The effect of seed treatment with salicylic acid (SA) on the carbonic anhydrase (CA) activity, photosynthesis rate, stomatal conductance, and pigment content in wheat leaves was studied at an optimal zinc content (2 μM) and zinc excess (1500 μM). It was shown for the first time that the CA activity and stomatal conductance increased upon seed treatment with SA at the optimal zinc content as compared with untreated plants, while the photosynthesis rate was not affected. When zinc was in excess in the root zone, seed treatment with SA decreased the CA activity to a greater extent, but the photosynthesis rate was higher than in untreated plants, apparently due to an increase in the contents of chlorophylls and carotenoids and stomatal conductivity. It was concluded that SA is involved in the protective and adaptive responses of wheat plants to excess environmental zinc along with other nonhormonal factors and hormones.