[Effects of light intensity on growth, quality and antioxidant activities of Sedum sarmentosum]

The present study was conducted to explore the effect of light intensity on growth, bioactivity compounds accumulation and anti-oxidative activity of Sedum sarmentosum. The growth, yield, contents of total flavonoids, total phenolic, quercetin, kaempferol and isorhamnetin, and antioxidant activities were assessed in S. sarmentosum under five light intensities, namely 100% full sunlight (G1), 77% full sunlight (G2), 60% full sunlight (G3), 38% full sunlight (G4), and 16% full sunlight (G5). The results showed that light intensity significantly affected the growth and the chemical compounds accumulation. With the decrease of light intensity, the maximum branch length and the average internode distance increased. G2 treatment greatly promoted the numbers of leaf layers and branches, and G3 treatment remarkably improved the yield. The highest total flavonoids and phenolic contents were obtained in G3 treatment. Meanwhile, the highest quercetin and isorhamnetin contents were obtained in G1 treatment. The difference of kaempferol content was not significant. In addition, based on DPPH, FTC and FRAP methods, the antioxidant activities of the aqueous extracts under G1 treatment were superior to the others. The results indicated that more than 60% full sunlight was the optimum light intensity condition to achieve high yield and quality of S. sarmentosum.