Effects of Green Light Deprivation and Red-to-Blue Ratio on Growth, Mineral Content, and Pigments in Salvia officinalis L. and Cannabis sativa L.

Zinc (Zn) is an essential micronutrient for plant growth, serving as a co-factor in enzymatic processes and pigment biosynthesis. In horticultural crops such as lettuce, Zn fertilization is increasingly relevant for optimizing yield and nutritional quality. In this study, a greenhouse pot experiment was conducted using Lactuca sativa L. cv. Romana Verano (Ramiro Arnedo) to evaluate the effects of four Zn sources with contrasting physio-chemical properties—ZnSO4, a synthetic chelate containing DTPA, EDTA, and HEDTA, a Zn–lignosulphonate complex, and ZnO nanoparticles—applied to soil at rates of 15, 30, 60, and 120 mg Zn·kg−1. Morphometric traits, photosynthetic pigmentation, and photosystem performance were assessed to determine differences in plant response. Results showed that low to moderate Zn supply (15–60 mg Zn·kg−1) maintained growth, leaf number, stem diameter, and biomass without significant changes compared to the control. In contrast, the highest dose (120 mg Zn·kg−1), particularly in chelated forms, led to reductions in growth and yield exceeding 80%, reflecting supra-optimal effects. Although lignosulphonate and nanoparticles sources lowered soil Zn availability, they did not affect lettuce growth or yield, indicating their potential as safer agricultural alternatives to conventional Zn fertilizers. Photosynthetic efficiency, measured through chlorophyll fluorescence and electron transport activity, was positively modulated by adequate Zn levels but declined at excessive concentrations. These findings highlight that Zn efficiency strongly depends on its chemical form and applied dose, providing practical insights for optimizing Zn fertilization strategies in lettuce and other horticultural crops.

Controlled environment agriculture (CEA) enables precise regulation of plant physiological processes through environmental control. Among these, the spectral composition of photosynthetically active radiation (PAR), particularly the proportion, dose, and duration of blue light exposure, has a strong effect in enhancing plant nutritional quality. This study investigated how end-of-production (EoP) light spectrum (PAR vs. PAR with high blue portion) and application mode (daily continuous for 18h vs. 18h plus 2-h nighttime exposure) affect the growth, morphology and nutritional quality of three red leaf lettuce cultivars (Lactuca sativa var. crispa 'Xandra', 'Alaine' and 'Haflex'). Plants grown in climate-controlled conditions for 29 days, were exposed to four light treatments (Ctrl, HB, Night, NightB) with a Daily Light Integral (DLI) of 24.3molm-2 d-1 during the final seven days. Light spectrum and application mode significantly affected the three lettuce cultivars. Plants treated with continuous high-blue light (HB) had the lowest values for shoot height, leaf area and biomass, but greatest values for pigment content, antioxidant activity and leaf nitrate accumulation. Short-duration, nighttime blue light application (NightB) improved anthocyanins, phenolics and antioxidant activity without yield loss, achieving the highest blue light use efficiency for anthocyanins (BLUECYA) and biomass (BLUEFW). Cultivar-specific responses were evident, with 'Haflex' exhibiting greater yield, rapid anthocyanin response and lower nitrate accumulation, highlighting the potential for genotype-tailored light strategies in CEA. These results demonstrate that concentrated blue light, when applied as short duration supplementation during the dark phase, can be a viable strategy for enhancing visual and nutritional quality of salad leaves with contained energy expense in commercial plant factories.

