Comparison of Atrazine Absorption by Underground Tissues of Several Plant Species

Excised roots of corn (Zea mays L. ‘B73 × Mo 17′) and oat (Avena sativa L. ‘Goodfield’) and potato (Solanum tuberosum L. ‘Kennebec’) tuber slices absorbed 14C-atrazine [2-chloro-4-(ethylamino)-6-(isopropylamino)-s-triazine] in a similar manner during short (1 to 30 min) absorption periods. Within 30 min, atrazine concentrations in tissues and ambient solution were equal. After 24 h of absorption, corn roots contained the most 14C, followed in order by velvetleaf (Abutilon theophrasti Medic.) roots, oat roots, and potato tuber slices. Corn and velvetleaf accumulated 14C to concentrations above the ambient solution. Efflux of 14C was slower for corn than oat, potato, and velvetleaf. Metabolism of atrazine to hydroxyatrazine [2-hydroxy-4-(ethylamino)-6-(isopropylamino)-s-triazine] accounted for accumulation and slow efflux of 14C in corn. These experiments show that initial, rapid absorption of atrazine is comparable, but long-term accumulation differs among these tissues.