Impact of light quality on flavonoid production and growth of hyptis marrubioides seedlings cultivated in vitro

Abstract

Hyptis marrubioides Epling, Lamiaceae, a species from Brazilian Cerrado, has been used against gastroin-testinal infections, skin infections, pain, and cramps. Herein, H. marrubioides seedlings were culturedin vitro under different wavelengths (white, blue, green, red, and yellow) with 50 μmol m−2s−1 irra-diance and a 16-h photoperiod. After 20 and 30 days of cultivation, shoot length, leaf number, freshmass, and dry mass were evaluated. The flavonoid rutin content was determined by the HPLC-DADmethod. The shoots were longer in plants cultivated under yellow (16.603 ± 0.790 cm, 1.8-fold), red(15.465 ± 0.461 cm, 1.7-fold), and green (14.677 ± 0.737 cm, 1.6-fold) lights than in control plants exposedto white light (9.203 ± 0.388 cm). The number of leaves increased in plants exposed to red (23.425 ± 1.138,1.1-fold) and green (22.725 ± 1.814, 1.1-fold) lights, compared to control plants (20.133 ± 0.827). Fresh(0.665 ± 0.048 g, 1.2-fold) and dry (0.066 ± 0.005 g, 1.3-fold) mass of seedlings were the highest inseedlings grown under red light, compared to seedlings grown under white light (0.553 ± 0.048 and0.028 ± 0.004, respectively). However, rutin production was higher under white (0.308 mg g−1 of dryweight) and blue lights (0.298 mg g−1 of dry weight). Thus, red light induces plant growth and increasesleaf number and dry weight in in vitro-cultivated H. marrubioides, whereas blue and white lights promotethe greatest rutin accumulation.