Consumers are increasingly seeking innovative, healthy foods rich in nutraceuticals, driving the search for new or underutilized leafy vegetables. Leaf celery (Apium graveolens L. var. secalinum Alef.), a promising candidate for new food sources, stands out from ribbed celery with its smaller size and enhanced aroma. It is gaining global interest due to its high concentration of bioactive compounds, but it is presently cultivated only on soil in restricted regions. Significant knowledge gaps still exist regarding optimal agronomic management for its hydroponic baby leaf production and post-harvest cold storage as a minimally processed product. The necessity of adopting hydroponic systems for ready-to-eat leafy salads requires specific studies on techniques and nutrient management for novel vegetables like leaf celery. This research, for the first time, investigates the feasibility of producing fresh-cut suitable leaf celery baby leaves using a hydroponic ebb-and-flow cultivation system. We studied the effects of two plant densities (615 and 947 plants m⁻²) and three nutrient solution concentrations (NS) (only water, half strength, and full strength) on leaf celery growth, yield, and postharvest quality over two growing seasons (S1: winter/spring and S2: spring/summer). The experiment included two mowings per season to test the plant's regrowth capability, with morphological, biochemical, and yield characteristics assessed after each. Leaves from the first mowing of each trial were tested via sensory analysis and evaluated for shelf-life following minimal processing and cold storage (21 days at 4 °C). This research provides essential, globally transferable data for sustainable Controlled Environment Agriculture (CEA) by quantifying the yield, nutritional stability, and post-harvest longevity of this novel crop across critical seasonal and resource management variables. Results showed higher total yields in S1 (5.25 kg m⁻²) compared to S2 (2.76 kg m⁻²) using the full-strength NS, with nutrient availability effects varying by season and density. The full-strength NS maximized total yield, while the half-strength NS achieved the highest NUE (35.6 g DW g−1 N in S1). Importantly, the baby leaves exhibited good vitamin and mineral content with consistent stability across growing seasons and mowings. Their sensory profile showed only minor differences between seasons, generally maintaining a good overall evaluation. Crucially, the leaves maintained a shelf-life exceeding 14 days across all tested treatments. Overall, leaf celery proved well-suited for hydroponic cultivation, yielding baby leaves with excellent shelf-life and nutritional quality, offering a viable high-value option for the fresh-cut market.

The effect of a multi-species (Bacillus tequilensis, Peribacillus frigoritolerans, Pseudomonas lini, Pseudomonas frederiksbergensis, Pseudomonas atacamensis, Pseudomonas reinekei, and Pseudomonas granadensis) plant growth-promoting bacterial (PGPB) biostimulant on soil microbial dynamics and winter melon performance was evaluated over two growing seasons. In both trials PGPB were inoculated twice: at transplant and 30 days after transplant. Shortly after the first inoculation, total mesophilic bacteria increased by up to +1.8 log CFU g⁻¹ and total mesophilic anaerobic bacteria by +1.6 log CFU g⁻¹, while fungi rose from 4.35 to 5.15 log CFU g⁻¹ (p < 0.01). The second inoculation further enhanced bacterial abundance (+1.0 and +0.8 log units for TMB and TMaB, respectively), whereas fungal populations remained unchanged. By the end of the crop cycle, microbial counts converged between treatments. Culture-dependent tracking showed persistence of three out of the eight inoculated strains, with B. tequilensis and P. reinekei detected at harvest. Illumina profiling revealed strong early shifts in community structure, including an increase of Pseudomonas to 13.2 % and Bacillus to 13.8 %, followed by partial re-equilibration. Agronomically, inoculated plants exhibited enhanced vegetative growth (stem length +21.9 % at 20 days after transplant), earlier female flowering and accelerated fruit set. Total yield increased by 12.0 %, with early yield rising by 27.9 %, driven by a 37.6 % higher fruit number. Fruit quality also improved, showing a 15 % increase in firmness and higher soluble solid content (13.7 °Brix). These findings confirm that early microbial priming with this mixed inoculum drives lasting agronomic benefits, supporting efficient and sustainable winter melon production under field conditions.

