Influence of Three Soil Types in Okinawa, Japan and N, P, K Fertilizations on Growth, Yield, and Oxypinnatanine Concentration of Hemerocallis fulva L. var. sempervirens

摘要

Hemerocallis fulva var. sempervirens is a perennial medicinal plant, containing oxypinnatanine (OPT), which has well shown sedative and sleep-improving effects. We performed two pot experiments examining the growth, yield and OPT accumulation of thisplant in three soil types in Okinawa, Japan, (dark-red, gray, and red soils), and eight quantitative combinations of N, P, K at 0.0-0.6 g pot"1 in dark-red soil. It was found that dark-red soil was the best for plant growth and yield, next by gray soil.The plants in red soil accumulated the significantly more OPT (2.19 g mg g"1 fresh leaf) than those in gray soil (1.85 mg g"1), and similar to plants in dark-red soil (2.16 mg g~(-1)), but their growth and yield were lower than those in the other soils.Consequently, dark-red soil is advised to use for cultivation of this plant. In dark-red soil, the growth and leaf yield of this plant were proportional to the applied N, P, K quantity, especially N amount, whereas the flower yield and OPT concentrationwere not. The N amount at 0.6 g pot~(-1) promoted the leaf yield better, at 0.3-0.4 g pot~(-1) was better for flower yield, and the combinations of 0.3-0.4 g N with 0.3 g P, and K per pot were ideal for OPT accumulation. The results suggested the N, P, Kcombination at 0.4 g pot"1 is the best for cultivation H. sempervirens in dark-red soil to obtain OPT.