Threshold of Low Light for Growth Performance in Two Korean Endemic Hosta Species, H. minor and H. yingeri

Hosta plants are renowned for their ornamental foliage, particularly in environments with limited sunlight. The present study aimed to ascertain the critical threshold of low light for growth persistence in two Korean endemic hostas, H. minor and H. yingeri, with a view to assessing their suitability for diverse horticultural settings. Plants were exposed to low-light conditions for 12 weeks at light intensity levels of 10, 30, and 50 µmol·m^-2·s-1 PPFD (designated as L10, L30, and L50, respectively). Growth persistence, as measured by growth responses in both species, was not achieved at the lowest light intensity (L10) but was observed at L30 or L50. The initial leaf number and shoot biomass outcomes were reduced by an average of 37.3% and 44.3%, respectively, at L10 for both species during the experiment. However, light intensities above L30 had a positive effect on the growth of both species with ornamental value. The capacity for photo-physiological plasticity, as evidenced by photosynthetic performance under low-light conditions, was observed to be greater in H. minor than in H. yingeri. Nevertheless, both species exhibited photosystem integrity maintenance when the light exceeded L10. It can thus be concluded that the light intensity range of L10 to L30 represents the critical threshold for growth persistence in both species.