Shaofang Wu

The light environment is a key factor in regulating crop growth and quality in plant factories, where both light intensity and photoperiod strongly influence photosynthetic productivity and energy consumption. This study aimed to elucidate the interactive effects of light intensity and photoperiod on the growth, photosynthetic performance, and energy-use efficiency of Pakchoi in a controlled environment, thereby optimizing lighting strategies. Here, three levels of light intensity (PPFD: 100, 175, and 250 μmol·m⁻²·s⁻¹) and four photoperiods (8, 12, 16, and 20 h·d⁻¹) were combined, resulting in twelve treatments. Plant growth parameters, chlorophyll content, gas exchange indices, CO₂ response curves, and chlorophyll fluorescence characteristics were measured, along with analyses of light-use efficiency (LUE) and electrical energy-use efficiency (EUE). The highest biomass accumulation was observed under a 20 h·d⁻¹–250 μmol·m⁻²·s⁻¹ treatment. In contrast, the optimal LUE (9.69%) and EUE (4.98%) were observed under a 20 h·d⁻¹–175 μmol·m⁻²·s⁻¹ treatment. The best photosynthetic performance (A_max 32.61 μmol·m⁻²·s⁻¹) occurred under a 16 h·d⁻¹–250 μmol·m⁻²·s⁻¹ treatment. This study integrates growth, photosynthetic physiology, and energy-use efficiency, revealing a trade-off between biomass production and energy utilization in Pakchoi cultivation. It clarifies that “moderate light intensity + long photoperiod” is the optimal strategy to balance yield and energy consumption in plant factories.

Facing the significant challenges posed by global population growth and urbanization, plant factories, as an efficient closed cultivation system capable of precise environmental control, have become a key direction in the development of modern agriculture. However, high energy consumption, particularly lighting (which accounts for over 50%), remains a major bottleneck limiting their large-scale application. This study systematically explored the effects of dynamic light regulation strategies on lettuce (Lactuca sativa L.) growth, physiological and biochemical indicators (such as chlorophyll, photosynthetic, and fluorescence parameters), nutritional quality, energy utilization efficiency, and post-harvest shelf life. Four different light treatments were designed: a stepwise increasing photosynthetic photon flux density (PPFD) from 160 to 340 μmol·m⁻²·s⁻¹ (T1), a constant light intensity of 250 μmol·m⁻²·s⁻¹ (T2), a three-stage strategy with high light intensity in the middle phase (T3), and a three-stage strategy with sequentially increasing light (T4). The results showed that the T4 treatment exhibited the best overall performance. Compared with the T2 treatment, the T4 treatment increased biomass by 23.4%, significantly improved the net photosynthetic rate by 50.32% at the final measurement, and increased ascorbic acid (AsA) and protein content by 33.36% and 33.19%, respectively. Additionally, this treatment showed the highest energy use efficiency. On the 30th day of treatment, the light energy use efficiency (LUE) and electrical energy use efficiency (EUE) of the T4 treatment were significantly increased, by 23.41% and 23.9%, respectively, compared with the T2 treatment. In summary, dynamic light regulation can synergistically improve crop yield, chlorophyll content, photosynthetic efficiency, nutritional quality, and energy utilization efficiency, providing a theoretical basis and solution for precise light regulation and energy consumption reduction in plant factories.

Twenty-nine samples of two cucumber types (Cucumis sativus L.) were evaluated to determine the amino acid, tannin, soluble protein, soluble sugar, Vc, nitrate nitrogen contents and volatile organic compounds (VOCs). Cucumber variety differences in amino acid, tannin, soluble proteins, et al., were significant (p < 0.05). The VOCs were derived by headspace solid-phase microextraction (HS-SPME) coupled with gas chromatography–mass spectrometry (GC-MS). A total of 67 VOCs were identified, including 24 aldehydes, 13 alcohols, 12 ketones, 12 alkenes and 6 other compounds. (E, Z)-2,6-Nonadienal, (E)-2-Nonenal and (E)-6-Nonenal were the three most abundant volatiles. A total of 21 VOCs were present in all 29 cultivars. An average of 45 kinds of VOCs were identified in each cultivar. Principal component analysis (PCA) clustered the 29 cucumber cultivars into five groups. Partial least-squares-discriminant analysis (PLS-DA) indicated that the European type was separated from the South China type across PLS1. Furthermore, 25 key differential volatiles for distinguishing 29 cultivars and 23 key differential volatiles for differentiating between South China and European types were identified, respectively. These results provide information for the development of new cultivars with high nutritional quality and intense flavor.

The auxin efflux transporter PIN protein plays a crucial role in the asymmetric distribution of auxin on the plasma membrane, influencing the growth and development of plant organs. In this study, we identified nine members of the PIN gene family in the cucumber genome, which could be classified into five phylogenetic groups. These genes have diverse structures but conserved transmembrane domains. Analysis of cis-acting elements in the promoters revealed that CsPINs contain 48 types of cis-acting elements, predominantly light-responsive elements and plant hormone response elements. In addition, PIN proteins may interact with a variety of auxin-related proteins (including auxin response factor, auxin binding protein, mitogen-activated protein kinase PINOID, etc.) to jointly regulate the auxin synthesis and metabolic pathways. We analyzed the expression profiles of PIN genes in 23 tissues of cucumber using the CuGenDB database, and further investigated the expression levels of PIN genes in leaves and roots in response to different abiotic stresses and hormone treatments by qRT-PCR. This study provides a theoretical basis for clarifying the regulatory mechanism of the cucumber PIN gene family during environmental stress processes.

