Premature onset of mitosis and potentiation of chromosome damage induced by poly- d-lysine in plant cells: evidence for G 2 repair

Abstract

Poly- d-lysine has been reported to induce a triggering of mitosis in plant cells due to a selective stimulatory effect on cells arrested in G 2. Root-tip cells of Allium cepa L. were first exposed to maleic hydrazide (MH) early in the cell cycle and posttreated with different concentrayions of the polycationic agent while in G 2. The result was a dose-dependent potentiation of chromosome damage observed at metaphase without any apparent effect induced by poly- d-lysine itself. The enhancement of the yield of chromosomal aberrations was concomitant with an increase in the frequency of mitosis. In order to test further the stimulatory effect of poly- d-lysine on mitosis, as well as the consequences of a shortening of the time avaible for repair, cells synchronized by protracted treatment with 5-aminouracil (5-AU), which also induces chromosome damage, were allowed to recover in the presence of the polycationic compound. Our data show that a premature arrival at mitosis resulted in an increase in the frequency of damaged cells observed.