The effect of salicylic acid, methyl jasmonate and NaCl stimulants on biochemical compounds of stevia’s callus in solid and liquid media

Using stimulants is an efficient way to increase the production of secondary metabolites of medicinal plants under in vivo and in vitro conditions. The present study aimed to investigate the effect of NaCl (0 and 50 mM), salicylic acid, and methyl jasmonate (each in 0 and 100 μM) in solid and liquid culture media on the biochemical properties and phenylalanine ammonia-lyase (PAL) activity of stevia callus under in vitro conditions. This study was conducted in a completely randomized design with a two-factor factorial arrangement in four replications. The stimuli used, culture medium and their interactions had a significant effect on the measured traits. The highest amount of phenol and flavonoid production was observed in salicylic acid 100 + salinity 50 and salinity 50 treatments in solid culture medium. Treatments including salinity 50, salicylic acid 100 + salinity 50 and methyl jasmonate 100 + salinity 50 in the solid medium increased PAL enzyme activity compared to other treatments. PAL enzyme, phenol and flavonoid were positively correlated each other. The 50 mM salinity treatment also increased proline amino acid content. Therefore, in order to improve the production of secondary compounds such as phenol, flavonoids and also PAL enzyme activity in stevia, a combination of salicylic acid (100 μM) and salinity (50 mM) is recommended under solid culture medium conditions.