Saffron is a valuable plant and one of the most expensive spices worldwide. Nowadays, there is a tendency to produce this crop in indoor plant production systems. However, the production of saffron is restricted by the need for the reproduction of high-quality corms. In this study, we investigated the effect of different ratios of red (R) and blue (B) light spectra (including 100% B (monochromatic B), 75%, 50%, 40%, 25% B, and 0% B (monochromatic R) on the photosynthetic performance and biomass partitioning as well as morphological and biochemical characteristics of saffron. The growth of flower, root, and corm was improved by increasing the proportion of B to R light. B-grown plants were characterized by the highest photosynthetic functionality with efficient electron transport and lower energy dissipation when compared to R-grown plants. B light directed biomass toward the corms and floral organs, while R light directed it toward the leaves. In saffron, the weight of a daughter corm is of great importance since it determines the yield of the next year. As the ratio of B to R light increased, the daughter corms also became heavier, at the cost of reducing their number, though increasing the proportion of B-enhanced antioxidant capacity as well as the activity of ascorbate peroxidase and catalase while superoxide dismutase activity was enhanced in R-grown plants. In conclusion, B light increased the production of high-quality daughter corms and altered biomass partitioning towards harvestable organs (corms and flowers) in saffron plants.

The agricultural sector faces challenges due to climate change and the growing global population. Alkaline stress could adversely impact plant growth and crop production. This stressor diminishes water quality essential for crop cultivation, consequently impairing plant growth and overall productivity. Gamma-aminobutyric acid (GABA), a non-protein amino acid, may exhibit multifaceted roles in plant responses to adverse environmental conditions. Optimization of crop production in controlled environmental agriculture under artificial light attracted much attention. In the present study, we investigated the effects of different light spectra and GABA concentrations on Lollo Rosso lettuce plants under alkaline stress. Seedlings were placed under different light spectra [red (R), blue (B), white (W), 3R:1B, and 2R:1B:1far red (FR)] and treated with GABA (0 and 50 µmol). Alkaline conditions were instituted by applying NaHCO₃ at a concentration of 40 mM. The experiment incorporated a control treatment without NaHCO₃. In general, R light exposure caused the highest growth performance of lettuce plants. GABA augmented biomass production in control and alkaline-treated plants across all light spectra. Additionally, it increased the concentrations of photosynthetic and protective pigments under alkaline conditions. GABA also improved the photosynthetic performance under all light spectra. Non-photochemical quenching and pigmentation were enhanced by exposure to B light, especially in plants treated with GABA. Alkaline stress induced an increase in soluble carbohydrate content in the lettuce leaves. These findings highlight the support of GABA application in facilitating coping plants to alkaline stress.

Saffron ( Crocus sativus L.), prized for its culinary, cosmetic, and medicinal uses, faces challenges such as climate change and resource-intensive farming. Controlled environment agriculture (CEA) offers a solution by optimizing growing conditions, particularly for producing large daughter corms essential for yield. This study investigated the impact of various light spectra—blue (B), red (R), and far-red (FR) combinations (1B:1R, 1B:1FR, 1B:2R:1FR, and 1R:1FR)—on saffron growth, photosynthesis, and carbohydrate biosynthesis genes (i.e., CsSUS1 , CsPhol , SBE ). Results showed that R and FR light enhanced leaf growth and photosynthesis but reduced underground biomass, while a balanced R and FR light increased daughter corm production. Molecular analysis indicated that FR light elevated soluble carbohydrates but decreased carbohydrate storage. The highest CsSUS1 expression occurred under 1R:1FR light, whereas CsPhol and SBE , associated with starch biosynthesis, were upregulated under 1B:1R light. A strong correlation was observed between CsSUS1 expression and soluble carbohydrate content. In summary, FR light promotes vegetative growth while reducing starch accumulation, resulting in smaller daughter corms. In contrast, R and B light enhance starch-related gene expression, increasing daughter corm size. These findings underscore the potential of light spectrum manipulation in CEA to optimize saffron corm production with minimal resource input.