UV and Laser Diode as a Source of Flavonoids Stimulation Production in Marigold Calendula officinalis

Calendula officinalis is an important herbal plant as it is a source of value compounds, and it is a convenient model for plant micro propagation. The aim of this study was micro propagation of C. Officinalis and evaluation of the efficiency of Laser diode and UV-C irradiation, in the stimulation of flavonoids biosynthesis and accumulation in vitro culture. BA 1.5mg.L −1 had a significant effect on the number of explants, reached 6.7 shoots.explant −1 . While the nodes, BA 1.mg.L −1 had the highest effect on the average shoot length explants, which increased to 2.9 cm. UV exposure resulted in an increase in the shoots and number of leaves of explants treated by BA 1.5 mg/L. After 60 min of UV exposure, the accumulation of flavonoids Rutin in marigold increased to 343.458 ppm /g compared to the control 21.735 ppm/g. Galic acid decreased to 0.122 ppm/ g. The laser diode caused more changes in flavonoids, the Rutin was 4.742ppm /g while Gallic acid reached 50.825 ppm/g, about 5-fold. This stimulation by laser can act as an actor to stimulate one compound and reduce the others, it seems the plant’s secondary compounds compete with each other’s and sometimes with the same type, like Rutin and Galic acid.