Effects of photoperiod, potassium, and growth regulators on micropropagation of Ocimum basilicum L. ‘Genovese’

Medicinal plants are important in the pharmaceutical, cosmetic, and food industry owing to the diversity of their chemical composition. Basil (Ocimum basilicum L.) is a medicinal plant that is frequently used to produce cosmetics and food. However, the effects of factors such as photoperiod, growth regulators, and nutrients on growth during micropropagation are not comprehensively understood. The objective of this study was to assess the effect of different photoperiods and growth regulators on in-vitro growth and biochemical activity of the O. Basilicum 'Genovese' cultivated using a potassium-supplemented culture medium. The experiments were carried out in a completely causalized design and were conducted using a Murashige and Skoog culture medium plus sucrose and agar. In the first experiment, seeds were inoculated at three different photoperiods in the presence or absence of growth regulators. In the second experiment, growth media containing five different concentrations of potassium iodide (KI) (0, 25, 50, 75, and 100 μM) were used. Basil seedlings grown at photoperiods of 16h and 24h produced more leaves and larger length and shoot mass, and addition of growth regulators showed no effect. However, the root systems produced the highest average values at a photoperiod of 16 h and when growth regulators were supplemented (0.23 g ±0,08). Antioxidant activity and the concentration of ascorbate peroxidase were higher under the 16 h light treatment and with addition of growth regulators. Addition of potassium to the growth medium had no beneficial effects on seedlings. Antioxidant activity was not affected by potassium concentrations, but it remained high (above 13.5%) when compared with the previous treatment. Catalase activity was the highest in seedlings grown at the highest concentrations of KI. The catalase enzyme is considered a stress indicator, so in higher concentrations of KI there is evidence that the basil plants may have had oxidative damage