Cell Cycle Population Kinetics of Pea Root Tip Meristems Treated with Propham

Propham (Isopropyl carbanilate) at 10-5 M concentration does not inhibit DNA synthesis nor does it reduce the number of dividing cells. It does, however, induce a number of abnormal mitotic figures. At higher concentrations (10-3 M) propham inhibits DNA, RNA, and protein synthesis as well as stopping entry of cells into mitosis and causing those which divide to be aberrant. DNA and RNA synthesis are not inhibited for approximately 3 hr, while protein synthesis is reduced within 1 hr. The metabolic inhibitory effect of propham is reversible at least in roots treated for 8 hr. The most likely mode of action of propham is the inhibition of certain mitotic specific proteins, or possibly some kind of protein binding function as has been suggested in the literature.