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Light and nitrogen are the main factors commanding horticulture production. Therefore, this study aims at evaluating the effects of two different greenhouse cover films (clear-Film A and diffuse light-Film B) on yield and nutritive value of a ready-to-eat salad lamb’s lettuce (Valerianella locusta L.), grown under several nitrogen regimes (no nitrogen [N0], sub-optimal [N25] and optimal N fertilization [N50] corresponding to 0, 25 and 50 kg ha-1 , respectively). The combination N50 and Film B boosted SPAD index by 10.3% and yield by 91.9% compared to N0 × Film A. Concerning antioxidant activity and bioactive compounds, only total ascorbic acid was positively affected by Film B (9.4%), while there was no effect of this cover film on carotenoids and chlorophyllous pigments, which increased along the increment of nitrogen rates. Nitrate content in leaves was influenced by both factors and it showed increasing values, when nitrogen doses increased, reaching the highest value under N50-Film B conditions (3312.3 mg kg-1 fw). Our study showed that in the Mediterranean area, the use of greenhouse diffuse light film improved lamb’s lettuce yield, but on the other hand incurred significant increase in nitrate level, nonetheless remaining constantly under the legal threshold imposed by the commission regulation (EU). Secondary metabolites, such as total phenols and carotenoids, showed similar values under both films, instead the diffuse light film improved total ascorbic acid content.

Light and nitrogen strongly affect the growth, yield, and quality of food crops, with greater importance in green leafy vegetables for their tendency to accumulate nitrate in leaves. The purpose of this research was to explore the effect of two greenhouse films (Film A and B) on yield, and quality of spinach grown under different nitrogen regimes (not fertilized—N0%, sub-optimal N dose—N50%, optimal N dose—N100%). Film A and Film B were used as clear and diffused light films, with 75% and 87% thermicity, and 85% and 90% total transmittivity, respectively, where only Film B had a UV-B window. Film B elicited an increase in yield (22%) and soil–plant analysis development (SPAD) index (4.6%) compared to the clear film, but did not affect chlorophyll a, b, and total chlorophyll content. In addition, the diffuse film significantly decreased ascorbic acid in the crop but had no effect on lipophilic antioxidant activity and phenols content, but decreased ascorbic acid content. Finally, nitrate content was strongly increased both by nitrogen dose (about 50-fold more than N0%) and greenhouse films (about six-fold higher under diffuse light film), but within the legal limit fixed by European Commission. Therefore, irrespective of N levels, the use of diffuse-light film in winter boosts spinach yield without depressing quality.

The current research elucidated the agronomical, physiological, qualitative characteristics and mineral composition of lettuce (Lactuca sativa L. var. longifolia) after treatments with a beneficial fungus Trichoderma virens (TG41) alone or in combination with a vegetal biopolymer-based biostimulant (VBP, &lsquo, Quik-link&rsquo, ). The experiment consisted of lettuce plants grown in three N conditions: sub-optimal (0N kg ha&minus, 1), optimal (70N kg ha&minus, 1), and supra-optimal (140N kg ha&minus, 1) N levels. Lettuce grown under 0N fertilization showed a significant increase in fresh yield when inoculated with TG41 alone (45%) and a greater increase with TG41 + VBP biostimulant (67%). At 48 days after transplanting, both the TG41 alone or TG41+VBP biostimulant induced higher values of CO2 assimilation in comparison to the control. The mineral concentrations in leaf tissues were greater by 10% for K and 12% for Mg with the TG41+VBP treatments compared to the untreated lettuce. The lettuce plants receiving either TG41 alone or TG41+VBP biostimulants had a significantly lower nitrate content than any of the untreated controls. In non-fertilized conditions, plants treated with TG41+VBP biostimulants produced lettuce of higher premium quality as indicated by the higher antioxidant activity, total ascorbic acid (+61%&ndash, 91%), total phenols (+14%) and lower nitrate content when compared to the untreated lettuce.

The nutrient and nutraceutical quality of greenhouse wild rocket is strongly influenced by the light environment and nitrogen fertilization. We investigated the effects of two cover materials, a diffuse light film (Film1) and a traditional clear film (Film2), and three nitrogen regimes, no N supply (N0) and sub-optimal (N1) and optimal (N2) doses, also in combination with a biostimulant (Stimolo Mo), on the mineral composition, antioxidant properties and chlorophyll and carotenoid content of rocket plants grown in the autumn–spring cycle. The leaf concentration of most of the minerals was higher under Film1 compared to Film2. In general, K, Ca, Mg and Na were higher, and S was lower in the presence of N supply, and the addition of the biostimulant promoted the mineral uptake. Under Film1, the hydrophilic antioxidant activity (HAA) was higher in some harvests, and the ABTS antioxidant activity (ABTS AA) in the first one, while always lower afterward, than under Film2. Nitrogen fertilization did not affect the antioxidant activity, while it reduced the content of total phenols and ascorbic acid. The biostimulant application increased ABTS AA at the optimal N dose and reduced total phenols in unfertilized plants. Both the diffuse light and the N supply inhibited the synthesis of ascorbic acid, while N fertilization and the biostimulant promoted the synthesis of chlorophylls. The experimental treatments exerted variable effects over time and significant interactions with the harvest period were found for many of the investigated parameters.

