La(NO_3)_3 and cold tolerance with Caryota urens seedlings

The study was performed to investigate the effects of La(NO3)3 on the cold tolerance of Caryota urens seedlings.Effects of La(NO3)3 were tested by spraying the foliage of C.urens with 0,100,350 and 500 mg·L-1 La(NO3)3 solution.Then,physiological indices,including activity of superoxide dismutase(SOD) and peroxidase(POD) as well as the content of malondialdehyde(MDA),proline,soluble protein,chlorophyll,and chlorophyll a/b,were determined after treated in 25 ℃(1),5 ℃,and 25 ℃(2) for 24 h respectively in turn.It was indicated that all the above-mentioned physiological indices varied with different concentrations of La(NO3)3.Results of the fuzzy membership functions comprehensive evaluation for different La(NO3)3 solution at 25 ℃(2) were 0.39 for 0 mg·L-1,0.34 for 100 mg·L-1,0.85 for 350 mg·L-1,and 0.76 for 500 mg·L-1.It was concluded that spraying leaves with different concentrations of La(NO3)3 could affect the cold tolerance of C.urens seedlings with the most effective being 350 mg·L-1.