Site of Uptake, Movement, and Activity of DCPA

Abstract

Dimethyl tetrachloroterephthalate (DCPA) more severely inhibited growth of roots than shoots of corn (Zea mays L., var. WF9 X B37) and sorghum (Sorghum bicolor (L.) Moench., var. RS 610). Although roots of corn and sorghum were about equally susceptible to DCPA, corn shoots were much more tolerant than sorghum shoots when separately exposed. 14C-DCPA was absorbed by both shoot and root zones of corn and sorghum; however, only limited movement to other plant parts occurred. In contrast to the grass species, cucumber (Cucumis sativus L., var. Wis. SMR-15) roots were tolerant to DCPA. Hypocotyl length was reduced only when the shoot zone was exposed. 14C-DCPA absorbed by the shoot zone moved mainly acropetally. Root-absorbed 14C-DCPA tended to be accumulated there with only limited movement upward. Uptake by the hypocotyl of cucumber and movement of 14C-DCPA to foliage after emergence occurred readily, and pretreatment with unlabeled DCPA before emergence enhanced uptake.