Growth Of Lettuce Research Articles

Effects of far-red light on growth, endogenous hormones, antioxidant capacity and quality of Lettuce

This study aimed to explore the effects of various intensities of far-red light on the growth performance, endogenous hormones, antioxidant indices, and overall quality of hydroponically cultivated lettuce. As the control treatment, a white LED emitting light at an intensity of 200 µmol/(m2·s) was utilized (referred to as CK with an R/FR ratio of 5.5), while two experimental treatments, FT1 (R/FR = 1.2) and FT2 (R/FR = 0.8), were established by adding different intensities of far-red light to the CK treatment. The results demonstrated that the application of far-red light, particularly in FT1, led to a significant increase in plant height, leaf area, and lettuce biomass, while simultaneously resulting in a notable reduction in leaf thickness. The content of indole-3-acetic acid (IAA) and abscisic acid (ABA) in response to far-red light treatments exhibited an initial increase followed by a subsequent decrease, with FT2 experiencing a significant decline. The gibberellin (GA3) content in FT2 reached its peak on the 35th day, showing a substantial increase of 60.09% compared to CK. Far-red treatments were found to enhance peroxidase (POD) and catalase (CAT) activities, while significantly reducing superoxide dismutase (SOD) activity. In comparison to CK, FT1 exhibited a remarkable 134.33% increase in anthocyanin content. Both FT1 and FT2 significantly boosted vitamin C levels while reducing nitrite content. Additionally, the application of far-red light treatment significantly increased the alcohol and ester content in lettuce leaves. This study establishes a theoretical foundation for enhancing the quality and flavor of lettuce using different far-red light treatments.Graphical

Light manipulation as a route to enhancement of antioxidant properties in red amaranth and red lettuce.

With the growing global population and climate change, achieving food security is a pressing challenge. Vertical farming has the potential to support local food production and security. As a Total Controlled Environment Agriculture (TCEA) system, vertical farming employs LED lighting which offers opportunities to modulate light spectrum and intensity, and thus can be used to influence plant growth and phytochemical composition, including antioxidants beneficial for human health. In this study, we investigated the effect of four red-to-blue light ratios of LEDs (R:B 1, 2.5, 5 and 9) on the growth and antioxidant components in red amaranth microgreens and red lettuce. Plant growth, total phenols, betalains, anthocyanins, vitamin C and antioxidant capacity (ferric reducing antioxidant power assay) were evaluated. A higher proportion of red light resulted in biometric responses, i.e., stem elongation in red amaranth and longer leaves in red lettuce, while the increase in the blue light fraction led to the upregulation of antioxidative components, especially total phenols, betalains (in red amaranth) and anthocyanins (in red lettuce). The antioxidant capacity of both crops was strongly positively correlated with the levels of these phytochemicals. Optimizing the red-to-blue ratio in LED lighting could be effective in promoting antioxidant-rich crops with potential health benefits for consumers.

Quantification and polymeric characterization of microplastics in composts and their accumulation in lettuce

Organic fertilizers have become a vector for the transport of microplastics (MPs), which pose human health concerns through the food chain. This study aimed to quantify and characterize MPs in eight different compost samples of various raw materials and their subsequent translocation to lettuce (Lacuta sativa) grown on contaminated composts. The results revealed that the MP abundance ranged from 3810 to 16530 MP/kg. Municipal solid waste compost (MSWC) had highest abundance (16082 ± 632 MP/kg), followed by leaf compost (LC) and organic compost (OC) (6299 ± 1011 and 3680 ± 419 MP/kg, respectively). MPs of <100 μm in size were most dominant in MSWC and LC. Fragments and fibers were the prevalent shape types, with white/transparent colored MPs being more abundant. Polyethylene (PE), polypropylene (PP) and polyethylene terephthalate (PET) were the dominant polymers. MPs accumulation in the lettuce leaves was greatest in the lettuce plants grown on MSWC, followed by those grown on LC and OC, indicating that MSWC grown lettuce is not suitable for human consumption. The decrease in the growth (leaf length, number of leaves, leaf fresh and weights) and physiological (membrane stability index, relative water contents) parameters of lettuce was in line with the trend of MP accumulations. Hence, it is highly important to regulate the plastic contents in compost because it is a threat to ecosystems and human health.

