Plant cells at different stages in their growth curve differentially activate promutagens.

Mutagenic activity of the promutagens 2-aminofluorene (2AF) and a contaminant of 4-nitro-o-phenylenediamine (NOP-X) was followed in Ames Salmonella strain TA98 following metabolism by cotton and carrot cell suspension cultures using the plant cell/microbe coincubation assay. Both cell lines were capable of activating each chemical. However, activation capacities of the cell lines differed relative to their respective stage of growth when used. For 2AF activation early-log phase cotton cells and mid-log phase carrot cells proved superior while mid-log phase cotton cells and stationary phase carrot cells proved superior for NOP-X activation. These data indicate that the phase of the growth cycle at which plant cells are harvested can significantly affect their promutagen activation potential.