Cell and Tissue Journal

Abstract Aim: Potato (Solanum tuberosum L.) is a crop belongs to the Solanaceae family. It is the fourth strategic crops following wheat, rice, and corn. Salicylic acid or orthohydroxybenzoic acid, act as a regulator that can regulate physiological, biochemical and signaling functions in plant metabolic processes. Aim: Salicylic acid as a growth regulator can interact with auxin and gibberellin hormones and effectively induce growth and metabolic processes in potato plants. Potato is one of the most important agricultural plants and in vitro culture can be used as a model in laboratory conditions. The aim of this study is to investigate the effect of salicylic acid on growth indicators and its interaction with other hormones.
Material and method: In this study, potato seedlings with uniform growth were grown on MS culture medium with concentrations of zero, 0.1, 10 and 100 μM salicylic acid. The seedlings were placed in the growth room under light conditions of 16 hours of light and 8 hours of darkness at room temperature. After four weeks, the grown seedlings were used for wet weight, dry weight, shoot and root length, photosynthetic pigments, auxin and gibberellin hormones content were measured. The statistical analysis was performed using SPSS software.
Results: According to the data, growth parameters in the samples treated with salicylic acid showed similar patter. Our results showed that relative water capacity, root and shoot length and pigments under 0.1, 1 and 10 μM significantly increased compared to control samples. While at the concentration of 100 μM, a decreasing trend was observed in the growth parameters and showed a significant decrease compared to the control samples. In this study, the maximum values ​​in all growth parameters were obtained under the concentration of 10 μM salicylic acid. Furthermore, based on the results, the concentration of 0.1 μM salicylic acid had no significant difference on gibberellin hormone content. While the gibberellin hormone content under salicylic acid treatment at concentrations of 1 and 10 μM significantly increased compared to the control sample, and the maximum level was observed at 10 μM. The concentration of 100 μM, unlike the other concentrations, showed a significant difference compared to the control sample with a decreasing trend. Also the results in auxin levels showed a similar pattern with growth parameters and gibberellin hormone. The auxin levels showed a significant increase under the concentrations of 1, 10 and 100 μM compared to the control sample, and the maximum levels were observed at the concentration of 10 μM. However, concentrations of 1 and 10 μM did not show significant differences. Similar to the results of gibberellin hormone, auxin hormone showed a significant difference under the concentration of 100 μM with a decreasing trend compared to the control sample.
 Conclusion: It seems that salicylic acid increased in low concentrations due to the direct effects on the metabolic and enzymatic processes of growth parameters, photosynthetic pigments, and auxin and gibberellin content. On the other hand, at high concentrations, the growth parameters were inhibited due to the high accumulation of reactive oxygen species produced by salicylic acid and the resulting oxidative stress.