In the context of increasing demand for sustainable floriculture, this study evaluated the effects of salicylic acid (SA) on phenotypic traits of poinsettia (Euphorbia pulcherrima Willd.). A factorial experiment was conducted in a commercial glasshouse using rooted poinsettia cuttings treated with three SA concentrations (10−3, 10−4, 10−5 M) applied via foliar or root application. Morphological parameters, colorimetric traits (CIELAB), canopy development, and biomass accumulation were assessed throughout the cultivation cycle. SA had no significant influence on the plant height, leaf number, or biomass of stems, leaves, and roots. However, notable phenotypic changes were observed. Foliar applications, particularly at 10−5 M, induced visible changes in leaf and bract color, including reduced brightness, saturation, and red pigmentation, especially in newly developed tissues. Conversely, root applications had milder effects and were generally associated with a more stable bract color. The 10−4 M root treatment promoted greater bract surface and color saturation. Canopy expansion and dry matter accumulation were also influenced by SA in a dose- and method-dependent manner, with high-dose foliar treatments (10−3 M) exerting suppressive effects. These findings suggest that the application mode and concentration of SA are critical in modulating ornamental quality traits, with low-to-moderate doses—particularly via root application—offering promising strategies to enhance plant performance in sustainable poinsettia cultivation.

Tetragonia tetragonioides, or New Zealand spinach, is a widespread halophyte native to eastern Asia, Australia, and New Zealand, and naturalized in some Mediterranean regions. This underutilized vegetable is consumed for its leaves, raw or cooked. For the first time, we investigated the feasibility of using whole baby plants (including stems and leaves) as raw material for ready-to-eat (RTE) vegetable production. Our study assessed Tetragonia’s suitability for hydroponic cultivation over two cycles (autumn–winter and spring). We investigated the impact of increasing nutrient rates (only water, half-strength, and full-strength nutrient solutions) and plant densities (365, 497, and 615 plants m−2 in the first trial and 615 and 947 plants m−2 in the second) on baby plant production. We also analyzed the plants’ morphological and biochemical characteristics, and their viability for cold storage (21 days at 4 °C) as a minimally processed product. Tetragonia adapted well to hydroponic cultivation across both growing periods. Nevertheless, climatic conditions, plant density, and nutrient supply significantly influenced plant growth, yield, nutritional quality, and post-harvest storage. The highest plant density combined with the full-strength nutrient solution resulted in the highest yield, especially during spring (1.8 kg m−2), and favorable nutritional characteristics (β-carotene, Vitamin C, Fe, Cu, Mn, and Zn). Furthermore, Tetragonia baby plants proved suitable for minimal processing, maintaining good quality retention for a minimum of 14 days, thus resulting in a viable option for the RTE vegetable market.

Tomato is one of the most important crops worldwide, with a production of ≈190 million tons, but it is constantly threatened by several viral diseases. Tomato brown rugose fruit virus (ToBRFV), identified in 2014 on tomato plants and subsequently reported in many countries, represents one of the major threats to tomato crops, due to production losses, different transmission modes and its rapid spread. This work aimed to evaluate 37 local Sicilian tomato ecotypes against ToBRFV infection. After a preliminary screening by molecular analyses for tomato mosaic virus (ToMV) and pepino mosaic virus (PepMV), and ToBRFV detection, tomato plants were grown in a greenhouse for their morphological characterization and for evaluating resistance and tolerance to ToBRFV. Resistance and tolerance levels were estimated by mechanical inoculation with ToB SIC01/19 ToBRFV isolate in ten plants per ecotype and evaluating virus accumulation by RT-qPCR and visual observation of symptoms. All ecotypes were infected with ToBRFV, showing several symptoms with different disease severity. No tomato ecotype showed a high level of resistance, but two ecotypes, Pop27 and Pop35, showed very moderate symptoms and therefore a high tolerance. These Sicilian tomato ecotypes could be used in genetic breeding programs as parental ones to obtain cultivars tolerant to ToBRFV.

