Effect of La(NO_3)_3 on the Cold Tolerance of Caryota mitis Lour.

The effects of La(NO3)3 on cold tolerance of Caryota mitis seedlings were conducted by several physiological indices.The foliage of Caryota mitis was sprayed with 0,100,350 and 500 mg/L La(NO3)3 solution.The changes of activities of SOD,POD,and the contents of MDA,proline,soluble protein,chlorophyll and chlorophyll a/b of Caryota mitis were studied under different temperature.All the above-mentioned physiological indices varied with different solution.The results of the comprehensive evaluation indices of the fuzzy membership functions system under the 25 ℃ were 0.41,0.46,0.70 and 0.50,respectively.It was shown that spraying leaves with different concentrations of La(NO3)3 could enhance the cold tolerance of Caryota mitis seedlings,and the appropriate concentration was 350 mg/L.