Growth and Yield of Lettuce (Lactuca sativa var. crispa) in Varying Irrigation Water Salinity and Leaching Fractions

This study aimed to determine the response of yield and yield parameters of the ‘Cospirina’ lettuce plant, known to be moderate salinity tolerant, to different levels of salt water applications and different leaching rates in the Eastern Mediterranean Region of Hatay Province, Türkiye. Lettuce was irrigated at three different irrigation water salinity levels (EC0 = 0.5 dS m-1-control, EC2 = 2 dS m-1, EC4 = 4 dS m-1) and four different leaching fractions (LF0 = 0%, LF1 = 10%, LF2 = 20%, LF3 = 30%). Irrigation water salinity was adjusted by adding different amounts of NaCl salt to the tap water (EC0, control) with an EC value of 0.5 dS m-1. Plant water consumption (PWC) increased as the leaching fraction increased but decreased as salinity increased. PWC ranged from 7.32 – 10.5 L for EC0, 7.0 – 8.46 L for EC2, and 5.0 – 6.46 L for EC4. The mean water use efficiency (WUEy) was calculated as 31.43 g L-1, 32.12 g L-1, and 34.77 g L-1 in EC0, EC2, and EC4, respectively. Lettuce yield decreased with increasing soil salinity and the leaching fraction. Yield ranged from 182 g plant-1 (EC4LF0) to 282 g plant-1 (EC0LF2). When soil salinity increased from 0.82 dS m-1 (EC0) to 1.31 dS m-1 (EC2) and 2.09 dS m-1 (EC4), yields decreased by 10% and 28%, respectively. Increasing salinity significantly decreased the root length, root width, leaf number, number of commercial leaves, leaf width, leaf length, and biomass, while commercial head length and commercial head diameter remained unaffected.

Produção de alface crespa utilizando água residuária da mandioca como fonte de potássio

ABSTRACT Cassava wastewater (CWW) is a natural biofertilizer successfully tested as a source of K in long-cycle crops; however, it still needs to be better evaluated in short-cycle crops. This study aimed to evaluate the use of CWW as a source of K in the growth, yield, and physicochemical quality of curly lettuce. The study was conducted in a greenhouse, in a randomized block design arranged in a 5 × 2 + 1 factorial scheme, with four replicates. Five CWW doses were evaluated as an exclusive source of K: 0, 60, 120, 180, and 240 kg ha-1 of K2O; two forms of application: 1-total dose at planting: 2-application of 50% of the dose at planting + 50% of the dose in topdressing, and an additional treatment: 100% mineral fertilization at 120 kg ha-1 of K2O dose, using KCl as the source. The number of leaves (NL), plant height (PH), fresh mass (FM), dry mass (DM), moisture (MO), ashes (ASH), fibers (FB), lipids (LIP), proteins (PTN), and carbohydrates (CHO) contents were evaluated. All agronomic attributes of lettuce showed lower values when fertilized only with CWW than mineral fertilization. Lettuce fertilized only with CWW, depending on total or split application and dose, showed higher ASH, FB, LIP, PTN, and CHO contents reaching 4.05, 3.97, 1.75, 7.11, and 3.63%, respectively, compared to mineral fertilization. The CWW can potentially be used as a complementary K source in lettuce cultivation, as its exclusive use does not replace traditional mineral fertilization.

The Impact of Biochar and Compost as Soil Amendments, Combined with Poultry Manure, on the Growth, Yield, and Chemical Composition of Lettuce (&lt;i&gt;Lactuca sativa&lt;/i&gt;)

The Impact of Biochar and Compost as Soil Amendments, Combined with Poultry Manure, on the Growth, Yield, and Chemical Composition of Lettuce (&lt;i&gt;Lactuca sativa&lt;/i&gt;)

Thermotolerant plant growth-promoting bacteria enhance growth and nutrient uptake of lettuce under heat stress conditions by altering stomatal movement and chlorophyll fluorescence.