Featured Application: The results of the present work provide useful insights into the response of Diplotaxis tenuifolia L. plants to salinity stress and biostimulant application under successive crop cycles. Considering the complex effects of biostimulants on vegetable crops, providing new information regarding the positive effects of this agronomic practice under salinity stress and variable growing conditions will be useful for farmers and crop production stakeholders in their efforts to address the increasing soil salinization and degradation of the quality of irrigation water. The availability of irrigation water of good quality is decreasing due to soil salinization and the deterioration of aquifers. Moreover, ongoing climate change severely affects crop production and necessitates the intensification of cropping systems in order to ensure food security at a global scale. For this purpose, the aim of the present study was to evaluate the mitigating effects of two natural biostimulants on Diplotaxis tenuifolia L. plants cultivated at different salinity levels (EC of 0 dS m−1, 2 dS m−1, 4 dS m−1, and 6 dS m−1) and harvested at six consecutive cropping cycles. The tested factors showed a varied combinatorial effect on the tested parameters. These findings indicate the importance of considering growing conditions and cropping periods when applying biostimulants in D. tenuifolia plants under salinity stress. Antioxidant activity and bioactive compounds, such as total phenols, carotenoids, and total ascorbic acid, were variably affected by salinity, biostimulant application, and harvesting time, while mineral profile was also affected by the tested factors depending on the combination of factors. Finally, nitrate content showed decreasing trends with increasing salinity, while biostimulant application resulted in the higher accumulation of nitrates compared to the untreated plants. Although biostimulant application seems to alleviate the negative effects of salinity stress, the effect of growing conditions, as indicated by successive crop cycles, is also important for the response of D. tenuifolia plants to saline conditions and biostimulant application.

Citrullus colocynthis L. is a wild watermelon, commonly named bitter melon or bitter apple, that naturally grows in arid regions of India among other hot arid areas of the world. Its non-edible fruits contain certain phytochemicals of therapeutic and nutraceutical value. The effectiveness of biopesticide formulations that are known to possess insecticidal properties was tested. This is the first botanical pesticide formulation developed from C. colocynthis, named “Thar Jaivik 41 EC”. The phytochemicals of C. colocynthis seed were identified using GC-MS/MS, and a total of 59 constituents were identified, of which seven have significant insecticidal properties: n-hexadecanoic acid; octadecanoic acid; dotriacontance; 9, 12-octadecadienoic acid (Z,Z); 9, 12-octadecadienoic acid (Z,Z)-, methyl ester; 6-octadecenoic acid, methyl ester; and hexatriacontane. Among the different levels of tested concentrations, “Thar Jaivik 41 EC” was found most effective at 3 mL L−1 for managing various insect pests such as pod borer (Helicoverpa armigera) and aphid (Toxoptera citricida) through repellent, deterrent, antifeeding action and by causing respiration abnormalities. Moreover, it caused the least harm to natural enemies such as coccinellids at this concentration. The phytotoxicity response of “Thar Jaivik 41 EC” on tested crops revealed that it is highly safe for plants, showing no toxicity symptoms when applied at higher doses than the recommended one (3 mL L−1). Integration of the “Thar Jaivik 41 EC” formulation in agriculture would help to safeguard farmers’ benefits, such as reduced pest levels, improved food safety and quality of products, which would allow them to fetch higher prices, as well as provide intangible benefits to the consumers and environment.

Nitrate is the principal source of nitrogen for most higher plants. Particularly leafy vegetables require large quantities of nitrate fertilizer to attain maximal yields. The crop yield and quality as well as nitrate accumulation in leafy vegetables depends upon many preharvest factors such as genetic materials, agronomical and environmental factors. Three greenhouse experiments were carried out in order to assess the effects of preharvest factors (cultivars, plant density and N dose) on yield and quality of spinach (Spinacia oleracea L.). In the first trial four spinach cultivars were compared in terms of yield and quality attributes. The marketable yield of the four cultivars tested was in the following order: ‘Tasman’ = ‘Kookaburra’ > ‘Platypus’ = ‘Regiment’. No significant differences among cultivars were observed for the βcarotene, vitamin C and nitrate contents. In the second trial, treatments were defined by four plant densities (800,000; 1,000,000; 1,200,000; 1,500,000 seeds ha-1). The lowest marketable yield was observed under the lowest plant density, whereas no significant difference was recorded between the other treatments. The highest leaf dry matter, K, and nitrate contents were recorded at 1000000 seeds ha-1. In the third experiment we evaluated the effects of four N fertilizer doses (0, 75, 150 and 225 kg ha-1) on crop performance. Marketable yield increased quadratically with increasing N application with the highest values recorded at both 150 and 225 kg ha-1 indicating a luxury consumption of the nutrient at 225 kg ha-1. Finally, the highest protein and nitrate contents were observed at 225 kg ha-1 of N.

