Fig. 4.

Inhibition of photocurrent generation by atrazine, terbutryn and stigmatellin. Percentage inhibition is the maximum photocurrent density during 30 s illumination relative to that obtained prior to addition of the first aliquot of inhibitor. Each data point is an average from three titrations on three separate cells, with error bars showing the standard error. Solid lines show fits to a logistic function to determine the IC₅₀ (see text).