To observe variation in growth performance, antioxidant activities, and nutritional quality of Moringa oleifera, we exogenously applied benzyl amino purine (BAP), ascorbic acid, and moringa leaf extract (MLE) to moringa plants at three field capacity levels, 100, 75, and 40% in a completely randomized design with three replications. We observed a decrease in growth, chlorophyll a and b, total phenolic contents, antioxidant activities, crude protein, and mineral contents of moringa leaves at 100 and 40% field capacity in comparison with 75% field capacity. BAP best improved growth performance of moringa plants, improving shoot length, root length, number of leaves and photosynthetic pigments, followed by MLE at 75% field capacity, while moringa plants showed reduced growth at 40% field capacity which was increased by BAP and MLE foliar application. Maximum contents of gallic acid, p-coumaric acid and sinapic acid were found in moringa leaves when the plants were sprayed with ascorbic acid while p-hydroxybenzoic acid and caffeic acid were maximally increased under 75% field capacity when the plants were subjected to BAP followed by MLE. The lowest and highest crude protein, calcium, potassium, magnesium, and phosphorous contents were recorded under 40 and 75% field capacity, with MLE impro-ving these contents under both conditions. It can safely be concluded that moringa plants showed retarded growth under 100 and 40% field capacity, and that the effects of deficit in nutritional quality were mitigated by applying BAP and MLE. Among these two plant growth regulators, MLE can be preferred being a natural source.

Controlled environment agriculture is a promising solution to address climate change and resource limitations. Light, the primary energy source driving photosynthesis and regulating plant growth, is critical in optimizing produce quality. However, the impact of specific light spectra during night interruption on improving phytochemical content and produce quality remains underexplored. This study investigated the effects of red (peak wavelength at 660 nm) and far-red night interruption (peak wavelength at 730 nm) on photosynthetic efficiency, biomass distribution, and phytochemical production in Italian basil (Ocimum basilicum L.). Treatments included red light, far-red light, a combination of both, and a control without night interruption. Red light significantly increased chlorophyll a by 16.8%, chlorophyll b by 20.6%, and carotenoids by 11%, improving photosynthetic efficiency and nutritional quality. Red light also elevated anthocyanin levels by 15.5%, while far-red light promoted flavonoid production by 43.56%. Although red light enhanced biomass, the primary benefit was improved leaf quality, with more biomass directed to leaves over roots. Far-red light reduced transpiration, enhancing post-harvest water retention and shelf life. These findings demonstrate that red and far-red night interruption can optimize phytochemical content, produce quality, and post-harvest durability, offering valuable insights for controlled environment agriculture. Future research should focus on refining night interruption light strategies across a broader range of crops to enhance produce quality and shelf life in controlled environment agriculture.

Micronutrient malnutrition, particularly selenium (Se) deficiency, remains a major challenge. Controlled environment agriculture (CEA) and totally controlled environment agriculture (TCEA) systems offer innovative platforms for resource-efficient food production and nutritional enhancement through precise environmental regulation. Among the available agronomic strategies, Se biofortification has proven to be highly effective in improving the Se-related nutritional and functional quality of vegetables and herbs. Concurrently, light-emitting diode (LED) technologies facilitate the dynamic control of spectral quality, intensity and photoperiod to optimize photosynthesis and secondary metabolism. This review summarizes the current evidence regarding the combined effects of Se biofortification and LED spectral management on plant physiology, mineral nutrition and bioactive compound accumulation. Research indicates that appropriate Se concentrations, typically in the micromolar range, enhance antioxidant activity, phenolic and flavonoid content and stress tolerance, whereas excessive Se levels induce phytotoxic responses. LED light spectra, particularly the red-to-blue ratio, have been shown to regulate Se concentration, translocation and nitrate metabolism, thereby influencing both growth and nutritional quality. The integration of Se biofortification with optimized lighting regimes enhances crop yield stability, resource-use efficiency and Se-driven nutritional attributes in hydroponic systems, microgreens and baby-leaf vegetables. Despite these advancements, substantial knowledge gaps persist regarding Se speciation, metabolic regulation under different light spectra and post-harvest bioavailability. Future research should integrate omics technologies, high-resolution analytics and dynamic light modelling to elucidate Se–light interactions at the molecular and physiological levels. This integration represents a decisive step towards reproducible and economically viable Se biofortification protocols applicable to next-generation indoor farming. Significance of this study What is already known on this subject? Biofortification of crops with essential micronutrients, such as selenium (Se), is an effective strategy for enhancing nutritional quality and human health. Controlled environment agriculture (CEA) systems, using light-emitting diode (LED) technologies, enable precise control of spectral quality, intensity and photoperiod, which are known to influence nutrient uptake, redox regulation and secondary metabolism. However, most studies have examined Se nutrition and light quality as separate factors without fully exploring their combined physiological and biochemical effects in controlled environments. What are the new findings? This review provides an integrated synthesis of how LED spectral management, particularly variations in the red-to-blue (R:B) ratio, affects Se uptake, translocation and metabolism in hydroponically and indoor-grown crops. This highlights that optimized Se concentrations (2–10 µmol L −1 ) combined with balanced R:B light spectra increase antioxidant enzyme activity, phenolic biosynthesis and nitrate reduction while maintaining the yield. This work also identifies key gaps in the current research, including Se speciation, genotype-dependent responses and the influence of dynamic or polychromatic light regimes. What is the expected impact on horticulture? Integrating Se biofortification with LED spectral optimisation in CEA and TCEA systems offers a practical pathway for producing high-quality micronutrient-enriched crops in vertical and urban farms. These findings provide a framework for designing standardized and resource-efficient cultivation strategies that enhance crop value and nutritional integrity across species and developmental stages.

