Trifluralin Uptake and its Effect on ABA Content in Growing Maize and Pea Roots

Summary Some characteristics of the herbicide trifluralin (TF), applied to roots of Zea mays and Pisum sativum , are studied: its uptake and effects on growth and free ABA content. Maize roots are sensitive to TF (5 μM) since their elongation is slowed down and their diameter strongly increased whereas pea roots are not affected by TF at this concentration. 14 C-TF uptake was higher in maize than in pea roots, but only in the elongation zone. ABA level — which was found to be involved in TF action (Locher and Pilet, 1994) — is about 10 times higher in pea than in maize roots. Moreover, applied TF induced an increase of ABA content in maize roots. TF sensitivity and tolerance for maize and pea roots are discussed in relation to TF uptake and endogenous ABA.