Effects of Shading Levels on the Growth, Flowering, Photosynthetic Characteristics, and Spectral Reflectance of Coreanomecon hylomeconoides Nakai

Abstract

This study investigated the effects of different shading levels (0, 45, 70, and 90% shade) on the growth, flowering, photosynthetic characteristics, and spectral reflectance to determine the optimal light environment in which to cultivate Coreanomecon hylomeconoides.Plant height, leaf length, and leaf width increased when increasing the shading intensity, whereas the number of leaves, shoot fresh weight, and shoot dry weight were greatest under the 70% shade treatment.Plants grown under the 0% shade treatment exhibited poor growth, leaf chlorosis, and significantly lower chlorophyll content levels than shaded plants.Flower and flower stalk numbers were significantly higher under the 45% and 70% shade treatments than under the 90% shade treatment.The maximum net photosynthetic rate (Amax) and light saturation point (LSP) were significantly lower in the non-shaded treatment compared to all of the shaded treatments.Under the 0% shade treatment, chlorophyll fluorescence parameters associated with photosystem II efficiency, in this case Fv/Fo, Fv/Fm, ETo/TRo, ETo/ABS, ETo/RC, and PIABS, decreased, indicating excessive irradiance that caused photoinhibition.A spectral reflectance analysis also showed increased MCARI and NPCI values and decreased SRPI and PRI values under the 0% shade treatment, suggesting enhanced physiological stress and a pigment imbalance.Therefore, 45% and 70% shade treatments are recommended as the optimal light environment to cultivate and produce ornamental C. hylomeconoides, with a 70% shade treatment providing the most favorable overall performance.