EFFECT OF PHENYLALANINE AND LIGHT ON THE GROWTH OF HAIRY ROOTS OF Artemisia tilesii LEDEB

Aim. To analyze the possibility of using phenylalanine of various concentrations and different lighting modes separately and in combination to boost the biomass accumulation and biosynthesis of flavonoids in two lines of Artemisia tilesii Ledeb. hairy roots. Methods. The roots were grown on solidified medium with phenylalanine at high (1mM) and low concentrations (0.05 and 0.1 mM) with lighting (3000 lx, 16 h) and in darkness. After four weeks cultivation, weight gain, flavonoid content and DPPH-scavenging activity were determined according to the standard tests. Results. Roots grown in light were greenish in color, more branched and thick, yet the roots were more elongated after maintenance in the dark. Addition of 1 mM phenylalanine has led to inhibition of growth of all samples. The tolerance to lower concentrations varied among the lines. The flavonoid content for all samples of both lines was higher in the light (up to 3.14 times), regardless of the concentration of phenylalanine. The antioxidant activity was as well higher for the roots grown in light and the values of EC50 correlated with the flavonoid content. Conclusions. Illumination boosted the synthesis of flavonoids and antioxidant activity in all samples of both hairy root lines. The effect of phenylalanine addition on biomass accumulation and flavonoid biosynthesis was line-specific.