In this study, red–blue light (7R3B) was used as the control (CK), while far-red (FR) and ultraviolet-A (UVA) light were supplemented to evaluate their effects on basil growth. The results showed that the FR treatment promoted plant height, stem diameter, and biomass, but reduced chlorophyll and carotenoid content, while the UVA treatment increased stem diameter and chlorophyll b content. Meanwhile, transcriptomic and metabolomic analyses were employed to examine changes in gene expression and metabolite accumulation in basil. The FR treatment reduced the levels of differentially accumulated metabolites (DAMs) in the carotenoid biosynthesis pathway, potentially contributing to the observed decrease in chlorophyll. The FR treatment upregulated the levels of five DAMs (gibberellin, cytokinin, brassinosteroid, jasmonic acid, and salicylic acid) and altered the differentially expressed genes (DEGs) such as gibberellin receptor (GID1) and jasmonate ZIM domain-containing protein (JAZ) in the plant hormone signal transduction pathway, thereby promoting plant growth and shade avoidance responses. The UVA treatment upregulated the 9-cis-epoxycarotenoid dioxygenase (NCED) expression in the carotenoid biosynthesis pathway, possibly indirectly promoting flavonoid synthesis. In the flavonoid biosynthesis pathway, the UVA treatment also promoted flavonoid accumulation by upregulating DEGs including flavonol synthase (FLS), anthocyanidin synthase (ANS), 5-O-(4-coumaroyl)-D-quinate 3′-monooxygenase (CYP98A), and flavanone 7-O-glucoside 2″-O-beta-L-rhamnosyltransferase (C12RT1), as well as increasing the levels of DAMs such as kaempferol, luteolin, apigenin, and leucopelargonidin. The accumulation of flavonoids improved antioxidant capacity and nutritional value in basil. Through a Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment analysis, this study provided valuable insights into the molecular and metabolic mechanisms of the FR and UVA regulation of basil growth, providing guidance for optimizing supplementary lighting strategies in plant factories.

To investigate the effects of different light qualities on the growth, photosynthesis, transcriptome, and metabolome of mint, three treatments were designed: (1) 7R3B (70% red light and 30% blue light, CK); (2) 7R3B+ far-red light (FR); (3) 7R3B+ ultraviolet light A (UVA). The results showed that supplemental FR significantly promoted the growth and photosynthesis of mint, as evidenced by the increase in plant height, plant width, biomass, effective quantum yield of PSII photochemistry (F_v’/F_m’), maximal quantum yield of PSII (F_v/F_m), and performance index (PI). UVA and CK exhibited minimal differences. Transcriptomic and metabolomic analysis indicated that a total of 788 differentially expressed genes (DEGs) and 2291 differential accumulated metabolites (DAMs) were identified under FR treatment, mainly related to plant hormone signal transduction, phenylpropanoid biosynthesis, and flavonoid biosynthesis. FR also promoted the accumulation of phenylalanine, sinapyl alcohol, methylchavicol, and anethole in the phenylpropanoid biosynthesis pathway, and increased the levels of luteolin and leucocyanidin in the flavonoid biosynthesis pathway, which may perhaps be applied in practical production to promote the natural antibacterial and antioxidant properties of mint. An appropriate increase in FR radiation might alter transcript reprogramming and redirect metabolic flux in mint, subsequently regulating its growth and secondary metabolism. Our study uncovered the regulation of FR and UVA treatments on mint in terms of growth, physiology, transcriptome, and metabolome, providing reference for the cultivation of mint and other horticultural plants.

The duration of light exposure is a crucial environmental factor that regulates various physiological processes in plants, with optimal timing differing between species and varieties. To assess the effect of photoperiods on the growth and metabolites of a specific truss tomato cultivar, three photoperiods (12 h, 16 h, and 20 h) were tested in a plant factory. Growth parameters, including plant height, stem diameter, fresh and dry weights of shoots and roots, photosynthetic characteristics, mineral content, and metabolome profiles, were analyzed under these conditions. The results indicated that prolonged light exposure enhanced plant growth, with the highest photosynthesis and chlorophyll content observed under a 20 h photoperiod. However, no significant correlation was observed between the photoperiod and the mineral element content, particularly for macro minerals. Metabolome analysis revealed that different photoperiods influenced the accumulation of metabolites, particularly in the lipid metabolism, amino acid metabolism, and membrane transport pathways. Long periods of light would enhance photosynthesis and metabolism, improving the rapid growth of tomato seedlings. Overall, this study provides a theoretical basis for understanding the responses of truss tomato cultivars to varying photoperiods in plant factories and proposes an optimizable method for accelerating the progress of tomato seedling cultivation.