Aspen cell cultures were fed 5 mM salicyl alcohol at the early exponential phase (5 days after subculture). Cells were harvested from fed (SL) or unfed (C) cells after 48 hours. Gene expression changes were analyzed using a custom 7K aspen EST array. RNA was extracted from 3 independent control (C) and 3 salicyl alcohol-fed (SL) samples, and one control and one treated sample were randomly paired for hybridization (3 biological replicates). Dye-swap hybridizations were carried out for each pair of samples.