Microgreens appeared in the human diet as a decoration of culinary dishes, due to their shape, tenderness and vivid colours. They are currently attracting researchers' attention for their nutraceutical properties. In fact, they were found to be packed with vitamin C, carotenoids and minerals. The genetic aspect is one the most important preharvest factors. Microgreens of the Brassicaceae family are well researched. In our study, six genotypes belonging to the Brassicaceae family: Cress (Lepidium sativum L., 'Curled'), komatsuna (Brassica rapa L. var. perviridis 'Comred F1'), mibuna (Brassica rapa L. subsp. nipposinica 'Japanese greens'), mizuna (Brassica rapa var. japonica 'Greens'), pak choi (Brassica rapa L. subsp. chinensis 'Red Wizard F1'), tastoi (Brassica rapa L. subsp. narinosa), were cultivated in a growth chamber, and analysed to determine colourimetric parameters, nitrate content, minerals, bioactive molecules (chlorophylls, carotenoids, ascorbic acid, total phenols) and antioxidant activity. The results confirmed the hypothesis of genetic variability for the analysed parameters. pak choi and komatsuna had the highest content of macronutrients (P, S, K and Ca). Pak choi had the highest total chlorophylls and total ascorbic acid content. These findings place emphasis on an appealing product like microgreens.

Irrigated agricultural lands are prone to salinity problems which may imperil horticultural crops by reducing growth, yield and even qualitative traits. Eco-friendly approaches such as biostimulant application and in particular protein hydrolysates from vegetal origin are implemented to mitigate salinity stress effects on crops. For this reason, a greenhouse experiment on spinach irrigated with increasing concentrations of saline water (EC = 3 dS m−1 (EC3), 6 dS m−1 (EC6) and 9 dS m−1 (EC9), in addition to non-saline treatment (EC0)) was organized, while plants were subjected to foliar applications of a protein hydrolysate from vegetal origin on a weekly basis. The application of this biostimulant helped mitigate the adverse effects of saline stress, by increasing the SPAD index and total chlorophylls of spinach plants. Yield was significantly boosted under biostimulant treatment in saline conditions and reached the value obtained in control treatment (no biostimulants added) × EC0 in the case of EC 3 and 6 dS m−1. In addition, the number of leaves and plants m−1 was increased under biostimulant treatment, and most importantly the hydrophilic antioxidant activity of spinach, thus a qualitative aspect of great importance was also increased. Such results increase the knowledge on the effects of protein hydrolysates application on an important leafy vegetable and may help growers mitigate saline conditions and maintain high crop yield and high quality of the final product when no other source of irrigation water is available.

Microgreens represent a new generation of food products, commonly used to garnish and embellish culinary dishes, and recently associated with an increasing interest in their nutraceutical and phytochemical profiles. Four Apiaceae species: Pimpinella anisum L. (anise), Anthriscus cerefolium L. (chervil), Carum carvi L. (caraway), and Anethum graveolens L. (dill) were assessed for fresh yield, macro- and microminerals, total chlorophylls, total ascorbic acid, carotenoids, polyphenols, and their antioxidant activity. Anise was the species yielding the most (2.53 kg m−2) and having the highest lutein content (18.4 µg g−1 dry weight (DW)). Chervil and dill were characterized by the highest total ascorbic acid content (~151 mg AA g−1 fresh weight (FW)). The phenolic profile highlighted the presence of five flavonoid derivatives and 12 phenolic acid derivatives, with quinic acid derivatives being the most abundant phenols in the species tested. In addition, anise, caraway, and dill proved to be considerably rich in total polyphenols (~11056 μg g−1 DW). Caraway and dill were characterized by the highest antioxidant activity measured by the DPPH and ABTS methods, whereas the FRAP method revealed caraway as having the highest antioxidant activity. Such results highlight the potential of Apiaceae species as an alternative to other families which are commonly used for microgreens production.

Biostimulants are sustainable inputs that can be used to reduce chemical fertilizers dependency while reinforcing nutrient uptake, yield and quality of crops, and modulate plant metabolic processes. Protein hydrolysates (PHs) are prominent biostimulants that guarantee a reduction in yield loss under sub-optimal nitrogen (N) conditions. On these bases, a new Malvaceae-derived PH product was tested along a commercial legume-derived PH on soilless greenhouse-grown lettuce, to comparatively assess their activity under N depletion conditions (1 mM NO3−). Both PHs increased biometric parameters under optimal but to a lesser extent under depleted N conditions. Legume-derived PH promoted greater Fv/Fm, lutein and β-carotene under optimal N conditions and higher catalase and total phenolic acids. In contrast, Malvaceae-derived PH did not affect phenolic acids but increased leaf concentration of Ca, Mg and catalase while reducing H2O2. Biochemical changes were then evaluated through untargeted metabolomics. Metabolomics showed a hierarchically prevalent effect of the N level, with the PHs showing distinctive reprogramming under optimal and depleted N conditions. Among others, phenylpropanoids were mainly down-accumulated in stressed plants, while (polyunsaturated fatty acids) PUFA accumulated following the application of PHs. Notwithstanding, the severe depletion of N cannot be compensated by PHs treatment since biostimulants are used to complement fertilizers use and not to replace it.

