Treatment with spermidine protects chrysanthemum seedlings against salinity stress damage

•Salt stress promotes metabolism of endogenous PA in chrysanthemum.•1.5 mM Spd would be an effective concentration to alleviate salt stress.•Spd alleviates salinity injury via increasing photosynthesis, ROS scavenging ability.•Spd alleviates salinity injury via regulating ionic balance and osmotic potential.•Protective role of Spd was pronounced in sensitive cultivar than in tolerant one.

Salinity-stressed plants of salinity sensitive (‘Qx096’) and tolerant (‘Qx097’) chrysanthemum cultivar were treated with a range of concentrations of spermidine (Spd). Plant performance, as indicated by various parameters associated with growth, was improved by the treatment, as was the tissue content of soluble protein and proline. The extent of both Na+ accumulation and K+ loss was reduced. Activity levels of the stress-related enzymes SOD, POD, APX and CAT were significantly increased and the production of malondialdehyde (MDA) decreased. The suggestion was that treatment with 1.5 mM Spd would be an effective means alleviating salinity-stress induced injury through its positive effect on photosynthetic efficiency, reactive oxygen species scavenging ability and the control of ionic balance and osmotic potential. Its protective capacity was more apparent in ‘Qx096’ than in ‘Qx097’.