Growth Responses of Korean Endemic Hosta minor under Sub-Optimal Artificial Lighting

To check the availability of indoor plants, we investigated the growth and photo-physiological responses in Korean endemic Hosta minor for three months of artificial low light conditions (10, 30, and 50 μmol·m^-2·s-1, abbreviated as L10, L30, and L50). In the L10 treatment, the growth indicators leaf number and size, shoot biomass, and tillering capacity declined by 20–50% decline from the initial values, and those were maintained or slightly increased in the L30 treatment and significantly increased to 200–300% in the L50 treatment. The light use efficiency values supported this result, which were –0.12, 0.04, and 0.16 in L10, L30, and L50, respectively. Growth adaptation to the indoor artificial lighting took four to six weeks. Net photosynthesis also decreased from the initial value after four weeks but increased in the ninth week, showing significant differences among the different light intensity levels. The light compensation point was 17 ± 6.16 μmol·m^-2·s-1, and the light saturation point ranged from 200 to 350 μmol·m^-2·s-1. Regardless of the light intensity, the F_v/F_m values were 0.79 to 0.83, indicating a normal level, and the OJIP curve also showed no significant difference. These results indicate that the low light intensity of 10 μmol·m^-2·s-1 did not damage photosystem II but gradually negatively affected the growth of Hosta minor. We concluded that the minimum light intensity is 10 to 30 μmol·m^-2·s-1 in Hosta minor and requires four weeks of low light adaptation.