Sweet basil (Ocimum basilicum L.) is one of the most common aromatic herbs cultivated all over the world. It is widely used for its aromatic and culinary purposes. Consumer demand for fresh sweet basil has been on the rise and many farmers of leafy vegetables and aromatic herbs have oriented their production schemes to include basil. The genetic material is a key preharvest factor and the major determinant of variation in yield and quality of leafy vegetables. Another important preharvest factor that may modulate yield and nutritional quality of sweet basil could be the growing medium. The aim of this research was to assess in a multi-factorial approach the effects of two sweet basil cultivars (Napoletano and Genovese) and two substrates (rockwool and an innovative inert substrate, SISAL fiber) on plant growth, marketable yield, nitrogen content and nutritional quality. The plant growth parameters, yield and especially the bioactive compounds were mostly affected by the growing media and to a lesser extent by the genetic material. When averaged over growing media, the highest leaf number was observed in 'Genovese' while an opposite trend was recorded for the leaf area. Irrespective of the sweet basil cultivar, plants grown on rockwool exhibited a higher leaf area, leaf fresh weight and dry biomass compared to those grown on SISAL fiber substrate. Contrarily to crop productivity, sweet basil grown on SISAL was characterized by high levels of lipophilic antioxidant activity, total chlorophyll and carotenoids, whereas no significant effect among treatments were recorded on total phenols. Although the yield reduction with SISAL was quite significant, the basil plants grown on this innovative substrate produced leaves with high concentrations of bioactive compounds. Additional researches should focus on elucidating the Genotype × Substrate interaction in order to select the best combinations.

In the last twenty years, horticulture has focused on producing high-quality food while improving resource use efficiency. The application of nutritional stress is an effective tool to increase the phytochemical content of vegetables while reducing environmental footprint. Microgreens represent an emerging functional food characterized overall by higher levels of phytonutrients than their mature counterparts. The current study examined the effect of using nutrient solution or only distilled water on the nutraceutical performance of lettuce (Lactuca sativa L.) microgreens grown in a peat-based substrate. Our results showed that lettuce microgreens can be effectively grown using only substrate nutrients, incurring a 27% decrease in fresh yield, but a significant increase in total ascorbic acid (+187%), anthocyanins (+35%), and total phenolic acids content (+26%). Of utmost interest, is the near absence of nitrates in water-treated microgreens, which renders this category of fresh vegetables ideal for the production of food dedicated to consumers highly sensitive to nitrates, such as infants. Growing microgreens without providing additional nutrients to those found in a typical peat-based substrate is an important potentiality that adds value to this new class of vegetables and also renders them particularly suitable for home cultivation.

Seed priming is the induction of a particular physiological state in plants by the treatment of natural and synthetic compounds to the seeds before germination, with the aim to boost germination percentage and seedlings performance. The aim of the current research was to assess the influence of three seed priming treatments (control, cold priming and osmo priming) on the total germination percentage and the transplant quality of six vegetable species (artichoke [Cynara scolymus L.], endive [Cichorium endivia L.], fennel [Foeniculum vulgare L.], onion [Allium cepa L.], pepper [Capsicum annuum L.] and tomato [Solanum lycopersicum L.]). The transplants performance was compared in terms of biometric measurements and pigments (chlorophyll and carotenoids). Our results demonstrated that the positive effect of seed priming on total germination was species-dependent. Cold priming makes Cynara scolymus L. seeds reach 65% germination, Cichorium endivia L. seeds 93%, and Allium cepa L. seeds 81%. The osmo priming treatment brings the germination of Capsicum annuum L. seeds to 87%, and the Solanum lycopersicum L. seeds to 83%. Foeniculum vulgare seeds show the highest germination capacity compared to other tested species. Even the morphological traits of the six vegetable transplants were also influenced by the two priming methods in a specific-species manner. Osmo priming increased the total phenols content in Cichorium endivia L. and Solanum lycopersicum L. Finally, In Allium cepa L. both priming treatments reduced chlorophyll b and total chlorophyll content.

High sodium chloride (NaCl) concentration in the irrigation water of greenhouse crops is a typical phenomenon of nursery activities in the south Mediterranean regions and has frequently detrimental effects on plant growth and quality as it may lead to an unbalance of some ions and thus to biochemical and physiological stresses resulting in reduced plant growth, leaf chlorophyll content and net photosynthesis. With the aim to assess the effects of this salt stress on crop responses, a greenhouse cultivation of three potted ornamental shrubs at increasing NaCl concentration (0, 40 and 80 mM) of irrigation water was conducted. Plants of Asteriscus maritimus, Euphorbia × lomi and Murraya paniculata were grown in 7-L containers using a mixture of sphagnum peat, perlite and red soils (1:1:1, v/v/v) under the same irrigation regime for avoiding water stress. Among the three species, the Mediterranean halophyte Asteriscus resulted the most tolerant to salt stress as highest values of many bio-morphological parameters (shoots emission, leaf area, biomass production) were recorded in plants irrigated with 80 mM NaCl, whereas lowest performances were observed in no-treated plants. Euphorbia and Murraya resulted moderately tolerant to salt stress as no significant differences on plant growth and physiological activities were found between control-plants and those irrigated with 40 mM NaCl, while lower values were measured under 80 mM NaCl treatment.