Under light-limiting conditions, many ornamental greenhouse-grown plants show undesired morphological characteristics, such as plant elongation (hypocotyl and epicotyl length) and low dry mass, which reduce plant quality. Research has shown that use of plant growth regulators (PGRs) and changes in both light intensity and spectral composition can reduce these undesired characteristics. However, little is known about the role of the combined effects of supplemental lighting and PGRs on the production of ornamental seedlings. The objective of this study was to characterize the combined and independent effects of light intensity, spectral composition, and PGR applications on the greenhouse production of ornamental transplants. Petunia (Petunia × hybrida), geranium (Pelargonium × hortorum), pansy (Viola × wittrockiana) and dianthus (Dianthus chinensis) were grown for 32–42 days under three supplemental light (SL) treatments: 1) high-pressure sodium (HPS), 2) light-emitting diodes (LEDs) with a 6 blue (B):5 green (G):89 red (R) (percent photon flux ratio), and 3) LEDs with 19B:81R (100 μmol m−2 s−1, 18 h photoperiod for all treatments). A control (No SL) was also included. In addition, a portion of plants were also sprayed with the paclobutrazol PGR (PBZ and No PBZ). The synergistic effects of the combination of PBZ and supplemental lighting resulted in the most compact plants, caused by a reduction in plant height by PBZ and an increase in dry mass by SL. However, PBZ reduced shoot dry mass of most plant species and light combinations. Plant compactness was greater under the 6B:5G:89R LED composition for petunia and when combined with PBZ for geranium than for plants under HPS lighting. Root dry mass of petunia, geranium, and pansy plants increased in response to SL compared with no SL by 2.4–5.7-fold. Results from the two LED spectra were unexpected; plants under 6B:5G:89R were more compact (petunia, geranium), had higher anthocyanin concentrations (petunia), were shorter (petunia, pansy, dianthus) and had less leaf area (petunia, pansy, dianthus) than plants in the SL treatment with a higher B and lower G PF (19B:81R). Supplemental lighting and PBZ can be used in conjunction or independently to improve plant morphology. The increased light from SL provided the most benefits by improving dry mass, compactness, and leaf number for most plant species. However, when PBZ was used in combination with SL, plant compactness increased for some species. The spectral composition of SL had an impact on plant growth and morphology, warranting additional research on plant responses to small changes in the spectral composition of SL.

