Effect of Dowco 290 on RNA Synthesis in Soybean Hypocotyl

10.6165/tai.1977.22.73

Yih-Ming Chen；Chu-Yung Lin

TAIWANIA

22卷1期（1977 / 06 / 01）

73 - 79

英文

Dowco 290 (3,6-dichoropicopicolinic acid), a new product of the Dow Chemical Company U.S.A., is a herbicide. The treatment of intact soybean hypocotyl with this herbicide leads to a very marked aberration in the growth pattern. After Dowco 290 treatment, cell divition in the meristematic zone is inhibited; cell elongation ceases in the meristematic and elongation zones, and radial enlargement of cells occur in the elongation and mature zone. This abnormal proliferation of the mature hypocotyl is associated with the increment of nucleolar size (the diameter was 1.5 to 2.5 mμ for untreated and 4 to 6 mμ for treated nucleoi), however there was no significant alteration in size of the nuclei (about 6×8 to 10mμ). The relative DNA, RNA and protein values are about 1:3:11 for the untreated nuclei. The treatment of Dowco 290 on soybean hypocotyls is also associated with an enhancement of chromatin bound RNA polymerase I activity. The nuclei isolated from Dowco 290 treated tissues showed about five times as much RNA polymerase I activity as the nuclei isolated from untreated tissues. But there was no significant difference in the level of RNA polymerase II activity expressed in the nuclei from untreated and treated tissues. RNA polymerase were solubilized from isolated nuclei and then were fractionated on DEAE-cellulose column, the results show that treated and untreated tissues contained nearly equivalent levels of RNA polymerase I than the untreated nuclei.