The quantity and quality of wall rocket (Diplotaxis tenuifolia L.) production are strongly influenced by the cultivation system, in particular the protected environment conditions and nitrogen fertilization. In the present research, we tested two greenhouse cover films (Film1: diffuse light; Film2: clear), to verify the effects on yield and nitrate content (a detrimental factor of quality) of rocket leaves, fertilized with optimal (N2) or sub-optimal nitrogen dose (N1), or unfertilized (N0). In addition, we combined the N fertilization with a biostimulant application, declared by the manufacturer as able to reduce nitrate content. Film1 provided a 36% yield increase over Film2 and allowed an increasing production until the V harvest, opposite to what was recorded under Film2, where the yield increased only until the III harvest. Additionally, biostimulant application boosted the yield (+40%), as well as nitrogen fertilization. Both factors had the best performance under Film1, where N1 yield was even equal to N2-Film2. The nitrate content showed a seasonal trend (lower values in spring harvests) and it was boosted by nitrogen (1096, 3696, and 4963 mg/kg fresh weight, for N0, N1, and N2, respectively) and biostimulant application (3924 vs. 2580 mg/kg fresh weight). Therefore, the use of diffuse-light film seems useful to obtain higher yield with a halved N dose as well as in combination with biostimulant application, but the latter did not confirm the capacity to contain nitrate, at least for this crop and in this cultivation system.

The use of biostimulants in modern agriculture has rapidly expanded in recent years, owing to their beneficial effects on crop yield and product quality, which have come under the scope of intensive research. Accordingly, in the present study we appraised the efficacy of two plant-derived biostimulants, the legume-derived protein hydrolysates Trainer® (PH), and the tropical plant extract Auxym® (TPE) on two lettuce cultivars (green and red salanova®) in terms of morpho-physiological and biochemical traits (primary and secondary metabolites). The two cultivars differed in their acquisition capacity for nitrate and other beneficial ions, their photosynthetic and transpiration rates, and their ability to synthetize and accumulate organic acids and protective metabolites. The biostimulant effect was significant for almost all the parameters examined but it was subjected to significant cultivar × biostimulant interactions, denoting a cultivar-dependent response to biostimulant type. Notwithstanding this interaction, biostimulant application could potentially improve the yield and quality of lettuce by stimulating plant physiological processes, as indicated by the SPAD index (leaf chlorophyll index), ACO2 (assimilation rate), E (transpiration), and WUEi (intrinsic water use efficiency), and by increasing concurrently the plant mineral content (total N, K, Ca, Mg) and the biosynthesis of organic acids (malate, citrate), phenols (caffeic acid, coumaroyl quinic acid isomer 1, dicaffeoylquinic acid isomer 1), and flavonoids (quercetin-3-O-glucuronide, quercetin-3-O-glucoside). Biostimulant action may facilitate the bio-enhancement of certain lettuce cultivars that are otherwise limited by their genetic potential, for the accumulation of specific compounds beneficial to human health.

The negative impacts of extreme heat and drought on olive plants have driven the quest for mitigation approaches based on the use of biostimulants, which have proved to be effective in contrasting environmental stresses. The aim of our study was to evaluate the effectiveness of six biostimulants in mitigating high temperature and water stress in young olive trees in terms of vegetative and eco-physiological parameters as well as bioactive compound content. Biostimulants based on glycine betaine and macro- and micro-algae effectively protected the plants from abiotic stress by improving their eco-physiological and vegetative parameters. At the end of the growing season, olive plants were experiencing water deficit which had built up through the summer months. At this time, the glycine betaine-treated plants had a three-fold higher stomatal conductance compared with the control, while plants sprayed with the seaweed mix had a relative water content 33% higher than the control. The kaolin treatment resulted in higher total phenolics and antioxidant activities (DPPH, FRAP and ABTS) in water stress conditions and caused an increase of 238.53 and 443.49% in leaves total polyphenols content in 100% and 50% water regime, respectively. This study showed the effectiveness of biostimulants in mitigating the damage from abiotic stress on young olive trees, by improving some vegetative, eco-physiological and leaf nutraceutical parameters. Further studies are needed to test the efficiency of these biostimulants in open field conditions on olive trees in full production.

Plant factories and high-tech greenhouses offer the opportunity to modulate plant growth, morphology and qualitative content through the management of artificial light (intensity, photoperiod and spectrum). In this study, three Light Emitting Diode (LED) lighting systems, with blue (B, 460 nm), red (R, 650 nm) and mixed red + green-yellow + blue (RGB) light were used to grow parsley microgreens to understand how light quality could change the phenotype and the profile of secondary metabolites. Plants showed altered morphological characteristics and higher amounts of secondary metabolites under RGB LEDs treatment. The results demonstrated that microgreens under red light showed the highest fresh yield, petiole length, coumaric acid content but also the highest nitrate content. Plants under RGB light showed the highest dry matter percentage and highest content of total and single polyphenols content, while blue light showed the highest ascorbic acid and ABTS antioxidant activity. Moreover, microgreens under red light showed more compact leaves with less intercellular spaces, while under blue and RGB light, the leaves displayed ticker spongy mesophyll with higher percentage of intercellular spaces. Therefore, the specific spectral band was able to modify not only the metabolic profile, but also it could modulate the differentiation of mesophyll cells. Light quality as a preharvest factor helps to shape the final parsley microgreens product as a whole, not only in terms of yield and quality, but also from a morpho-anatomical point of view.

