The interaction effects of spermidine application and salinity stress in pepper plants

Salinity stress is a limiting factor for plant growth and development and has negative effects on the plant physiological processes. Many compounds are being used to reduce harmful effects of salinity. The purpose of this study was to investigate the effect of spermidine and salt stress on vegetative growth of pepper (Capsicum annuum) plant. In 4 leafy stages, the interactive effects of spermidine solution (0, 1 and 2 mM) and salinity stress (0, 50 and 150 mM NaCl) were studied. The foliar spray of spermidine solution carried out on pepper plants at three different times: (1) simultaneous with the application of NaCl solution to soil, (2) one day before and (3) one day after adding salinity. Treatments were repeated a week later. The effects of spermidine and salinity stress were investigated on root length and some biochemical parameters such as lipid peroxidation, protein and ascorbate content. Data were analyzed with SPSS. The results showed the increase of lipid peroxidation, reduction of protein and total ascorbate contents. In timing 1, the interactive effect of spd2mM and high salinity enhanced root length. Spermidine ameliorated high salinity stress effects on plants. We suggest that spermidine increases resistance to oxidative stress in pepper plants subjected to high salinity stress.