containing 7 x 10^-7 to 473 μg Np/ml is proportional to concentration, exhibiting some saturation at higher concentrations. Soil studies using Np concentrations of 5.2 x 10^-7 to 4.1 μg/g soil show CR values to be constant at approx. 2 at soil concentrations below 4 x 10^-4 μg/g, and increase to 12 at higher soil levels. Soil/plant CR values vary with plant species and range from 0.5 to 4; seed concentrations are a factor of 10 lower than vegetative tissues. Fractionation of plant tissues show Np to be substantially more soluble than Pu, with approx. 50% of the soluble Np being associated with plant ligands of < 5000 MW. 6 references, 5 figures, 1 table