Coriander is an important aromatic plant, and contains abundant secondary metabolites that are considered to be beneficial for health. The demand for high-quality and fresh coriander in large cities has been growing rapidly. Plant factories are advanced indoor cultivation systems that can produce high-quality plants inside cities with a high productivity. This study aimed to maximize plant growth and the secondary metabolites production of coriander, by regulating photosynthetic photon flux density (PPFD) and root-zone temperature (RZT). Three PPFDs (100, 200, and 300 µmol m⁻² s⁻¹) and three RZTs (20, 25, and 30 °C) were applied on coriander plants grown hydroponically in a plant factory. The plant biomass and water content of leaf and stem were highest under RZT of 25 °C with a PPFD of 300 µmol m⁻² s⁻¹. However, chlorogenic acid, rutin, trans-2-decenal, total phenolic concentrations and the antioxidant capacity of the coriander plant were greatest under the combination of PPFD (300 µmol m⁻² s⁻¹) and RZT (30 °C). Chlorogenic acid in leaves responded more sensitively to PPFD and RZT than rutin. Controlling PPFD and RZT is effective in optimizing the yield and quality of coriander plants. The findings are expected to be applied to commercial plant production in plant factories.

The demand for high-nutrient and fresh vegetables, including coriander, has been growing rapidly. A plant factory with artificial lighting enables the application or suppression of stress conditions to plants for producing high-quality vegetables. This study aimed to determine a suitable root-zone temperature (RZT) treatment for enhancing the biomass and secondary metabolite content of hydroponic coriander plants. The combination of a mid-RZT (25 °C) pre-treatment with low (15 °C or 20 °C) or high (30 °C or 35 °C) RZT for a short period (3 or 6 days) was applied to the plants before harvesting. The fresh weights of the coriander plants were reduced under RZT stress. By contrast, the content of secondary metabolites, including ascorbic acid, carotenoids, phenolic compounds, chlorogenic acid, and the antioxidant capacity of the plants were enhanced by the combination of the lowest or highest RZT (15 °C or 35 °C) and the longer stress period (6 days). Growing coriander under an RZT of 30 °C for 6 days can produce large amounts of bioactive compounds and water, whereas growing coriander at an RZT of 15 °C for 6 days can produce high dry biomass and secondary metabolite content.

This perspective paper examines the research and development challenges faced by plant factories with artificial lighting (plant factories hereafter). The global and local challenges facing our planet can be divided into the following four categories: (1) food and agriculture; (2) environment and ecosystems; (3) depletion, uneven distribution, and the overuse of nonrenewable resources; and (4) society, economy, and quality of life. All of the aspects of this four-way deadlock problem must be resolved simultaneously, since solving only one of them could exacerbate one or more of the remaining three. In this paper, the role of plant factories in solving the four-way deadlock problem is discussed from the following perspectives: (1) civilization and culture, (2) participatory science, and (3) the integration of biotechnology and the latest nonbiological technology, such as artificial intelligence (AI). The relationship and interactions between the environment and plant ecosystems are easily observed in the plant factories’ cultivation room. Thus, it is easy to analyze their relationship and interactions. The findings from such observations can also be applied to increase the yield in plant factories, with minimum resource inputs. Moreover, if the electricity generated by renewable energy sources is used, it will become an energy-autonomous plant factory. This means that the plant factory can be operated with the minimum contribution of greenhouse gas emissions to global warming and land area use.

The consumption of edible flowers is gaining global popularity due to their culinary appeal, vibrant colors, and health-promoting compounds. Traditional production methods—including wild collection, open-field cultivation, and greenhouse systems—offer limited control over environmental factors, often resulting in inconsistent yield, quality, and safety. To address these limitations, plant factories with artificial lighting (PFALs) have emerged as a promising technology for producing high-quality edible flowers year-round in controlled environments. This review explores the evolution of edible flower cultivation, from conventional methods to PFALs, and highlights key environmental factors—light, temperature, and nutrient management—that influence growth, flowering, and phytochemical profiles. Special attention is given to how light intensity, spectrum, and photoperiod affect morphogenesis and metabolite accumulation, and how nutrient solution composition, particularly nitrogen form and EC levels, modulates flowering and plant health. While recent studies have demonstrated the potential of PFALs in cultivating species such as calendula, nasturtium, and marigold, research remains limited for many commercially relevant species. The review identifies current challenges, such as high operational costs and knowledge gaps in species-specific protocols, and outlines future research directions aimed at improving efficiency, optimizing quality, and expanding market viability. PFALs offer a transformative opportunity for the edible flower industry by integrating precision agriculture with consumer demand for safe, functional, and visually appealing food products.

This study evaluated the growth, physiological, chlorophyll fluorescence (JIP-test), and postharvest responses of a shoot-dominant (‘C-P’) and a root-dominant (‘J-L’) garlic material to graded salinity (0, 50, and 200 mM NaCl) in a hydroponic system, with or without seed-clove priming using LEAFENERGY^®, a commercial biostimulant mainly composed of naturally derived rare fatty acids. Results showed 50 mM NaCl significantly inhibited shoot growth, while 200 mM nearly arrested growth and induced clove decay. Under moderate salinity, biostimulant priming exhibited cultivar-dependent mitigation. In ‘C-P’, biostimulant priming increased clove soluble sugar content by 1.140 g 100 g⁻¹ FW under 50 mM NaCl and increased dry-weight-based clove water content after cold storage. In ‘J-L’, biostimulant priming increased SPAD values under 50 mM NaCl and reduced the salt-induced increase in clove yellowness index to a level not significantly different from the non-saline control. In conclusion, garlic’s response to salinity is fundamentally dictated by intrinsic resource allocation strategies. Rather than merely promoting growth, biostimulant priming optimizes photosynthetic energy fluxes and reshapes metabolism. This tailored approach effectively preserves the visual marketability of susceptible cultivars while enhancing osmoprotectant accumulation and hydration in vigorous morphotypes, providing a sustainable strategy to safeguard industrial raw materials in salinized controlled cultivation systems.

Soil salinization severely limits the stable production of garlic (Allium sativum L.) and compromises the postharvest storability of seed cloves as industrial planting materials. This study evaluated the morpho-physiological, photosynthetic (JIP-test), and postharvest responses of a shoot-dominant ('C-P') and a root-dominant ('J-L') garlic cultivar to graded salinity (0, 50, 200 mM NaCl) in a hydroponic system, with or without seed-clove priming using a novel commercial biostimulant. Results showed 50 mM NaCl significantly inhibited shoot growth, while 200 mM nearly arrested growth and induced clove decay. Under moderate salinity, LE priming exhibited cultivar-dependent mitigation. In 'C-P', it promoted root branching, enhanced soluble sugar accumulation, and improved postharvest tissue hydration. In 'J-L', biostimulant elevated leaf SPAD values, fully reversed stress-induced clove yellowing, and significantly suppressed postharvest fungal decay during cold storage. In conclusion, garlic's response to salinity is fundamentally dictated by intrinsic resource allocation strategies. Rather than merely promoting growth, biostimulant priming optimizes photosynthetic energy fluxes and reshapes metabolism. This tailored approach effectively preserves the visual marketability of susceptible cultivars while enhancing Osmo protectant accumulation and hydration in vigorous morphotypes, providing a sustainable strategy to safeguard industrial raw materials in salinized controlled cultivation systems.