Golden tomato (GT), harvested at the veraison stage, has gained attention due to its rich content of bioactive compounds and potential health benefits. Previous studies have highlighted GT’s antioxidant properties and its positive effects on metabolic syndrome (MetS), a condition characterized by obesity, dyslipidemia, and oxidative stress. This study investigates for the first time a derivative from GT, i.e., the juice (GTJ), which could be a potential candidate for development as a functional food. We first characterized GT juice, identifying 9-oxo-10(E),12(E)-octadecadienoic (9-oxo-10(E),12(E)-ODA) fatty acid, a known peroxisome proliferator-activated receptor alpha (PPAR-α) agonist, using High-Performance Liquid Chromatography (HPLC)–mass spectrometry. Then, using a high-fat-diet (HFD) rat model, we assessed the impact of daily GT juice supplementation in addressing MetS. We outlined that GTJ improved body weight and leptin-mediated food intake. Moreover, it ameliorated glucose tolerance, lipid profile, systemic redox homeostasis, hepatic oxidative stress, and steatosis in HFD rats. Furthermore, GT juice enhances the hepatic transcription of PPAR-α, thus putatively promoting fatty acid oxidation and lipid metabolism. These findings suggest that GT juice mitigates lipidic accumulation and putatively halters oxidative species at the hepatic level through PPAR-α activation. Our study underscores the protective effects of GT juice against MetS, highlighting its future potential as a nutraceutical for improving dysmetabolism and associated alterations.

Clinical embryologists are highly trained laboratory professionals with multiple roles, including laboratory, clinical, biobanking and quality system management. In most European countries, clinical embryologists are trained to work in Medically Assisted Reproduction (MAR) centres without a specifically dedicated educational path. The criteria required for employment vary according to the educational structure and the public or private nature of the centre. We have herein described the educational profile required by Italian clinical embryologists to work in MAR centres of the National Health System (NHS). Public centres currently represent 36% of all the Italian MAR clinics. According to the Italian law, a future clinical embryologist must achieve a 3-4 year unpaid post-graduate specialization in a different field, choosing from Genetics, Microbiology, Clinical Pathology or Nutrition. Accesses to the above-mentioned post-graduate courses are themselves very limited. Clinical embryologists are basically trained by senior colleagues. This situation makes inevitably difficult to recruit laboratory staff in NHS centres. Moreover, it represents an emblematic example of the need for an equal training curriculum, possibly ensuring a comparable education quality, mobility of trainees and dissemination of skills for clinical embryologists all over Europe.

A correct cultivation technique supported by scientific evidence that leads to high-quality standards can promote sustainable floriculture. It is urgent to find alternative solutions to the widely used chemical fertilizers and evaluate the effectiveness of other fertilizers. The liquid organic ones, already in use in organic vegetable farming, could be a good substitute if supplied together with growth-promoting products such as microbial biostimulants. In the hope of replacing the traditional chemicals with a more sustainable organic-based fertilization, the present investigation aimed to evaluate the effects of a microbial biostimulant and various combinations of organic and mineral fertilization on morphological characteristics and physiological parameters of Tagetes patula L. and Ageratum houstonianum Mill. The plants were grown in pots with a substrate inoculated or not with the microbial biostimulant and were fertigated with nutrient solutions at different concentrations of elements from mineral and/or organic sources. Six fertilization formulas were adopted: control (only water without fertilizer), 100% mineral fertilization, 50% mineral fertilization, 100% organic fertilization, 50% organic fertilization, and 50% mineral + 50% organic fertilization. For the organic fertilization, a commercial liquid fertilizer admitted in organic farming with 3-2-5.5 NPK with 3% organic nitrogen was used. Mineral fertilization was formulated to match the organic solution as closely as possible. We observed an improvement in ornamental value (stem diameter and shoot number) with the biostimulant inoculum. Generally, the 50% mineral and 50% organic fertilization did not negatively influence the morphological characteristics. The reduction by 50% in the mineral nutrients and the integration of this reduction with an organic fertilizer was feasible to produce potted plants of these species during spring in the Mediterranean area.

