The impacts of lighting parameters on the growth and antioxidant properties of Kalanchoe pinnata in controlled environment

The aim of this study was to evaluate the effects of light emitting diodes (LED) lighting parameters on Kalanchoe pinnata growth and antioxidant properties seeking for high quality medicinal plant material cultivation in controlled environment agricultural systems. Plants were grown for 40 days in phytotron chamber (21/17 degrees C day/night temperature, RH 65%) in peat substrate under differential lighting conditions. Seeking to evaluate the impacts of lighting photoperiod and photosynthetic photon flux density (PPFD), Kalanchoe plants were cultivated under LED lighting, 18 and 24 h photoperiod and 150, 250 mu mol m(-2) s(-1) PPFD. To evaluate the effects of lighting spectrum, plants were cultivated under combinations of red (660 nm), blue (445 nm) and supplemental green (520 nm) of far red (740 nm) within 18 h photoperiod and total PPFD of 250 mu mol m(-2) s(-1). The results obtained show, that higher light intensity tend to enhance the antioxidant properties of Kalanchoe plants as well as the contents of bersaldegenin-1,3,5-orthoAc, the main identified bufadienolide in Kalanchoe tissues. Highest plant biomass was accumulated in plants, illuminated with 18 h photoperiod and 250 mu mol m(-2) s(-1) PPFD, when the highest DPPH, ABTS free radical scavenging activities, FRAP antioxidant power and bufadienolide concentrations were determined in those, illuminated with 250 mu mol m(-2) s(-1) PPFD for 24 h. Analysing the impact of lighting spectrum, supplemental green and far red light did not have significant effect on antioxidant value of Kalanchoe plants, compared to red + blue light spectrum.

Automated summary

The study aimed to evaluate the effects of LED lighting parameters on Kalanchoe pinnata growth and antioxidant properties. Higher light intensity tended to enhance the antioxidant properties and bufadienolide contents. The combination of red and blue light spectrum had a more significant effect on antioxidant value compared to supplemental green and far red light.