There is a growing interest in cultivating pakchoi under controlled environment agriculture. However, research on establishing the ideal environmental conditions for growing pakchoi in plant factories remains insufficient. Therefore, in this study, we investigated the optimal red-to-blue light ratio for enhancing pakchoi plants’ nutritional quality and growth. Five light treatments (B, R2B1, R4B1, R8B1, and R) were employed in our study, while white light (W) provided by fluorescent lamps was served as the control. The cultivars used were ‘Jingguan No. 1′, a green pakchoi, and ‘Ziguan No. 1′, a red pakchoi. After 20 days of treatment application, we observed significant improvements in dry weight and leaf area in green and red pakchoi plants under treatment R. Specifically, dry weight increased by 14.8% in green pakchoi and 26.7% in red pakchoi, while leaf area increased by 41.8% in green pakchoi and 81.1% in red pakchoi compared to the control treatment. Additionally, treatment R2B1 promoted net photosynthetic rate (Pn) in red pakchoi plants and enhanced stomatal conductance (Gs), intercellular CO2 concentration (Ci), and transpiration rate (Tr) in both pakchoi varieties. Treatment R4B1 facilitated the accumulation of photosynthetic pigments in pakchoi cultivars. On the other hand, the control treatment was found to be more conducive to the accumulation of glucosinolate concentration (GSc) in both red and green pakchoi cultivars. Notably, the concentrations of vitamin C (Vc) and soluble sugar in green pakchoi plants under treatment R4B1 increased by 78.5 and 31.4%, respectively, compared with those under control treatment. Similarly, the concentrations of Vc, soluble sugar, and anthocyanin in red pakchoi plants under treatment R2B1 were increased by 31.6, 177.8, and 114.4%, respectively, compared with those under the control treatment. These findings indicate that different pakchoi varieties exhibit distinct responses to different light-quality combinations.

Simultaneous exposure of sulphur and calcium hinder As toxicity: Up-regulation of growth, mineral nutrients uptake and antioxidants system

Soil contamination with heavy metals has become a worldwide problem, leading to losses in agricultural yield and hazardous human health effects as they enter the food chain. The present investigation was undertaken to examine the influence of cadmium (Cd2+) on the wheat (Triticum aestivum L.) plant. Cd2+ accumulation and distribution in 3-wk-old seedlings grown in nutrient medium containing varying concentrations of Cd2+ (control, 0.25, 0.50, 1.0, 2.5, and 5.0 mg/L) was monitored. The effect of varying Cd2+ concentrations up to 21 d on biomass productivity, plant growth, photosynthetic pigments, protein, amino acids, starch, soluble sugars, and essential nutrients uptake was studied in detail to explore the level up to which the plant can withstand the stress of heavy metal. Plants treated with 0.5, 1.0, 2.5, and 5.0 mg/L Cd2+ showed symptoms of heavy-metal toxicity as observed by various morphological parameters which were recorded with the growth of plants. The root, shoot-leaf length and the root, shoot-leaf biomass progressively decreased with increasing Cd2+ concentration in the nutrient medium. Cd2+ uptake and accumulation was found to be maximum during the initial growth period. Cd2+ also interfered with the nutrients uptake, especially calcium (Ca2+), magnesium (Mg2+), potassium (K+), iron (Fe2+), zinc (Zn2+), and manganese (Mn2+) from the growth medium. Growth reduction and altered levels of major biochemical constituents such as chlorophyll, protein, free amino acids, starch, and soluble sugars that play a major role in plant metabolism were observed in response to varying concentrations of Cd2+ in the nutrient medium. In the present study, the effects of Cd2+ on growth, biomass productivity, mineral nutrients, chlorophyll biosynthesis, protein, free amino acid, starch, and soluble sugars in wheat plants was estimated to establish an overall picture of the Cd2+ toxicity at structural and functional levels.

