Abstract:

Five-leaf stage seedlings of the ornamental Lupins cultivar ‘Minaretie’ were studied under high-temperature stress of 30℃-45℃ after spraying 200 μmol/L salicylic acid. Leaf superoxide dismutase activity, peroxidase activity, malondialdehyde content, soluble protein and sugar content were measured in order to clarify the responsive mechanism. The results showed that salicylic acid pretreatment effectively increased superoxide dismutase and peroxidase activity, osmoregulation substance content of soluble protein and sugar, but restrained the increase of malondialdehyde content in leaf. Antioxidant enzyme activity and osmoregulation substance content increased with temperature. When the temperature was out of 40℃, they decreased. Peroxidase activity in leaf was sensitived to the treatment of salicylic acid and it can be used to an indicator to measure high-temperature resistance. Thus, the exogenous salicylic acid could reduce high-temperature stress to hurt ornamental Lupins seedlings by improving antioxidation ability and osmoregulation substance content, protecting structure and function of cell membrance.