The efficient propagation of virus-free sweetpotato seedlings is a critical challenge for maintaining stable production. This study evaluated two propagation methods—single-node cutting (SNC) and tuberous root propagation (TRP)—in two cultivars (Beniharuka and Himeayaka). Compared to TRP, SNC significantly improved seedling propagation efficiency, producing over 12 times more transplants in 70 days. SNC seedlings also showed enhanced photosynthetic performance before transplanting. After transplanting to the field, SNC seedlings achieved significantly higher storage root yield (30%-50% increase) without compromising root quality, including starch and sugar content. These findings demonstrate that the SNC method is a highly efficient and practical approach for sweetpotato seedling production. The adoption of this method could contribute significantly to improving the sustainability and productivity of sweetpotato cultivation globally.

Light quality is a critical determinant in controlling the quality of strawberry transplants in plant factories with artificial lighting (PFALs). However, the impact of full-spectrum LEDs with varying red-to-blue ratios on the growth and biomass accumulation of strawberry transplants remains inadequately explored. Moreover, the influence of the strawberry transplants obtained on runner plant propagation in greenhouses post-transplanting is unclear. For this reason, this study utilized full-spectrum LEDs (white LEDs and white and red LEDs) with red-to-blue ratios of 0.9 (W0.9), 1.5 (WR1.5), 2.0 (W2.0), and 2.9 (WR2.9) for producing strawberry transplants in the PFAL over a period of 39 d. Subsequently, ten randomly selected transplants from each above treatment were planted as mother plants in a Chinese solar greenhouse for runner plant propagation, continuing for 98 d. These treatments were named as M-W0.9, M-WR1.5, M-W2.0, and M-WR2.9, respectively. Results indicated that the total leaf area of transplants in W2.0 was 1.2 times greater than those in W0.9 and WR2.9, exceeding 300 cm². Conversely, the net photosynthetic rate and F_v/F_m of strawberry transplant leaves were significantly higher in W0.9 compared with other treatments, declining with increasing red-to-blue ratio. In terms of biomass and morphological attributes, transplants in W2.0 exhibited higher fresh mass (17.2 g), leaf count (7 per plant), crown diameter (9.9 mm), and crown dry mass (0.27 g) than other treatments. Therefore, the strawberry transplant quality in W2.0 was significantly better than that of the other treatments. Moreover, shoot dry mass of strawberry mother plants in M-W2.0 was 1.4 and 1.3 times greater than those in M-W0.9 and M-WR2.9, respectively. The number of total runner plants and three-leafed runner plants produced in M-W2.0 were 1.9 times higher than those in M-W0.9, averaging 21 and 18 per plant, respectively. And mother plants in M-W2.0 produced 7 runners per plant, resulting in increased runner plant numbers. In conclusion, full-spectrum LEDs with a red-to-blue ratio of 2.0 enhanced the quality of strawberry transplants and significantly promoted runner plant propagation in greenhouses post-transplanting, and can be recommended as effective light sources for strawberry transplant production in PFALs.

Unstable pH of nutrient solution in hydroponic systems is a major obstacle to production. To simplify the management of nutrient solution pH and attenuate negative effects of pH on plant growth, this study investigated the effect of different buffer salt additions on nutrient solution pH, ion uptake, growth and photosynthesis of Yamazaki lettuce, with the equivalent concentrations of macro-element unchanged. The results indicated that the pH of nutrient solution was buffered to varying degrees by the 2 mol/L $\mathrm{H}\mathrm{C}{\mathrm{O}}_3^{-}$, 1 mol/L $\mathrm{H}\mathrm{C}{\mathrm{O}}_3^{-}$, and 0.33 mol/L $\mathrm{H}\mathrm{P}{\mathrm{O}}_4^{2-}$ treatments. The 0.33 mol/L $\mathrm{H}\mathrm{P}{\mathrm{O}}_4^{2-}$ treatment fluctuated most with a pH of 1.74 units, while the addition of $\mathrm{H}\mathrm{C}{\mathrm{O}}_3^{-}$ buffered nutrient solution pH was better, with higher pH values (7.2-7.7). The CK-pH control solution, 1 mol/L $\mathrm{H}\mathrm{C}{\mathrm{O}}_3^{-}$ and 0.33 mol/L $\mathrm{H}\mathrm{P}{\mathrm{O}}_4^{2-}$ treatments all promoted the uptake of ion and then the growth of lettuce was better in comparison with the CK-pH no adjustment treatment, while the 2 mol/L $\mathrm{H}\mathrm{C}{\mathrm{O}}_3^{-}$ treatment inhibited K uptake and reduced the availability of Fe, the shoot and root fresh weight of lettuce decreased by 21.3% and 10.1%, respectively. In addition, although the chlorophyll content and net photosynthetic rate under 1 mol/L $\mathrm{H}\mathrm{C}{\mathrm{O}}_3^{-}$ and 0.33 mol/L $\mathrm{H}\mathrm{P}{\mathrm{O}}_4^{2-}$ treatments were significantly lower than the CK-pH control solution treatment, there were no significant differences in leaf length and leaf number of lettuce among them, and shoot fresh weight per plant was 83.09, 82.95, and 78.92 g, respectively. In conclusion, adding 1 mol/L $\mathrm{H}\mathrm{C}{\mathrm{O}}_3^{-}$ to the nutrient solution in a single dosage not only buffered the pH of nutrient solution better but also promoted ion uptake, it had no negative effects on the growth, photosynthesis and ion uptake of hydroponic lettuce in comparison with the CK-pH control solution treatment. Therefore, 1 mol/L $\mathrm{H}\mathrm{C}{\mathrm{O}}_3^{-}$ can be used as a buffer during the growth of hydroponic lettuce and reduce frequent addition of acids or alkalis, and then simplify the management of nutrient solution for hydroponic lettuce production.

