Morphogenic and biochemical variations under different spectral lights in callus cultures of Artemisia absinthium L.

• Effect of various monochromatic lights on callus of Artemisia absinthium was investigated.
• Red light enhanced peroxidase activity, protease activity, protein content and chlorophyll.
• Green light enhanced total phenolic content, total flavonoid content and antioxidant activity.
• Correlation among callus frequency, radical scavenging activity and antioxidative enzyme was observed.

Through its impact on morphogenesis, light is the key environmental factor that alters plant architectural development; however, the understanding that how light controls plant growth and developmental processes is still poor and needs further research. In this study, we monitored the effect of various monochromatic lights and plant growth regulators (PGRs) combinations on morphogenic and biochemical variation in wild grown-leaf derived callus cultures of Artemisia absinthium L. Combination of α-naphthalene acetic acid (NAA 1.0 mg/l) and Thidiazuron (TDZ 2.0 mg/l) resulted in optimum callogenic frequency (90%) when kept under fluorescent light for 4 weeks (16/8 h). In contrast to the control (white spectrum), red spectrum enhanced peroxidase activity, protease activity, total protein content and chlorophyll a/b ratio. Green spectrum was found to be more supportive for total phenolics, total flavonoids and antioxidant activity. Yellow light enhanced MDA content while white and green light improved total chlorophyll content and carotenoid content. A positive correlation among callogenic response, antioxidant activities and set of antioxidative enzyme activities was also observed in the current report. This study will help in understanding the influence of light on production of commercially important secondary metabolites and their optimization in the in vitro cultures of A. absinthium L.