The influence of age of red spruce (Picearubens Sarg.) cell suspensions on aluminum (Al) effects was studied by adding AlCl3 (0.2, 0.5, and 1.0 mM) to the media on each day of a 7-day culture period and analyzing for changes in total cell mass, polyamines, arginine decarboxylase activity, and inorganic ions after 24 h of incubation. The effective concentrations of monomeric Al in the medium were found to be approximately 0.09, 0.23, and 0.48 mM, respectively. All levels of Al inhibited growth and increased cellular putrescine levels and arginine decarboxylase activity. Spermidine and spermine levels were either slightly elevated or not affected by Al. Cellular content of Ca, Mg, Mn, and K decreased, while Al and P increased in Al-treated cells. Aluminum effects, in general, were dose dependent. Since the response to 24 h incubation with Al was generally independent of culture age, 3-day-old cultures were selected to further study short- and long-term (4 h to 11 days) effects of Al. Cellular putrescine levels remained elevated in the Al-treated cells for the entire duration of the experiment. There was a sharp dose-dependent increase in spermine levels by the 7th day of incubation. After the initial decrease, Al treatments for longer than 2 to 4 days did not cause consistent effects on Ca, Mn, and Mg levels. Potassium decreased and P and Al increased in a dose-dependent manner over the 11-day culture period.