Changes in pigments and secondary metabolites of Artemisia aucheria seedlings in response to in-vitro UV radiation and time

Increase in secondary metabolites content has been attracting interest recently due to their huge economic importance. For example, Artemisia aucheria, which produces artemisinin, has both medicinal and economical importance. The aim of this study was to investigate the effect of single or combination UV radiation as well as sampling time on biochemical-physiological properties of A. aucheria on the increase in secondary metabolites, especially artemisinin. Therefore, a completely randomized factorial design including 7 radiation (no UV, UV-A, UV-B, UV-C, UV- (A + B), UV- (A + C) and UV- (B + C)) and Two different sampling times ( 2 and 24 hours after treatment) was carried out in three replicates. The results indicated that the content of chlorophyll a, b and total chlorophyll decreased in response to all UV radiation conditions except for UV-A. Moreover, the highest decrease of photosynthetic pigments was observed in the UV-(B+C). In addition, the concentration of photosynthetic pigments was reduced through time. In contrast, the content of carotenoids in plants treated with UV-A was increased. Moreover, total flavonoid content was increased about 50% in response to UV-(A+C). Further, the delay in sampling was shown to be associated with an increase in the concentration of flavonoid. Generally, all types of UV radiation, except for UV-C, increased the concentration of artemisinin and most of the other essential oils in both sampling times. Although the highest concentration of artemisinin was observed in the plants treated with UV-(B+C), the usage of UV-B, UV-(A+B) and UV-(A+C) radiation is suggested for increasing the artemisinin content in the short time