Uptake and Translocation of Alachlor in Soybean and Wheat

Translocation of alachlor [2-chloro-2′,6′-diethyl-N-(methoxymethyl) acetanilide] in soybean [Glycine max (L.) Merrill] and wheat (Triticum aestivum L.) was primarily apoplastic with greater uptake and translocation in wheat (susceptible) than in soybean (resistant). Root-applied 14C-alachlor translocated throughout both plants. Root uptake was greater for wheat than for soybean and older leaves accumulated more than did younger actively growing tissue in both species. Foliar applications to the primary leaves of soybean and wheat resulted in some apoplastic translocation within the treated leaf of wheat but only slight translocation in soybean. Absorption of 14C-alachlor reached equilibrium at 4 hr by excised wheat root tissue, while absorption continued after 32 hr in excised coleoptile and leaf tissue. Absorption of alachlor by leaf and coleoptile tissue was greater in light than in the dark.