Supplementary lighting of specific wavelengths can be used for inducing morphological and physiological responses in different crops, ultimately improving yield and quality. Based on this approach, new greenhouse covering materials are being developed in order to improve the use of sunlight in horticulture. These new-generation greenhouse coverings may incorporate light spectrum modulation agents or fluorescent additives which convert solar UV radiation into visible light. In this work, we tested the agronomical and physiological response of lettuce grown under a greenhouse covered with poly-methyl-methacrylate (PPMA) panels doped with a blend of the rare-earth inorganic material with a photo-luminescent effect. The doped greenhouse elicited a 36% increase in lettuce yield compared to the undoped greenhouse. Chlorophyll and carotenoid content, as well as antioxidant activity and ascorbic acid content, were not affected by greenhouse cover, but the doped panels induced a 22% reduction in total phenolics and a 14% increase in nitrate content in leaves. The greenhouse covering materials also affected the photochemistry of photosynthesis, as the daily fluctuations in both the effective quantum yield (ΦPSII) and the electron transport rate (ETR) were attenuated under the doped greenhouse. Non-photochemical quenching (NPQ) was closely related to the light environment in all experimental conditions, with the highest values at 14:00 h. Our results showed that the red-supplemented light spectrum under the doped greenhouse cover contributed to increased plant growth and yield, with a corresponding effect on the physiology of photosynthesis.

Tomato (Solanum lycopersicum L.) is one of the most consumed vegetables worldwide due to its low caloric intake and high fiber, minerals, and phenolic compounds, making it a high-quality functional food. However, fruit quality attributes can be affected by pre-harvest factors, especially environmental stresses. This research aimed to evaluate the influence of two shading nets (white net −30% and pearl grey net −40% shading degree) on the yield and phytochemical profile of tomato fruits grown in summer under the Mediterranean climate. Mineral and organic acid content (by ion chromatography-IC), phenolic profile (by ultra-high performance liquid chromatography-UHPLC coupled with an Orbitrap high-resolution mass spectrometry-HRMS), carotenoid content (by high-performance liquid chromatography with diode array detection-HPLC-DAD), and antioxidant activities DPPH, ABTS, and FRAP (by UV-VIS spectrophotometry) were determined. Tomato fruits grown under the pearl grey net recorded the highest values of total phenolic compounds (14,997 µg 100 g−1 of fresh weight) and antioxidant activities DPPH, ABTS, and FRAP, without affecting either fruit color or marketable yield. The reduction of solar radiation through pearl grey nets proved to be an excellent tool to increase the phytochemical quality of tomato fruits during summer cultivation in a Mediterranean environment.

Salinity in water and soil is a critical issue for food production. Using biostimulants provides an effective strategy to protect crops from salinity-derived yield losses. The research supports the effectiveness of protein hydrolysate (PH) biostimulants based on their source material. A greenhouse experiment was performed on lettuce plants under control (0 mM NaCl) and high salinity conditions (30 mM NaCl) using the Trainer (T) and Vegamin (V) PH biostimulants. The recorded data included yield parameters, mineral contents, auxiliary pigments, and polyphenolics. The plant sample material was further analyzed to uncover the unique metabolomic trace of the two biostimulants. The results showed an increased yield (8.9/4.6%, T/V) and higher photosynthetic performance (14%) compared to control and salinity treatments. Increased yield in salinity condition by T compared to V was deemed significant due to the positive modulation in stress-protecting molecules having an oxidative stress relief effect such as lutein (39.9% 0 × T vs. 30 × V), β-carotene (23.4% vs. V overall), and flavonoids (27.7% vs. V). The effects of PH biostimulants on the physio-chemical and metabolic performance of lettuce plants are formulation dependent. However, they increased plant growth under stress conditions, which can prove profitable.

Protein hydrolysate biostimulants are environmentally friendly options for the reduction of nitrogen input, but their plant growth-promoting mechanisms are still not completely unveiled. Here, to put the “signaling peptide theory” to the test, a greenhouse experiment was undertaken using low (1 mM) and optimal (8 mM) NO3-treated butterhead lettuce and three molecular fractions (PH1 (>10 kDa), PH2 (1–10 kDa) and PH3 (

Over the years, the use of biostimulants has become increasingly widespread due to their proven efficiency in improving plant productivity and quality of fruits and mitigating the effects related to environmental stress. The aim of the present study was to evaluate the effect of three biostimulants on oil yield, production of drupes per plant, and nutraceutical components of olive drupes and oil (total polyphenols, anthocyanins, and fatty acids %) for “Racioppella” cultivar trees growing in South Italy (May–October 2021). The biostimulants used were: a tropical plants extract (A) containing amino acids, vitamins, enzymes, phytochelatins, macro- and microelements, a glycine betaine-based product (B), and a Trichoderma spp.-based biostimulant (T). The three biostimulants were compared with a control thesis (C) treated only with water. T treatment increased the polyphenols content of olive drupes by 41.04% compared to C. A and B treatments increased polyphenols content by 21.87% on average compared to C. All three biostimulants showed positive effect by increasing the amount of polyphenols in olive oil compared to C:T showed an increase of 32.19%, B 7.76%, and A 19.78%. Biostimulant application proved useful in boosting fundamental parameters that determine better drupe and oil in terms of antioxidant capacity and nutraceutical potential, other than an increased production.