The shortage of good quantity and quality of water for irrigated agriculture is a major problem in arid and semiarid regions. To deal with this problem, deficit irrigation (DI) or arbuscular mycorrhizal fungi (AMF) inoculation have been proposed and adopted for many crops as a tool to save water, or to improve crop tolerance to drought stress. An experiment was conducted for two consecutive years to evaluate the effect of mycorrhizal inoculation on the physiological, morphological, yield, and quality characteristics of melon plants grown under deficit irrigation. Melon crop (Cucumis melo L. cv. Helios) was grown under field conditions adopting a split-plot design with four replications, where DI was the main factor and AMF inoculation was the secondary factor. DI treatments consisted of applying 60%, 80%, or 100% of crop evapotranspiration (ETc) on melon plants inoculated or not with a commercial biostimulant containing 50% of Rhizophagus irregularis, and 50% of Funneliformis mosseae. Moderate and severe deficit irrigation significantly reduced the relative water content, stomatal conductance, yield, nitrogen applied efficiency (NAE), and fruit firmness of the uninoculated plants, but significantly increased irrigation water use efficiency (IWUE) and the ascorbic acid content of the fruit. AMF had a positive effect on plant tolerance to moderate water stress, and on some fruit quality parameters (fruit length, firmness, and sugar content). The combined use of moderate deficit irrigation (80%) and soil inoculation with AMF on melon plants allows water savings without affecting fruit yield, and increases IWUE, NAE, and some fruit quality characteristics (firmness, SSC, and SSC/TA). Furthermore, the use of AMF plants could be worth it to reduce the yield loss and increase fruit quality, even with severe deficit irrigation (60%).

The agricultural practices applied in pre-harvest greatly influence the presence and the levels of microorganisms in fresh produce. Among these, Listeria monocytogenes represents one of the most lethal foodborne pathogens associated with vegetables. The main hypothesis of this work is that bacteriocin producer Enterococcus mundtii strains can be effective against L. monocytogenes in soil. To this purpose, bacteriocin production by E. mundtii WFE3, WFE20 and WFE31, three strains showing a strong bacteriocin activity in terms of inhibitory power and inhibition spectra, was evaluated in sterile extracts from agricultural soil and peat moss, in organic nutrient solution (ONS) and mineral nutrient solution (MNS). ONS supernatants from E. mundtii WFE3 showed the highest inhibition of the strain L. monocytogenes ATCC 19114. Thus, this strain [104 colony forming units (CFU) g(-1) dw] was co-inoculated with E. mundtii WFE3 (106 CFU g(-1) dw) in the sterile extracts and solutions. A general increase of E. mundtii cell densities and the contemporary decrease of the levels of L. monocytogenes were observed, particularly in ONS. This solution was used to amend autoclaved soil to test in vivo the competition among bacteriocin producer and sensitive strain. L. monocytogenes decreased of almost 1.5 log CFU when E. mundtii was added to soil. The test was also carried out with basil plants showing that the anti-Listeria effect of E. mundtii is exerted during the very first days from inoculation. After 2 days, the levels of NO3--N in soil increased for all trials, while the concentrations of ammonium and alpha-amino N decreased. The lowest concentrations of NH4+-N were found in presence of L. monocytogenes. At harvest, the plants were analysed for the presence of E. mundtii and L. monocytogenes, but none of the two bacterial species deliberately added to soil was transferred to plants. Although a biocontrol based on bacteriocin application in soil has to be properly set, this study provides useful insight for the future development of chemical-free agricultural strategies.

Ecklonia maxima and the commercial biostimulants produced from it contain various plant growth regulators that are responsible for the growth stimulation recorded in many crops. Auxins are one of the major plant growth regulators contained in E. maxima extracts. The aim of this research was to evaluate the growth-promoting effect of a seaweed extract from E. maxima on lettuce and tomato transplant production under nursery conditions, and to compare the effect of this extract with an equal concentration of synthetic auxin. Two doses of natural or synthetic exogenous auxins (50 or 100 μg L−1) were supplied to the substrate through the irrigation water with an ebb and flow system, 4, 11, and 18 days after sowing. A commercial biostimulant based on E. maxima extract was used as a source of natural auxin, while 1-naphthaleneacetic acid (NAA) was used as a synthetic auxin. Seedlings supplied only with water were used as a control. Tomato seedlings treated with 100 μg L−1 of natural auxins from E. maxima extract produced the tallest plants (+22%), with a higher leaf number (+12%), a wider leaf area (+44%), and a stronger stem (+12%), whereas lettuce seedling growth was promoted by all the treatments, but with a greater effect with increasing auxin supplementation and when using E. maxima extract, compared to NAA. The results showed that the supplementation of exogenous synthetic auxin (NAA), or an E. maxima extract containing natural auxins, can have a growth-promoting effect on lettuce and tomato seedlings. This effect was more evident on lettuce than tomato. The biostimulant produced from E. maxima extracts improved seedling quality and promoted shoot and root growth more than the NAA used as a synthetic source of auxins.

