Enhanced Deoxyribonucleic Acid Polymerase Activity of Chromatin from Soybean Hypocotyls Treated with 2,4-Dichlorophenoxyacetic Acid

Chromatin isolated from soybean (Glycine max L., var. Wayne) hypocotyls was capable of catalyzing the polymerization of labeled deoxyribonucleoside triphosphate in the presence of the three other deoxyribonucleoside triphosphates into a trichloroacetic acid-insoluble product. This product was insensitive to base hydrolysis and ribonuclease, but was sensitive to acid hydrolysis and deoxyribonuclease. Chromatin-DNA polymerase required Mg(2+) and all four deoxyribonucleoside triphosphates for maximal activity. Inorganic pyrophosphate and actinomycin D inhibited the polymerase activity, but 2, 4-dichlorophenoxyacetic acid had no effect in vitro. Chromatin from plants previously treated with 2, 4-dichlorophenoxyacetic acid supported a greater level of DNA synthesis than did chromatin from untreated plants.