The impact of salt stress on growth and some biochemical parameters of Echinaceae purpurea L.

Echinaceae prupurea, belongs to the Asteraceae family and is a perennial herb with different medicinal properties. The aim of the present study was to investigate the effect of salt stress on growth and some important biochemical parameters of this plant. For this purpose, Echinaceae prupurea plantlets were grown in Hoagland medium supplemented with different concentrations of NaCl (including 10, 50, 100, 300, and 500 mM) for 20 days. The experiment was carried out in a completely randomized design with five replications. The obtained result showed that the effects of different concentrations of NaCl were not significant on shoot dry weights. But root fresh and dry weights exhibited a significant increasing trend by 25 mM NaCl treatment. Meanwhile, the current data showed that increasing salt concentration in the medium caused an increase and decrease in soluble sugar level in shoots and roots, respectively. While salt stress did not show any significant effect on catalase enzyme activity, peroxidase enzyme activity was significantly increased by 75 mM NaCl treatment, in both shoots and roots. On the other hands, salinity treatment significantly decreased and increased total phenol levels in shoots and roots, respectively. The data from HPLC analysis demonstrated that the highest level of cichoric acid (1.3 mg/g dry weight) was observed in roots of control samples. While NaCl at the level of 25 and 50 mM concentrations did not show any significant effect on cichoric acid amount, it was significantly decreased by 75 mMN aCl treatment. Moreover, 50 mM NaCl treatment enhanced 2 and 5 fold caffeic acid (precursor of cichoric acid) and chlorogenic acid level in root organ, respectively. It seems salt stress can increase the important medicinal secondary metabolites of Echinaceae purpurea.