In the present work, by using BY-2 tobacco suspension cells, the effect of the extracellular ATP on the cell death and respiration inhibition induced by NaCl stress was studied. The results showed that with the increase of the concentrations of NaCl (from 50 to 400 mmol/L)，the level of cell death was increased, while the levels of extracellular ATP and respiratory O2 uptake were decreased. The suspension cells subjected to 200 mmol/L NaCl stress were usded to study the effects of the extracellular ATP on the cell death induced by NaCl stress. Compared with the cells under NaCl stress (200 mmol/L), the NaCl-stressed cells with addition of exogenous ATP (20 μmol/L) had lower cell death and higher contents of both extracellular ATP and the respiratory O2 uptake. These results suggest that the cell death and respiration inhibition induced by NaCl stress are related to the change of extracellular ATP, and extracellular ATP can function in mediating the NaCl-induced cell death and respiration inhibition.