In recent years, consumption of herb products has increased in daily diets, contributing to the prevention of cardiovascular diseases, chronic diseases, and certain types of cancer owing to high concentrations of phytonutrients such as essential oils and phenolic compounds. To meet the increasing demand for high quality herbs, controlled environment agriculture is an alternative and a supplement to field production. Light is one of the most important environmental factors influencing herb quality including phytonutrient content, in addition to effects on growth and development. The recent development and adoption of light-emitting diodes provides opportunities for targeted regulation of growth and phytonutrient accumulation by herbs to optimize productivity and quality under controlled environments. For most herb species, red light supplemented with blue light significantly increased plant yield. However, plant yield decreased when the blue light proportion (BP) reached a threshold, which varied among species. Research has also shown that red, blue, and ultraviolet (UV) light enhanced the concentration of essential oils and phenolic compounds in various herbs and improved antioxidant capacities of herbs compared with white light or sunlight, yet these improvement effects varied among species, compounds, and light treatments. In addition to red and blue light, other light spectra within the photosynthetically active region—such as cyan, green, yellow, orange, and far-red light—are absorbed by photosynthetic pigments and utilized in leaves. However, only a few selected ranges of light spectra have been investigated, and the effects of light quality (spectrum distribution of light sources) on herb production are not fully understood. This paper reviews how light quality affected the growth and phytonutrient accumulation of both culinary and medicinal herbs under controlled environments, and discusses future research opportunities to produce high quantity and quality herbs.

Alteration of growth, phenology, and yield of lily flowers through the synergetic effect of light spectra and endophytic bacterial priming

Shoot uptake of mineral nutrients (Ca, Cu, Fe, K, mg, Mn, P, S, Zn) by Agrostis stolonifera L. was compared with Festuca ovina L. under wet and dry cycles. Such conditions are typical for A. stolonifera sites, whereas F. ovina is growing mostly on consistently drier and better-drained soils. Plants were grown in a glasshouse, at controlled temperature and light conditions, using two moisture regimes, one constant at 60% WHC (water holding capacity), one wet/dry fluctuating between 35 and 100% WHC. Above ground and total biomass production was lower under wet/dry treatment than at constant water regime in F. ovina, but did not differ between regimes in A. stolonifera. Shoot uptake of most elements was severely reduced in F. ovina at the wet/dry regime. Shoot uptake and concentrations of most elements studied (Cu, K, Mn, P, S, Zn) were lower (p<0.05) under wet/dry treatment than at constant regime in A. stolonifera and tended to be lower also of Fe and Mg. Differences in biomass production observed are consistent with field evidence that A. stolonifera grows in sites which are periodically flooded but may become quite dry during other periods, and that F. ovina is limited to sites which are consistently drier and better drained. Evidence from the present study, however, does not support any view that alternating wet and dry cycles, as typical of A. stolonifera field sites, would be beneficial to nutrient acquisition of this species but that biomass production may develop normally at the lower uptake of most mineral nutrients measured under the wet/dry regime. Such regimes are decidedly unfavourable to both growth and nutrient acquisition of F. ovina.

In soilless cultivation, plants are grown with nutrient solutions prepared with mineral nutrients. Beneficial microorganisms are very important in plant nutrition. However, they are not present in soilless culture systems. In this study we investigated the impact of introducing Plant Growth Promoting Rhizobacteria (PGPR) as an alternative to traditional mineral fertilizer in hydroponic floating lettuce cultivation. By reducing mineral fertilizers at various ratios (20%, 40%, 60%, and 80%), and replacing them with PGPR, we observed remarkable improvements in multiple growth parameters. Applying PGPR led to significant enhancements in plant weight, leaf number, leaf area, leaf dry matter, chlorophyll content, yield, and nutrient uptake in soilles grown lettuce. Combining 80% mineral fertilizers with PGPR demonstrated a lettuce yield that did not significantly differ from the control treatment with 100% mineral fertilizers. Moreover, PGPR application improved the essential mineral concentrations and enhanced human nutritional quality, including higher levels of phenols, flavonoids, vitamin C, and total soluble solids. PGPR has potential as a sustainable substitute for synthetic mineral fertilizers in hydroponic floating lettuce cultivation, leading to environmentally friendly and nutritionally enriched farming.