A commercial biodegradable starch-based polymer (Mater-Bi) was activated with carvacrol to develop a biodegradable and compostable polymer to be used in food packaging. Based on previous tests, carvacrol was added at 20 % weight of foam. MB foams, with and without carvacrol, were tested for their morphological characteristics, mechanical tests and kinetics of carvacrol release under refrigerated storage conditions. Carvacrol slightly increased the porosity of the foams, induced a reduction of the compressive elastic modulus (E-com) of foamed MB from 6 to similar to 3.4 MPa and a decrease of the tensile elastic modulus from similar to 70 MPa to similar to 16.5 MPa. Carvacrol release from the foam at 4 degrees C was almost 7% of the initially loaded amount at the fifth hour, while 35.4 % at the end of the test (900 h). MB containing carvacrol was active against several pathogenic and spoilage bacteria in vitro. Trays made of MB containing carvacrol were put in contact with meat, fish and vegetable food systems, artificially contaminated with Pseudomonas poae 4G558 and Listeria monocytogenes 13BO. No antimicrobial effect of MB foams was registered for ham and salmon trials, while a clear inhibitory effect of carvacrol activated MB foams was observed for contaminated melon and pumpkin in which both bacteria decreased of about 1 log cycle after 3 d and completely disappeared from the 7th d of refrigerated storage. This study provided evidences on the suitability of MB foams containing 20 % carvacrol as active packaging systems for vegetables even though it negatively affected their physicochemical parameters and overall quality.

The research aimed to evaluate the use of synthetic or natural auxins on the growth of tomato seedlings. The seeds of Solanum lycopersicum Marmande were sown in polystyrene plug plant trays (104 cells). Two doses of natural or synthetic exogenous auxins (200 ppm and 100 ppm) were supplied to the substrate through the irrigation water with an ebb and flow system 3, 11, and 17 days after sowing (05, 11, and 13th BBCH growth stage, respectively). A commercial biostimulant based on Ecklonia maxima extracts (Basfoliar® Kelp SL Compo) was used as a source of natural auxin while 1-naphthaleneacetic acid NAA was used as a synthetic auxin. Seedlings supplied only with water were used as a control. The treatments had significant effects on many morphological and physiological parameters (plant height, stem diameter, plant fresh and dry weight, leaf number and area, stomatal conductance, plant water use, and water use efficiency). Seedlings treated with both doses of exogenous auxin provided via Ecklonia maxima extracts increased their fresh and dry weight by 31% and 37% respectively and were taller and leafier than the control seedlings. The use of NAA had a negative effect on plant height and stem fresh and dry weight but did not alter the other morpho-physiological parameters as compared to the control seedlings. The treatments with auxins from algae extract during nursery growth improved the performance of tomato seedlings but the benefits could be probably ascribed not only to auxins themselves but to the synergic effect of the other organic compounds contained in the product (amino acids, proteins, carbohydrates, and vitamins).

Vegetable plants are more sensitive to salt stress during the early growth stages, hence, the availability of poor-quality brackish water can be a big issue for the nursery vegetable industry. Microbial biostimulants may promote growth and vigor and counterbalance salt stress in mature plants. This study aimed to evaluate the application of plant growth-promoting microorganisms for improving salt tolerance of tomato seedlings irrigated with increasing salinity (0, 25, and 50 mM NaCl) during nursery growth. Two commercial microbial biostimulants were applied to the substrate before seeding: 1.5 g L-1 of TNC BactorrS13 containing 1.3 x 108 CFU g-1 of Bacillus spp.; 0.15 g L-1 of Flortis Micorrize containing 30 % of Glomus spp., 1.24 x 108 CFU g-1 of Agrobacterium radobacter, Bacillus subtilis, Streptomyces spp. and 3 x 105 CFU g-1 of Thricoderma spp.. Tomato seedlings suffered negative effects of salinity on plant height, biomass, shoot/root ratio, leaf number, leaf area, relative water content, and stomatal conductance. The use of the bacterial biostimulants modified seedling growth and its response to salt stress. They had a growth-promoting effect on the unstressed tomato seedlings increasing fresh and dry biomass accumulation, leaf number, and leaf area and were successful in increasing salinity tolerance of tomato seedlings especially when using Flortis Micorizze that enhanced salinity tolerance up to 50 mM NaCl. The inoculation of the substrate with microbial biostimulants could represent a sustainable way to improve tomato transplant quality and to use brackish water in vegetable nurseries limiting its negative effect on seedling growth.

