Investigating physiological responses of Wild Rocket subjected to artificial Ultraviolet B irradiation

Utilization of ultraviolet-B radiation (UV-B) is a way to encourage the accumulation of phytochemicals such as glucosinolates, carotenoids, phenolics and flavonoids in plants. In the current research, UV-B treatments were performed, as a possible elicitation strategy to promote the secondary metabolites accumulation in wild rocket (Diplotaxis tenuifolia (L.) DC). After performing the destructive analysis, it has been found that the concentration of chlorophyl a and b as well as carotenoids decreased in response to the UV-B stress. Thiobarbituric acid reactive substances (TBARS) assay has been performed to investigate the membranes damage caused by the UV-B radiation. The analyses confirmed that the highest UV-B tested dose induced the greater damage. Interestingly, an increase of phenolic index, and an accumulation of anthocyanins and glucosinolates has been recorded under the successive exposure of varying UV-B doses. The total sugars, reducing sugars and sucrose buildup were also remarkable. Non-destructive analysis revealed a decline in the overall performance of the UV-B treated plants as well as the maximum quantum efficiency of photosystem II. A decrease in the chlorophyll estimates while an enhanced flavanols and anthocyanins were observed through non-destructive readings. Results of this study not only provided a feasible UV-B dose selection and supplementation for the wild rocket but also the understanding about enhanced phytochemical accumulation in plants against UV-B stress.