title: Growth, graviresponsiveness and abscisic-acid content of Zea mays seedlings treated with Fluridone.
abstract: Ten-d-old seedlings of Zea mays L. cv. Tx 5855 treated with 1-methyl-3-phenyl-5-(3-[trifluoromethyl]phenyl)-4-(1H)-pyridinone (Fluridone) were analyzed for abscisic acid (ABA) content using high-performance liquid chromatography with an analysis sensitivity of 2.5 ng ABA g(-1) fresh weight (FW). Seedlings were divided into three portions: leaves, detipped roots, and root tips (terminal 1.5 mm). Control plants (water treatment only; no Fluridone) were characterized by the following amounts of ABA: leaves, 0.114±0.024 (standard deviation) μg ABA g(-1) FW; detipped roots, 0.260±0.039±μg ABA g(-1) FW; root tips, no ABA detected. We did not detect any ABA in tissues of Fluridone-treated plants. Primary roots of treated and untreated seedlings were strongly graviresponsive, with no significant differences between the curvatures or the growth rates of primary roots of Fluridone-treated and control seedlings. These results indicate that 1) Fluridone completely inhibits ABA synthesis, and 2) ABA is not necessary for positive gravitropism by primary roots of Zea mays.
authors.affiliation: Department of Biology, Baylor University, 76798, Waco, TX, USA.
authors.forename: R
authors.initials: R
authors.lastname: Moore
authors.forename: J D
authors.initials: JD
authors.lastname: Smith