Vegetable plants are more sensitive to salt stress during the early growth stages; hence, the availability of poor-quality brackish water can be a big issue for the nursery vegetable industry. Microbial biostimulants promote growth and vigor and counterbalance salt stress in mature plants. This study aimed to evaluate the application of plant growth-promoting microorganisms for improving salt tolerance of lettuce and tomato seedlings irrigated with different water salinity levels (0, 25, and 50 mM NaCl) during nursery growth. Two commercial microbial biostimulants were applied to the substrate before seeding: 1.5 g L−1 of TNC BactorrS13 containing 1.3 × 108 CFU g−1 of Bacillus spp.; 0.75 g L−1 of Flortis Micorrize containing 30% of Glomus spp., 1.24 × 108 CFU g−1 of Agrobacterium radiobacter, Bacillus subtilis, Streptomyces spp. and 3 × 105 CFU g−1 of Thricoderma spp. Many morpho-physiological parameters of lettuce and tomato seedlings suffered the negative effect of salinity. The use of the microbial biostimulants modified seedling growth and its response to salt stress. They had a growth-promoting effect on the unstressed seedlings increasing fresh and dry biomass accumulation, leaf number, and leaf area and were successful in increasing salinity tolerance of seedlings especially when using Flortis Micorizze that enhanced salinity tolerance up to 50 mM NaCl. The inoculation of the substrate with microbial biostimulants could represent a sustainable way to improve lettuce and tomato transplant quality and to use brackish water in vegetable nurseries limiting its negative effect on seedling growth.

Strawberry fruit is a nonclimacteric fruit and is one of the most consumed berries in the world. It is characterized by high levels of vitamin C, folate, vitamin E, β-carotene, and phenolic constituents as well asanthocyanins that are strictly related to health benefits. Strawberries are highly perishable fruit with a very short postharvest life due to their susceptibility to mechanical injury, rapid texture softening, physiological disorders, and infection caused by several pathogens (yeast and mold) that can rapidly reduce fruit quality. The aim of the present study was to evaluate the effect of the application of Opuntia ficus-indica mucilage in combination with ascorbic acid, as edible coating, on quality, sensorial parameters, and microbiological characteristics of strawberry fruit during cold storage at 4 ± 0.5°C and 85% RH. Strawberries were characterized by a linear increase of weight loss during the storage at 4°C that was significantly higher (+11.3% on average) in the uncoated strawberries. The coating affected the ascorbic acid content of the strawberries that increased by 36.0% in coated strawberries; total soluble solid content and color of the strawberries were only affected by storage. Visual quality and sensorial analysis recorded higher scores in the coated samples at the end of the cold storage period. Furthermore, the mucilage coating did not negatively affect the natural taste of strawberries. The application of O. ficus-indica gel-based edible coating in combination with ascorbic acid, although not able to inhibit the microbial growth, limited significantly their development in coated strawberry fruits. Our results suggest that Opuntia mucilage plus 5% ascorbic acid could be a useful biochemical way of maintaining strawberry fruit quality and extending their postharvest life.

Today there is a greater environmental and ecological awareness and it is growing the number of farmers who want to adopt sustainable and efficient cultivation systems even if not officially certified as organic. Sustainable and modern cultivation systems must involve organic fertilization and cannot ignore the role of rhizosphere microorganisms. Starting from this premise, this paper aimed to evaluate the use of plant growth-promoting rhizobacteria (PGPR) and organic liquid fertilizers on soilless cultivation of basil. Genovese basil plants were cultivated in pots filled with a substrate inoculated or not with a commercial biostimulant (TNC BactorrS13) containing growth-promoting rhizobacteria (Bacillus spp.). Plants were fed only with water (control without fertilization) or with nutrient solutions (NS) that provided the same amount of nutrients with five combinations of mineral (M) and organic (O) fertilizers: 100 % M, 75 % M + 25 % O, 50 % M + 50 % O, 25 % M + 75 % O, 100 % O. The inoculum of the substrate with PGPR had no significant effect on basil plant growth but showed to be effective in decreasing the nitrate content of basil leaves. Several plant characteristics (e.g. yield, fresh and dry biomass, leaf number and area, stem diameter, etc.) showed to be negatively affected by the progressive reduction of the percentage of mineral fertilizer in the nutrient solution, in favor of the organic one, which, on the other hand, determined a significant reduction of the nitrate content of basil leaves.

