Factors affecting absorption, transport, and form of plutonium in plants

The absorption of Pu by plants was related primarily to differences in soil properties and to the presence of natural and synthetic organic ligands that partially stabilized Pu against hydrolysis in soil. Plant/soil concentration ratios (CR) were also affected by a series of secondary processes related to plant growth rate and production of biomass. The valence state of Pu added to soil did not affect CR values due to reduction of Pu(VI) to Pu(IV). The Pu was transported in plant xylem fluid to aerial leaf tissue as Pu(IV) organic acid complexes. Variables affecting the chemical form of Pu in plants after uptake included plant age, plant species, and the presence of nutrient elements (especially Fe, Zn, and Cu) that competed for reaction sites on plant organic ligands. Test plants used were alfalfa, peas, soybeans, squash, and bushbeans