Effects of Exogenous Calcium on Datura Seed Germination under Drought Stress

With polyethylene glycol(PEG-6000),of 0%(CK),5%,10%,15%,25%used to simulate drought stress,and CaCl2 concentration 0(CK),of 15,20,25 and 30mmol/L as ion gradient of exogenous calcium,the effects of drought,exogenous calcium and the interaction between the two on the Datura seed germination,so as to explore the optimal application amount of exogenous calcium to ease the suppression of drought stress on Datura seed germination.The results showed that the germination rate,germination potential and germination index of the Datura seeds were significantly lower than those of the control group.Under the normal moisture condition,exogenous calcium of moderate and low concentration had no significant effect on the Datura seed germination,while that of high concentration showed an inhibitory effect on the seed germination.Under drought stress,with the increasing concentration of exogenous calcium,the three indicators of Datura seeds showed a trend of increasing first and then decreasing.When the exogenous calcium had the concentration of 20 mmol/L,all the indicators of seed germination reached the maximum value,while showed a downward trend when exogenous calcium concentration was 25-30 mmol/L,and even increasingly sharp with drought intensifying.Therefore,in the production and utilization of Datura,20 mmol/L of exogenous calcium can be used to soak seeds before sowing to improve the emergence rate under low and moderate drought conditions.