Adenophora triphylla var. japonica Hara is a highly valued medicinal plant that is used to treat or prevent bronchitis, cough, cancer, and obesity. However, there has been no study on the production of Adenophora triphylla var. japonica Hara seedlings in a closed-type plant production system (CPPS). This study was conducted to examine the growth characteristics of Adenophora triphylla var. japonica Hara seedlings as affected by different growing media. The seeds were sown on a 128-cell plug tray filled with urethane sponges (US), LC grow foam (LC), rockwool (RW), or terra-plugs (TP). The seedlings were cultured for a duration of 54 days under temperature 25 ± 1°C, a photoperiod of 12/12 h (light/dark), and light intensity of 180 µmol·m−2·s−1 photosynthetic photon flux density provided by RB LEDs (red:blue = 8:2) in a closed-type plant production system (CPPS). The germination rate of Adenophora triphylla var. japonica Hara was significantly highest in the TP. Also, seedling shoot growth indicators of plant height, leaf length, leaf width, number of leaves, fresh weight (FW), and dry weight (DW) of the shoot, and leaf area were markedly the greatest in the TP and the lowest in the US. The SPAD (soil-plant analysis development) value was higher in the TP and US than in the LC or RW. In addition, the seedling root growth characteristics of total root length, root surface area, root volume, and number of root tips were significantly greatest in the TP. Moreover, the maximum root diameter, FW and DW of roots were the greatest in the TP. In conclusion, the results suggest that TP are viable for the growth development of Adenophora triphylla var. japonica Hara seedlings.

To determine the adequate irrigation conditions in a nutrient-flow wick culture (NFW) system, the water contents of root media were analyzed with different wick lengths (2 and 3 cm), pot sizes (6-, 10-, and 15-cm diameter), and media compositions (mixtures of 5 peatmoss : 5 perlite and 7 peatmoss : 3 perlite). The growth of potted ‘New Alter’ kalanchoe (Kalanchoe blossfeldiana) in the NFW system was also compared with that of plants grown in other irrigation systems, such as nutrient-stagnant wick culture and ebb-and-flow culture. All factors, such as wick length, pot size, and medium composition, influenced the water content of the medium in the NFW system. Pots that included more peatmoss with a shorter wick could easily take up the nutrient solution. The water content of the media increased by more than 8% and 5% in 2- and 3-cm wick lengths within 15 minutes respectively. The fluctuation of water content became greater with a decrease of pot size in the NFW system. Kalanchoe plants grew well in the NFW system with four irrigations for 15 min per day each. The dry weight and leaf area of the plants were higher in the NFW system (4×) and considerably lower in the NFW system with two irrigations for 15 min per day each. Therefore, more precise irrigation is required in the NFW system than in other systems.

This study was performed to investigate the seed morphological characteristics and dormancy type of Adenophora triphylla var. japonica Hara that high valued medicinal crop and to select the disinfectants and light quality for germination rate improvement. The seed disinfection was carried out using distilled water (control), NaClO 4%, H 2 O 2 4%, and benomyl 500 mg•L -1 . The light quality treatments were set to dark condition (control I), fluorescent lamp (control II), LEDs [red, blue, green, and combined RB LEDs (red:blue = 8:2, 6:4, 4:6, 2:8)] with a photoperiod of 12/12 (light/dark) and light intensity 150 ± 10 µmol•m -2 •s -1 photosynthetic photon flux density. Although the Adenophora triphylla var. japonica Hara seed was an underdeveloped embryo (E) and seed (S) with an embryo (E):seed (S) ratio of 0.4, it is germinated within 30 days, and seed moisture saturation was reached within 6 hours after immersion. After seed disinfection, the mold incidence rate was significantly inhibited, and the final germination rate was the highest at 87% in the benomyl seed disinfection. The final germination rate was the highest at 92% in the red light, and the mean daily germination was the lowest in the R2B8. Therefore, there is almost no dormancy in the Adenophora triphylla var. japonica Hara seed, and benomyl seed disinfectant and red light were effective in the improvement of germination rate. So it is considered to the high value of use for medicinal crop Adenophora triphylla var. japonica Hara cultivation.

The effects of substrate water content on the growth and content of bioactive compounds in Crepidiastrum denticulatum were evaluated. Three-week-old seedlings were subjected to four levels of substrate water content (20%, 30%, 45% and 60%) and maintained for 5 weeks. Growth parameters at 5 weeks of transplanting were significantly higher with the 45% substrate water content treatment than with the other treatments. In addition, photosynthetic rate, stomatal conductance and transpiration rate increased significantly and the highest sap flow rate during the day was observed in 45% substrate water content. Total phenolic content and antioxidant capacity per shoot increased significantly with substrate water content, increasing from 20% to 45% and decreased again at 60%. Antioxidant capacity and total hydroxycinnamic acids (HCAs) content per unit dry weight of plants under the 60% treatment were significantly higher than those under the 45% treatment; however, their content per shoot was the highest under the 45% treatment. Thus, 45% substrate water content is a suitable condition for the growth of C. denticulatum and had positive effects on phenolic content, antioxidant capacity, and HCAs content. These results could be useful for the mass production of high-quality C. denticulatum in greenhouses or plant factories capable of controlling the water content of the root zone.

This study aims to determine the effect of different CO2 concentrations and light intensities on the growth, photosynthetic rate, and bioactive compound content of Glehnia littoralis Fr. Schmidt ex Miquel in a closed-type plant production system (CPPS). The plants were transplanted into a deep floating technique system with recycling nutrient solution (EC 1.0 dS·m-1 and pH 6.5) and cultured for 96 days under a temperature of 20 ± 1 °C, a photoperiod of 12/12 h (light/dark), and RGB LEDs (red:green:blue = 7:1:2) in a CPPS. The experimental treatments were set to 500 or 1500 µmol∙mol−1 CO2 concentrations in combination with one of the three light intensities: 100, 200, or 300 µmol∙m−2∙s−1 photosynthetic photon flux density (PPFD). The petiole length of G. littoralis was the longest in the 500 µmol∙mol−1 CO2 concentration with the 100 µmol∙m−2∙s−1 PPFD. The fresh weight (FW) and dry weight (DW) of shoots and roots were the heaviest in the 300 µmol∙m−2∙s−1 PPFD regardless of the CO2 concentration. Higher CO2 concentrations and light intensities produced the greatest photosynthetic rates. However, the SPAD value was not significantly different between the treatments. Higher light intensities produced greater content per biomass of chlorogenic acid and total saponin, although the concentration per DW or FW was not significantly different between treatments. The first and second harvest yields were the greatest in the 300 µmol∙m−2∙s−1 PPFD, regardless of the CO2 concentration. These results show that the 300 µmol∙m−2∙s−1 PPFD enhanced the growth, photosynthetic rate, and bioactive compound accumulation of G. littoralis, regardless of the CO2 concentration in a CPPS.