Various products are used to mitigate the negative effects of abiotic stress in olive trees. The aim of the research was to examine an anti-transpirant product (Vapor Gard®, V) and a kaolin- based product (Manisol, K) effect on the growth of two-year-old olive tree seedlings under high temperature. The study was conducted in a greenhouse on trees of a native cultivar of Campania (cv. Salella) grown in pot during the growing season from May to September 2020. The experimental design included two products: di-1-p-menthene (product V) and kaolin (product K), applied five times at 20 day intervals compared with a control. The following biometric, physiological, and nutraceutical parameters were evaluated: stomatal conductance, chlorophyll a fluorescence, Soil Plant Analysis Development (SPAD) index, relative water content (RWC), shoots growth, total leaf area per plant, trunk cross-sectional area, dry matter partitioning, total polyphenols, and antioxidant activity. The results obtained showed that the application of di-1-p-menthene (V) was able to induce a significant improvement of shoots growth (+37.22%) and trunk cross-sectional area (+46.60%) and a reduction of the stomatal conductance and an increase of leaf RWC values. Application with kaolin had positive effects on the total polyphenol content, with an increase over the control of 240.33% and higher antioxidant activity values. Further studies are necessary to determine the effect of these products on the biometric, physiological and nutraceutical parameters of mature olive trees cultivated in open field conditions.

The goal of sustainable production is to reduce environmental degradation, to maintain agricultural productivity, to promote economic viability, as well as to reduce energy losses. Bedding plant sector is an important part of the nursery industry. Improving cultivation practices that increase the performance of potted ornamentals may become a promising and effectively sustainable strategy to be adopted in ornamental nursery. Among the important group of plant biostimulants soil activator complexes obtained by combination of macroalgae, zeolites, humic acids and soil bacteria improves the chemical-physical and microbiological properties of the substrate. The aim of this study was to assess the effect of a granular soil activator (Agrosil® Turf Algin) alone or in combination with two commercial controlled-release fertilizers (CRF) on growth, ornamental quality, leaf gas exchanges as well as mineral composition of two bedding plants: Begonia semperflorens and Salvia splendens. The plant growth parameters and the ornamental quality recorded in Agrosil-treated bedding plants were species-dependent, and were also affected by CRF type. Our results also demonstrated that the activator application enhanced several growth performance and quality parameters of the two selected bedding plants: plant height, canopy volume, leaf area and colorimetry, number of flowers in both species. The increased crop performance recorded in both species in the treatment B+A could be attributed to an increase in photosynthetic activity as well as to a better nutritional status (higher N, P, and K).

Promising strategies that could aid a shift from N-intensive agriculture to an eco-friendlier approach include the integrated use of plant-based biostimulants. To date, results about the accumulation of nitrate in green leafy vegetables due to biostimulant application are conflicting. Therefore, the current study aimed at assessing the effect of a new plant-based biostimulant, containing triacontanol (TRIA), that is claimed to reduce nitrate accumulation in leaves, based on the yield and leaf quality of lettuce grown in a plastic tunnel under different N conditions. The experimental design was a factorial combination of three nitrogen fertilization levels (N0, N30, and N60, corresponding to 0, 30, and 60 kg N ha−1) and two biostimulant applications (treated with ‘ILSASTIM+’ = YB and untreated control = NB). Nitrogen fertilization resulted in a 40% yield increase over N0. Biostimulant application increased the yield 21% over NB, and both improved all growth parameters. In addition, the biostimulant had a positive effect on color and Soil Plant Analysis development (SPAD) index, thus enhancing the qualitative aspect. Interestingly, biostimulant application boosted nitrogen use efficiency with a 23% increase over untreated plants. The use of biostimulant proved to be suitable to be applied in a sustainable strategy of production and quality improvement.

Increasing attention is being given to the development of innovative formulations to substitute the use of synthetic chemicals to improve agricultural production and resource use efficiency. Alternatives can include biological products containing beneficial microorganisms and bioactive metabolites able to inhibit plant pathogens, induce systemic resistance and promote plant growth. The efficacy of such bioformulations can be increased by the addition of polymers as adjuvants or carriers. Trichoderma afroharzianum T22, Azotobacter chroococcum 76A and 6-pentyl-α-pyrone (6PP, a Trichoderma secondary metabolite) were administrated singularly or in a consortium, with or without a carboxymethyl cellulose-based biopolymer (BP), and tested on sweet basil (Ocimum basilicum L.) grown in a protected greenhouse. The effect of the treatments on basil yield, photosynthetic activity and secondary metabolites production was assessed. Photosynthetic efficiency was augmented by the applications of the bioformulations. The applications to the rhizosphere with BP + 6PP and BP + T22 + 76A increased the total fresh weight of basil by 26.3% and 23.6%, respectively. Untargeted LC-MS qTOF analysis demonstrated that the plant metabolome was significantly modified by the treatments. Quantification of the profiles for the major phenolic acids indicated that the treatment with the T22 + 76A consortium increased rosmarinic acid content by 110%. The use of innovative bioformulations containing microbes, their metabolites and a biopolymer was found to modulate the cultivation of fresh basil by improving yield and quality, thus providing the opportunity to develop farming systems with minimal impact on the environmental footprint from the agricultural production process.

