Effects of NaCl and KCl alone or in combination with CaCl₂, Na₂SO₄ or K₂SO₄ on fast chlorophyll a (Chl a) fluorescence kinetics of mung bean (Vigna radiata L.) and Brassica (Brassica juncea Coss.) were studied. The concentrations of NaCl and KCl used were 100 mmol/L to 300 mmol/L and the concentration of CaCl₂ was 5 mmol/L. Na₂SO₄ and K₂SO₄ used were in the range of 50 to 200 mmol/L. Salt treatments were given to 6 d old seedlings and Chl a measurements were taken subsequently for 3 d after the salt treatment. The fast Chl a fluorescence kinetics of mung bean and Brassica seedlings showed no significant change within 3 d of experiments without the addition of salts/ions. The salt/ion treatments significantly affected the Chl a fluorescence kinetics. The initial Chl a fluorescence level (F₀) increased after 3 d with NaCl, which was enhanced by the addition of CaCl₂. KCl and Na₂SO₄ or K₂SO₄ induced an increase in F₀ after 1 d of salt treatments. CaCl₂ alone and with NaCl or KCl enhanced F_M after 1 d of treatment. KCl alone increased F_M values after 1 d. However, the maximum Chl a fluorescence level (F_M), quantum yield of the primary photochemistry of PS II (ϕ_Po), quantum yield of electron transport beyond Q_A⁻ (ϕ_Eo), efficiency that a trapped electron can move further ahead of Q_A⁻ (ψ_o) and flux ratio of electron transport (E_To/RC) decreased significantly with NaCl treatments after 3 d of treatment. CaCl₂ ameliorated these effects. ABS/RC and DI₀/RC was enhanced several folds by NaCl treatments and CaCl₂ augmented these effects. Other salts and their combinations also showed enhancement in DI₀/RC. However, Na salts showed amplified effects at equimolar concentrations compared to K salts. The most prominent difference in the susceptibility of a system or genotype to different salts or ions is due to the changes of the abundance of active reaction centers per leaf cross-section (RC₀/CS₀).