DPX-3778 is the triethanolamine salt of 3-(p-chlorophenyl)-6-methoxy-s-triazine-2,4(1H,3H) dione, at concentrations of 0.124-2.48 μM enhanced ca. 4-5-fold the proliferation of tobacco (Nicotiana tabacum L. cv. Wisconsin 38) callus cultured in the presence of indole-3-acetic acid and kinetin, and retarded its senescence.