OBJECTIVETo study the effect of exogenous Ca2+ on protective infection of Pinellia ternata and accumulation of major components under high temperature stress.

METHODThe soilless cultivation experiment was applied, stress resistance index of P. ternata leaves, statistics the rate of lodge P. ternata,the content of oxalate in different places in the plant, the content of total alkaloids, total organic acids and glucosine in P. ternata tubers were measured based on different concentrations of exogenous Ca2+.

RESULTThe test results showed that, at lower concentrations of Ca2+ treatments, the rate of lodge P. ternata was higher than that of the others. With Ca2+ concentration increasing, activities of SOD and POD initially increased and then decreased, however, proline level tended to be down then up. Soluble oxalic acid content was lower than the content of unhandled treatment in P. ternata leaves and tubers; with Ca2+ concentration increasing, soluble oxalic acidl content and yield showed a tendency of decrease after increase in the leaves and tubers. Compared with other treatments, spraying 400 mg x L(-1) Ca2+ significantly enhanced the accumulation of total alkaloid and guanosine in P. ternata tubers. At Lower concentrations of Ca2+, the content of total free organic acid was higher in the tuber.

CONCLUSIONWith the treatment of Ca2+ the capacity of heat resistance was improved in P. ternata plants, the rate of lodge P. ternata was postponed, growing period was extended and corresponding production has increased by spraying exogenous Ca2+.