Figure 4.

Arginine and proline utilization in amino acid-fed rice cells. Suspension cultured cells of rice (cv Loto) were supplied with different concentrations of either proline (A,C,E) or arginine (B,D,F). At increasing time after the addition of the exogenous amino acid, its residual level in the medium was determined (A,B). Cells from the same samples were harvested and washed thoroughly before intracellular levels of total amino acid (C,D), free proline (E) and free arginine (F) were determined on a fresh weight basis. All treatments were carried out in triplicate, and means ± SE are reported. Virtually overlapping patterns were obtained with cell cultures of the cv Vialone nano.