Growth, graviresponsiveness and abscisic-acid content of Zea mays seedlings treated with fluridone.
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) microgram ABA g-1 FW; detipped roots, 0.260 +/- 0.039 +/- microgram 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.
Moore
R
R
Department of Biology, Baylor University, Waco, TX 76798, USA.
Smith
J D
JD
D000040:Abscisic Acid / Q000037:antagonists & inhibitors / Q000378:metabolism*; D002338:Carotenoids / Q000037:antagonists & inhibitors; D018522:Gravitropism / Q000187:drug effects* / Q000502:physiology; D018466:Gravity Sensing / Q000502:physiology; D006540:Herbicides / Q000494:pharmacology; D018518:Plant Root Cap / Q000187:drug effects / Q000254:growth & development / Q000378:metabolism; D011728:Pyridones / Q000494:pharmacology*; D003313:Zea mays / Q000187:drug effects* / Q000254:growth & development / Q000378:metabolism*
D006540:Herbicides; D011728:Pyridones; D002338:Carotenoids; C013351:fluridone; D000040:Abscisic Acid