Atractylodes Chinensis (DC) Koidz is a perennial herb often used as a prescription medicine for influenza, to invigorate the spleen and remove dampness. The quality of the herb is determined by the quality of the seedlings. The traditional A. chinensis seedling production technique has nonuniform seedlings and low mechanisation. The plug seedling technique was used to produce A. Chinensis seedlings. This study was conducted to determine the growth characteristics of A. Chinensis seedlings according to the cell size of plug trays and number of days after sowing. Plant height, stem diameter, rhizome diameter, number of leaves, leaf area, and shoot dry and fresh weight of A. Chinensis seedlings were significantly higher in the P32-D treatment than in the P72, P50, and P32 treatments, but not significantly different from the P28-D treatment 60 d after sowing. The P28-D treatment resulted in a considerable drop in rhizome fresh weight and healthy seedling index, both of which are key indicators for assessing seedling quality. Although the differences in Pn among treatments were not significantly different, Tr was considerably greater in A. Chinensis seedlings treated with P32-D and P28-D than in the other three treatments. The P32-D and P28-D treatments had considerably greater potential maximum photochemical efficiency of PSII, quantum yield of photosystem II, photochemical quenching and electron transport rate than the other three treatments. Root vitality of A. Chinensis seedlings was significantly stronger in the P32-D treatment than in the other four treatments, and it was 1.9 times higher than in the P28-D treatment. The soluble protein, soluble sugar, and starch contents of A. Chinensis seedlings were highest in the P32-D treatment, but the differences among treatments were not significant. LUE, EUE, PY and EY were significantly higher in the P32-D treatment than in the other four treatments, being 1.3, 1.3, 1.4 and 1.4 times higher than in P28-D, respectively. On the other hand, as for the change in the growth of A. Chinensis seedlings according to the number of days after sowing, the growth of shoots and rhizome was most vigorous at the 60 d after sowing, while the fresh weight of the rhizome, which can be considered as an indicator of root growth, increased steadily during the experiment but slowed down after 60 d. As a result, 32-cell deepened plug trays and a seedling nursery for a period of 60-75 d are recommended for commercial cultivation of A. Chinensis seedlings. This will provide technical support for production in A. Chinensis seedling.

Supplemental lighting is critical to the growth of greenhouse crops under the environmental conditions of low temperatures combined with weak radiation during the winter and spring seasons. To achieve the essential daily light integral (DLI) for greenhouse crop growth, a supplemental light strategy was proposed based on hourly light integral (HLI). The target HLI was calculated by dividing the target DLI by the duration of light exposure, while the actual HLI was obtained by accumulating the Photosynthetic Photon Flux Density (PPFD) based on real-time monitoring. Subsequently, the supplemental lighting duration for the next hour was determined by the difference between the target HLI and the actual HLI from all previous periods. Furthermore, the supplementary lighting strategy incorporated maximum values for both PPFD and temperature, and the supplemental light was withheld whenever the actual PPFD or temperature exceeded these values. An experiment was conducted on strawberries in a commercial greenhouse, targeting a DLI of 12.6 mol/(m²∙d), with no supplemental lighting as the control. The results indicated that LED supplemental lighting based on HLI increased the DLI to approximately 10 mol/(m²∙d) and raised the strawberry canopy temperature by 1°C-2°C. Compared to the control treatment, the LED supplemental lighting based on HLI significantly improved the net photosynthetic rate, stem thickness, number of leaves, leaf length, and leaf width of the strawberry plants. Additionally, the fruit yield per plant, soluble solids content, and sugar-acid ratio in the supplemental lighting treatment increased by 32%, 21%, and 33%, respectively. Thus, LED supplemental lighting based on HLI is an effective strategy for improving the yield and quality of greenhouse crop production.