استفاده از پتانسیل میکروبی خاک از جمله قارچ های میکوریز آربوسکولار (AMF)برای بهبود رشد و تغذیه گیاه بطور گسترده ای مورد توجه قرار گرفته است. این مطالعه به منظور بررسی تأثیر قارچ های میکوریز آربوسکولار بر رشد و درصد مواد مؤثره نعناع فلفلی تحت شرایط گلخانه ای در قالب طرح کاملا تصادفی با 4 تیمار قارچ میکوریز آربوسکولار انجام شد. تیمارهای تلقیحی شامل 1) شرایط بدون تلقیح (C)، 2) گلوموس فسیکولاتوم (Gf)، 3) گلوموس اینترارادیسز (Gi) و 4) گلوموس موسه (Gm) بودند. در پایان دوره رشد برخی پارامترهای رشدی شامل ارتفاع، قطر ساقه، تعداد شاخه جانبی، تعداد برگ، وزن تر و خشک برگ و همچنین درصد مواد مؤثره و درصد کلنیزاسیون ریشه نعناع فلفلی اندازه گیری شدند. نتایج نشان داد تلقیح با قارچ های میکوریز آربوسکولار اثر معنی داری (05/0P≤)، بر روی پارامترهای اندازه گیری داشته است. تلقیح با قارچ های میکوریز آربوسکولار، ارتفاع گیاه، قطر ساقه، تعداد شاخه های جانبی، تعداد برگ، ماده تر و خشک برگ، درصد کلونیزاسیون ریشه و محتوی (25 درصد) و عملکرد اسانس (28 درصد) را افزایش داد. منتول، منتون و 1و 8-سینئول بالاترین فراوانی را در مواد موثره نعناع تشکیل دادند. تأثیر قارچ-های میکوریز آربوسکولار بر وزن خشک ریشه و درصد کلونیزاسیون ریشه معنی دار (05/0P≤) بود. بیشترین و کمترین درصد کلونیزاسیون ریشه (به ترتیب 47 و 0 درصد) در گیاهان تلقیح شده با Gf و تیمار شاهد مشاهده گردید.

Basil (Ocimum basilicum L.) microgreens are valued for their high phenolic content and antioxidant capacity, which can be modulated under controlled environment agriculture (CEA). This study investigated the combined effects of three light-emitting diode (LED) light intensities (200, 250, and 300 µmol m-2 s-1) and three nutrient solution concentrations (basic, enriched, and diluted) on biomass accumulation, phytochemical composition, antioxidant activity, and photosynthetic pigments in basil microgreens. The fresh weight (FW), dry weight (DW), dry matter content (DM), total phenolic content (TPC), antioxidant capacity (DPPH, ABTS, FRAP), and pigment levels were evaluated across nine treatment combinations. Biomass accumulation was primarily driven by nutrient availability; the highest FW (18.23 g 100 cm-2) was recorded under low light with elevated nutrients and was 133% higher than under high light combined with reduced nutrient supply. In contrast, the DM content increased under high light and low nutrients, reaching about 9%, which was 112% higher than in the lowest DM treatment. Increasing light intensity markedly resulted in phenolic accumulation and antioxidant activity. The highest TPC (28.39 mg g-1 DW) observed under 300 µmol m-2 s-1 with reduced nutrients was approximately 97% higher than that under 200 µmol m-2 s-1 with basic nutrition. Under the same conditions, DPPH, ABTS, and FRAP antioxidant activities increased by 54%, 54%, and 81%, respectively. Photosynthetic pigment responses to light and nutrient treatments were limited, with statistically significant differences observed mainly for chlorophyll b and the chlorophyll a/b ratio, while chlorophyll a and carotenoids remained largely unchanged. Principal component analysis separated high-light treatments by elevated phenolic-antioxidant profiles and low-light treatments by higher biomass and pigment levels. Overall, high light combined with moderate nutrient limitation promotes phenolic and antioxidant enrichment in basil microgreens, representing a quality-modulating strategy rather than a fully optimized cultivation regime.