Figure 2.

Effect of copper stress and DPI application on the cell cycle re-entry of stationary phase cultured plant cells. (A) The amount and activity of the cell cycle-regulatory CDKA/BMs kinase in 11-day old suspension-cultured alfalfa cells following subculture into fresh medium supplemented with copper (30 µM CuSO4, Cu), DPI (1 µM, DPI), their combination (Cu + DPI), or nothing (Contr.). The upper histogram shows the densitometry values of the CDK activity (as in vitro histone H1 phosphorylation activity of immunoprecipitated CDKA/BMs protein complexes also shown in the upper lane as an autoradiogram). The CDKA/BMs protein amount is determined by Western analysis (lower lane). (B) Growth of the control and treated cells as shown by fresh weight four days after subculture. The initial cell density is shown as a dashed line.