2015 Volume 59 Issue 4 Pages 179-189
The variation of oxypinnatanine (OPT) concentration in daylily (Hemerocallis spp.) influenced by ploidy levels, growth stages, waterlogged soil, relative light intensity, and temperature was examined. Experiments were performed using pots and a net-house with a completely random design. The quantitative estimation of OPT by high-performance liquid chromatography revealed that the ploidy level did not affect the daylily’s OPT accumulation. The OPT production by daylily plants varied significantly with growth stages. The OPT accumulated during the vegetative and flowering periods was higher than that during the post-flowering period. Waterlogged soil did not influence the production of OPT. The light intensity and the temperature markedly affected the OPT concentration in H. fulva var. sempervirens. The plants grown under 100% and 40% relative light intensity (RLI) produced significantly more OPT than those grown under 75% and 60% RLI. The OPT concentration in plants exposed to 40°C was the highest, followed by that in plants exposed to 15°C. The lowest OPT was observed in plants treated at 10°C. Plants exposed to the temperature range of 20°–35°C synthesized OPT at 1.72–1.89 mg g-1, which is lower than those of the plants treated at 15° and 40°C. These results suggest that to accumulate high concentrations of OPT, daylily could be grown in both waterlogged and well-watered soils in non-shade or severe shade conditions, and harvested during the vegetative and flowering stages. Before harvesting at 10 days, plants should be exposed to 15° or 40°C.
