Anethum graveolens is an annual herb in the celery family Apiaceae. The experiment was carried out in a factorial design with two factors include salinity, which was applied to the root medium as NaCl (0 and 10 ds/m) and nutrition as sodium silicate (0 and 1.5 mM), and selenate (0, 5 μM). Supplementary Si or Se ameliorated the negative effects of salinity on plant dry matter and chlorophyll content. Application of Si or Se decreased Na+ concentration and increased K+ concentration in roots and shoots of dill plants. Salinity imposed oxidative stress and leaded to increase malondialdehyde (MDA) concentration. Under saline condition, addition of Si/Se significantly increased the activities of superoxide dismutase (SOD) and catalase (CAT) in salt-stressed plant when compared with plant subjected to salinity alone. Our results revealed that improvement in growth of salt stressed plants under the influence of Si and Se may be due to the improved ion balance, antioxidant enzymes activities and osmotic adjustment. These trace elements had negative effect on growth under non-saline conditions. Therefore, application of these trace elements (especially Silicon) under saline condition could be a better strategy for maintaining the crop productivity in these regions.
