Foliar uptake of fluoride (F) resulting from hydrogen fluoride (HF) fumigations was linear with dose (concentration F in μg/m3 × duration of exposure in hours) at F concentrations lower than 17.5 μg/m3. Above this level, duration of exposure was the only important factor and uptake was non-linear with time. Higher leaf N levels resulted in greater F uptake. Production of CO2 was increased more by high F concentration for short periods than by low concentration for longer periods where leaf N was optimal or supraoptimal. Amino nitrogen (AN) levels increased more at low F concentration for longer periods than high concentration for shorter periods. The response patterns were similar at optimal and supraoptimal leaf N. Protein nitrogen (PN) decreased with increasing In HF dose at optimal and very low leaf N levels. Changes in PN and AN were significantly correlated in leaf tissue with optimal, but not in tissues with deficient or supraoptimal N.