Hydroponics growing systems often contain excessive nutrients (especially nitrates), which could lead to a quality loss in ready-to-eat leafy vegetables and posing a health risk to consumers, if managed inadequately. A floating raft system was adopted to assay the production and quality performance of lettuce (Lactuca sativa L. cv ‘Maravilla De Verano Canasta’) deprived of the nutrient solution by replacement with only water, three and six days before harvest. Yield and quality parameters, mineral composition, pigments, organic acids, amino acids profile, soluble proteins, and carbohydrate content were determined. Nutrient solution deprivation six days before harvest resulted in a significant reduction in leaf nitrate (−53.3%) concomitant with 13.8% of yield loss, while plants deprived of nutrient solution three days before harvest increased total phenols content (32.5%) and total ascorbic acid (102.1%), antioxidant activity (82.7%), anthocyanins (7.9%), sucrose (38.9%), starch (19.5%), and γ-aminobutyric acid (GABA, 28.2%), with a yield reduction of 4.7%, compared to the control. Our results suggest that nutrient solution deprivation three days before harvest is a successful strategy to reduce nitrate content and increase the nutritional quality of lettuce grown in floating raft systems with negligible impact on yield. These promising results warrant further investigation of the potential effect of nutrient solution deprivation on the quality attributes of other leafy vegetables cultivated in floating raft systems and in a “cascade” growing system.

Lettuce (Lactuca sativa L.) is a winter-spring leafy vegetable, but the high demand for fresh products available year-round requires off-season production. However, the warm climate of the Mediterranean areas can impair the summer production of lettuce, thus requiring the adoption of genotypes tolerant to high irradiance as well as useful agronomic strategies like shading net installations. The aim of our research was to assess the leaf morpho-physiological and anatomical changes, in addition to productive responses, of four lettuce cultivars (‘Ballerina’, ‘Maravilla De Verano Canasta’, ‘Opalix’, and ‘Integral’) grown under shading and non-shading conditions to unveil the adaptive mechanisms of this crop in response to sub-optimal microclimate (high irradiance and temperature) in a protected environment. Growth and yield parameters, leaf gas exchanges, chlorophyll fluorescence and morpho-anatomical leaf traits (i.e., leaf mass area, stomatal density and epidermal cell density) were determined. Under shading conditions, the fresh yields of the cultivars ‘Ballerina’, ‘Opalix’ (‘Oak leaf’) and ‘Integral’ (‘Romaine’) increased by 16.0%, 26.9% and 13.2% respectively, compared to non-shading conditions while both abaxial and adaxial stomatal density decreased. In contrast, ‘Canasta’ under non-shading conditions increased fresh yield, dry biomass and instantaneous water use efficiency by 9.6%, 18.0% and 15.7%, respectively, while reduced abaxial stomatal density by 30.4%, compared to shading conditions. Regardless of cultivar, the unshaded treatment increased the leaf mass area by 19.5%. Even though high light intensity and high temperature are critical limiting factors for summer lettuce cultivation in a protected environment, ‘Canasta’ showed the most effective adaptive mechanisms and had the best production performance under sub-optimal microclimatic conditions. However, greenhouse coverage with a white shading net (49% screening) proved to be a suitable agricultural practice that ensured an adequate microclimate for the off-season growth of more sensitive cultivars ‘Ballerina’, ‘Oak leaf’ and ‘Romaine’.

The management of mineral elements in agriculture is important for their nutritional role for plants and dietary value for humans, sparking interest in strategies that can increase mineral use efficiency and accumulation in plant food. In this work, we evaluated the effects of the isosmotic variations of the concentration on three macrocations (K, Ca, and Mg) in lettuce (Lactuca sativa L.). Our aim was to improve the nutritional components of this valuable dietary source of minerals. Using a full factorial design, we analyzed mineral utilization efficiency (UtE), leaf morphology, gas exchange parameters, phenolic profiles (through ultra-high performance liquid chromatography coupled to a quadrupole-time-of-flight (UHPLC-QTOF) mass spectrometry), and enzymatic activities in two phytochemically diverse butterhead lettuce varieties (red or green). Plants were fed in hydroponics with three nutrient solutions (NSs) with different ratios of K, Ca, and Mg. The variation of these minerals in the edible product was associated with alterations of the morphology and physiology of the leaves, and of the quality and functional properties of lettuce, with a trade-off between total accumulation and mineral UtE. Moreover, in non-limiting conditions of nutrient availability, significant mineral interactions were also present. The flexibility of the plant response to the different ratios of macrocations, and the observed large intraspecific variation, were adequate to provide mineral-specific phytochemical profiles to the edible product. Specifically, the full-red lettuce provided more interesting results in regard to the compositional and functional attributes of the leaves.