vinifera) Grapevines under NaCl Stress

Soil salinity affects the growth and development of grapevines; however exogenous calcium application can mitigate the growth inhibition effects of salt stress to a certain extent.Therefore, this study was conducted to evaluate the effects of exogenous CaCl 2 and inhibitors {LaCl 3 , CPZ (chlorpromazine), heparin, and EB (eosin)} on sand-cultured annual self-rooted Tamina grape seedlings in the presence of 200 mmol L -1 NaCl.Results showed that salt stress inhibited the shoot length and total biomass of plants by 14.1 and 17.5%, respectively compared with control plants.Salt stress obviously increased the electrolyte leakage of roots and leaves and O 2 -production rate and H 2 O 2 contents in grapevine leaves while it decreased the activity of superoxide dismutase (SOD), catalase (CAT), peroxidase (POD), ascorbate peroxidase (APX) and glutathione reductase (GR) after ten days of treatment.In the NaCl + CaCl 2 treatment group, not only electrolyte leakage of roots and leaves was decreased but O 2 -production rate and H 2 O 2 contents in the leaves were also decreased.The activity of antioxidant enzymes was greater in NaCl + CaCl 2 treatment group than NaCl treatment group.CaCl 2 + inhibitor treatment decreased the activity of POD, APX and GR compared with their activity in CaCl 2 treatment under NaCl stress, but CaCl 2 + inhibitor treatment increased the H 2 O 2 content in the leaves and the electrolyte leakage of the roots and leaves.Ca 2+ showed influx transport in grapevine roots, but the net flow rate was significantly lower than control after one day of 200 mmol L -1 NaCl treatment.The net flow rate in CaCl 2 treatment recovered to the level of control, and in CaCl 2 + LaCl 3 treatment was lower than CaCl 2 treatment.In conclusion, exogenous CaCl 2 improved the salinity tolerance of grapevines by increasing the activities of antioxidant enzymes, and it also affected Ca 2+ transport through both the Ca 2+ channel and Ca 2+ external flow system.