Ecklonia maxima is a brown algae seaweed largely harvested over the last years and used to produce alginate, animal feed, fertilizers, and plant biostimulants. Their extracts are commercially available in various forms and have been applied to many crops for their growth-promoting effects which may vary according to the treated species and doses applied. The aim of the study was to characterize the effect of adding an Ecklonia maxima commercial extract (Basfoliar Kelp; 0, 1, 2, and 4 mL L−1) to the nutrient solution of a hydroponic floating system on growth, yield, and quality of leaf lettuce at harvest and during cold storage (21 days at 4 °C). The supplementation of the E. maxima extract through the mineral nutrient solutions, especially between 2 and 4 mL L−1, enhanced plant growth and improved the yield and many morphological and physiological traits (biomass accumulation, leaf expansion, stomatal conductance, water use efficiency, nitrogen use efficiency, etc.). Preharvest treatments with E. maxima extract were effective in delaying leaf senescence and extending the shelf-life of fresh-cut leaf lettuce. The delay in leaf decay of treated samples allowed to retain an overall quality over the threshold of marketability for up to 21 d of cold storage, especially using 2 mL L−1 of extract.

Plant growth-promoting rhizobacteria have been applied to different vegetable crops but there is still no information on the effect of bacterial biostimulant application under variable nutritional level on lettuce seedlings and their performance after transplanting in the field. This study aimed to evaluate the efficacy of a bacterial biostimulant to enhance growth and quality of lettuce seedlings fertigated with increasing nutrient rates and to assess the efficacy of these treatments on lettuce head production. Lettuce seedlings were inoculated with 1.5 g L−1 of TNC BactorrS13 (a commercial biostimulant containing 1.3 × 108 CFU g−1 of Bacillus spp.) and fertigated with a nutrient solution containing 0, 1, 2, and 4 g L−1 of NPK fertilizer (20-20-20). At the end of transplant production, the plants were evaluated for greenhouse cultivation. The effect of fertigation rate on seedling height, dry biomass, dry matter percentage, and water use efficiency was evident up to 2 g L−1 of fertilizer in the non-inoculated seedlings, whereas fresh biomass and nitrogen use efficiency changed up to 4 g L−1 of fertilizer. The use of the bacterial biostimulant modified seedling growth and its response to nutrient availability. The inoculation of the substrate with Bacillus spp. promoted plant growth and allowed seedlings to reach the highest height and biomass accumulation. The physiological age of lettuce seedlings showed a strong influence on plant growth and production after transplanting. The bacterial treatment positively affected the yield and nitrate content of lettuce plants.

Mediterranean areas with intensive agriculture are characterized by high salinity of groundwater. The use of this water in hydroponic cultivations can lead to nutrient solutions with an electrical conductivity that overcomes the tolerance threshold of many vegetable species. Plant growth-promoting rhizobacteria (PGPR) were shown to minimize salt stress on several vegetable crops but the studies on the application of PGPR on leafy vegetables grown in hydroponics are rather limited and have not been used under salt stress conditions. This study aimed to evaluate the use of plant growth-promoting bacteria to increase the salt tolerance of leaf lettuce grown in autumn and spring in a floating system, by adding a bacterial biostimulant (1.5 g L−1 of TNC BactorrS13 a commercial biostimulant containing 1.3 × 108 CFU g−1 of Bacillus spp.) to mineral nutrient solutions (MNS) with two salinity levels (0 and 20 mM NaCl). Leaf lettuce plants showed a significant reduction of growth and yield under salt stress, determined by the reduction of biomass, leaf number, and leaf area. Plants showed to be more tolerant to salinity in autumn than in spring. The inhibition of lettuce plant growth due to salt stress was significantly alleviated by the addition of the bacterial biostimulant to the MNS, which had a positive effect on plant growth and fresh and dry biomass accumulation of the unstressed lettuce in both cultivation seasons, and maintained this positive effect in brackish MNS, with similar or even significantly higher values of morphologic, physiologic, and yield parameters than those recorded in control unstressed plants.