Microgreens are foods with high nutritional value, which can be further enhanced with biofortification. Crop biofortification involves increasing the accumulation of target nutrients in edible plant tissues through fertilization or other factors. The purpose of the present study was to evaluate the potential for biofortification of some vegetable microgreens through iron (Fe) enrichment. The effect of nutrient solution supplemented with iron chelate (1.5, 3.0 mg/L) on the plant’s growth and mineral concentration of purple kohlrabi, radish, pea, and spinach microgreens was studied. Increasing the concentration of Fe in the medium increased the Fe content in the leaves of the species under study, except for radish. Significant interactions were observed between Fe and other microelements (Mn, Zn, and Cu) content in the shoots. With the increase in the intensity of supplementation with Fe, regardless of the species, the uptake of zinc and copper decreased. However, the species examined suggested that the response to Fe enrichment was species-specific. The application of Fe didn’t influence plant height or fresh and dry weight. The chlorophyll content index (CCI) was different among species. With increasing fertilisation intensity, a reduction in CCI only in peas resulted. A higher dose of iron in the medium increased the fluorescence yield of spinach and pea microgreens. In conclusion, the tested species, especially spinach and pea, grown in soilless systems are good targets to produce high-quality Fe biofortified microgreens.

The spectrum of light significantly influences the growth of plants cultivated in closed systems. Five lettuce cultivars with different leaf colours were grown under white light (W, 170 μmol m⁻² s⁻¹) and under white light with the addition of red (W + R) or blue light (W + B) (230 μmol m⁻² s⁻¹). The plants were grown until they reached the seedling phase (30 days). Each cultivar reacted differently to the light spectrum applied. The red-leaved cultivar exhibited the strongest plasticity in response to the spectrum. The blue light stimulated the growth of the leaf surface in all the plants. The red light negatively influenced the length of leaves in the cultivars, but it positively affected their number in red and dark-green lettuce. It also increased the relative chlorophyll content and fresh weight gain in the cultivars containing anthocyanins. When the cultivars were grown under white light, they had longer leaves and higher value of the leaf shape index. The light-green cultivars had a greater fresh weight. Both the addition of blue and red light significantly increased the relative chlorophyll content in the dark-green cultivar. The spectrum enhanced with blue light had positive influence on most of the parameters under analysis in butter lettuce cultivars. These cultivars were also characterised by the highest absorbance of blue light.

Microgreens are environmentally friendly and have health benefits in addition to their basic nutritional contents. The effect of white (W), white–blue (W + B), and white–red (W + R) light on the bioactive compounds, nutrient composition, and antioxidant potential of red and white cabbage microgreens were investigated using light-emitting diodes (LEDs). The results showed that protein, fat, ash, chlorophylls, and carotenoids were the highest in microgreens under W light, while phenolic compounds were highest in microgreens under W + B light. Supplementation with white light, as well as red or blue light, resulted in higher levels of sugars and total fiber in both white and red microgreens. Twenty-six and thirty-three phenolic compounds were identified in white and red cabbage microgreens, respectively. The identified phenolics belonged to three classes, including phenolic acids, flavonols, and anthocyanins. The antioxidant potential of both cabbage microgreens was determined by four methods (ABTS, DPPH, ORAC, and FRAP). It was found that the highest antioxidant potential was observed in microgreens grown under the W + B light combination. On the other hand, the W + R light combination increased the content of β-sitosterol and campesterol. The results may be helpful in the selection of the type of LED lighting that determines the high nutritional and health-promoting potential of white and red cabbage microgreens.

Microgreens are becoming increasingly popular both as horticultural crops and as vegetables consumed by humans. They are classified as foods of high nutritional value. Twenty-eight microgreens crops were grown in a growth chamber under fully controlled conditions in order to determine how different light treatments affected their growth rate. The plants were grown under three light sources emitting red/blue ratios of about 6.7, 0.6, and 1.6 units (Red light, Blue light, and R + B light, respectively). Apart from that, the spectrum contained 10% yellow and orange light and 10% green light. The fresh weight of the plants ranged from 8 (perilla) to 1052 mg (nasturtium), whereas the length ranged for the same plants from 2.0 to 26.2 cm. The nasturtium was particularly strongly distinguished from the other species by the high values of its biometric parameters. The fresh mass of most of the other microgreens ranged from 20 to 100 mg, whereas their height ranged from 5 to 8 cm. Red light caused a significant increase in the fresh and dry weights of more than half of the species. The light spectrum had a lesser influence on the length of the plants. The research results showed considerable differences in the dynamics of growth of commonly cultivated microgreens.

The main focus of the study was to determine the content of phenolic acids, flavonoids, and organic acids in the flowers of Tagetes patula ‘Petite Gold’ and ‘Petite Orange’. The growth of the plants was assessed depending on the cultivation conditions. The above plants were illuminated with white light, whereas the ‘Petite Gold’ ones with white light enhanced with blue or red light. Both cultivars grew in a two-level-mineral compounds organic substrate. The research showed that the French marigold flowers were rich in phenolic compounds and organic acids. The ‘Petite Gold’ flowers had more bioactive compounds compared with the ‘Petite Orange’ flowers. Three flavonoids, 10 phenolic acids and seven organic acids were found in the ‘Petite Gold’ flowers. The artificial lighting used during the cultivation of the plants showed diversified influence on the content of organic compounds in their flowers. The measurements of the plants’ morphological traits and the number of inflorescences showed that illumination with red light resulted in a better effect. Large plants with numerous inflorescences grew in the substrate with a lower content of nutrients.

The aim of this research was to study the physiological and biochemical responses of pelargonium growing in saline substrate. Salt stress caused an increase of sodium and chlorine, and decrease potassium ions concentrations in pelargonium leaves depending on their level in peat substrate. About 4–16-fold increase of sodium, 4–6-fold increase of chlorine were found in leaves of plants growing in substrate treated with the lowest (452 mg dm⁻³) and highest (2992 mg dm⁻³) NaCl doses, respectively. The concentration of potassium ions decreased by 20 to 27 % in leaves of plants growing in substrate supplemented with NaCl doses from 1976 to 2992 mg dm⁻³, respectively. However, lower doses of sodium chloride did not affect the content of potassium ions in pelargonium leaves. The increasing salinity of substrate after the addition of 960–2992 mg NaCl dm⁻³ caused the reduction of plant fresh matter in the range of 25–65 %, plant height 10–37 %, and leaf area 15–55 %. There were no changes in relative water content (RWC) and no signs of damage in the form of necrotic spots for any of the used salt concentrations. The content of chlorophyll pigments decreased proportionally to salt concentration, but the content of carotenoids did not change. Maximum photochemical activity of PSII (F _v/F _m) was reduced only in plants growing at the highest dose of NaCl. Proline and anthocyanin levels increased in response to elevated NaCl concentration. At the highest dose of NaCl proline level increased by 30 % while the content of anthocyanins increased about 2.5-fold in relation to the control. It can be assumed that proline and anthocyanins accumulated in pelargonium leaves may be responsible for the amelioration of the adverse effects of salt stress. The results revealed that the investigated pelargonium ‘Survivor Dark Red’ is somewhat tolerant to salinity and it can be cultivated in substrate and soil polluted with NaCl at the level lower than 1976 mg dm⁻³.