A comparison of effects of several herbicides on photoautotrophic, photomixotrophic and heterotrophic cultured tobacco cells and seedlings.

The effects of herbicides with different primary modes of action were examined on the growth of photoautotrophic, photomixotrophic, and heterotrophic cultures of tobacco cells. These responses were compared with those of tobacco seedlings to the same herbicides. Herbicides, which primarily inhibit or disturb photosynthetic processes, suppressed the growth of photoautotrophic cells most strongly, as compared to photomixotrophic and heterotrophic cells (atrazine, diuron, paraquat). Herbicides having a primary mode of action other than the inhibition of photosynthetic processes, suppressed the growth of all types of cultured cells at similar concentrations (2,4-D, diphenamid, glyphosate, dinoseb, sodium chlorate, bialaphos, DTP), but the photoautotrophic cells were still the most sensitive to all kinds of herbicides except sodium chlorate. Furthermore, photoautotrophic cells responded to most of the herbicides as did the seedlings, with the exception of glyphosate and diphenamid. The possibility of photoautotrophically cultured cells as a model system to study the effects of herbicides are discussed.