The online version contains supplementary material available at 10.1007/s12298-024-01470-5.

Strategy to Increase Lettuce Plant Growth (Lactuca sativa L.) with fertilization optimization

Lettuce is a horticultural commodity that has quite good commercial value. This research was carried out on houseland in Pondok Batu Village, Bilah Hulu District, Labuhan Batu Regency from March 2024 to May 2024. This research aimed to see the effectiveness of NPK fertilizer application on the growth and production of lettuce (Lactuca sativa L). This research aims to determine the type of planting media and the correct dose of NPK fertilizer for optimum growth and yield of lettuce so that it can become information that can be used by the public. Data analysis showed that plants given NPK fertilizer had higher yields and better overall health than plants without fertilizer It is hoped that the use of NPK fertilizer will make it easier to apply in the field and can increase the required nutrient content in the soil and can be used directly by plants. This research used a Randomized Group Design (RAK) consisting of 4 treatments. P0 Soil planting media, P1 Soil planting media; dose of NPK fertilizer 100 grams, P2 Soil planting media; NPK fertilizer dose 200 grams, P3 Soil planting media; NPK fertilizer dose 300 grams

Far-red radiation management for lettuce growth: Physiological and morphological features leading to energy optimization in vertical farming

Recently, far-red wavelengths (FR, 700–750 nm) have been largely investigated in indoor cultivation systems due to their morphological effects on plants (e.g., leaf expansion and stem elongation), resulting also in increasing yield. This work investigated the effect of substituting part of the red (R) and blue (B) radiation with far-red radiation, while keeping constant the photon flux density, in the light spectrum for lettuce grown in a vertical farm. Lettuce (Lactuca sativa var. Canasta) plants were transplanted and grown in an ebb-and-flow system for 29 days. During the cycle, plants were subjected to five different light treatments: a control treatment consisting of an optimized R and B spectrum (ratio of 3; RB3) with a photosynthetic photon flux density of 200 µmol m−2 s−1, and four treatments in which R and B were partially replaced by 10, 30, 50 and 70 µmol m−2 s−1 of FR light, resulting in an increasing FR fraction. Biomass production and most of the morphological parameters were affected from 15 days after transplanting (DAT), while stomatal conductance from 22 DAT. Leaf greenness and specific leaf area values were influenced by the FR radiation starting from 8 DAT. At 29 DAT, substitution of an amount of R and B photons equal to 30 (RB3–30) or 50 (RB3–50) µmol m−2 s−1 with the same amount of FR radiation resulted in increased leaf biomass in both fresh (+49 and +47%, respectively) and dry weight (+45 and +42%, respectively). With RB3–30, the increase was due to leaf area expansion (+103%), whereas stomatal conductance (gs) and quantum efficiency of photosystem II (ΦPSII) did not change compared with the spectrum with only R and B. With RB3–50, gs and ΦPSII decreased compared with RB3 (-27 and -6%, respectively), but the greater biomass accumulation was supported by the greater leaf expansion (+119 %). The adoption of RB3–30 and RB3–50 also promoted light use efficiency (+45 and +42 %, respectively), lighting energy use efficiency (+48 and +53 %, respectively) and therefore the overall energy performance of the system. The adoption of RB3–30 and RB3–50 is a valid strategy to increase yield for lettuce production, but further studies, also in relation to blue radiation intensity, are needed to avoid the negative effect on leaf pigmentation.

Response Surface Methodology for Development of Nutrient Solution Formula for Hydroponic Lettuce Based on the Micro-Elements Fertilizer Requirements at Different Growth Stages

In order to precisely obtain the impact of nutritional elements on lettuce yield and quality, in the present study, a nutrient solution formula suitable for lettuce hydroponic production was development using response surface methodology based on the determination for micro-elements in three growth stages and taking the interaction between elements into account. Then, the formula was optimized and validated, aiming for the goal of improving lettuce yield and quality. The results showed that 200 healthy lettuce leaves contained similar amounts of macro-elements, and there was no significant difference in the unit content of micro-elements among the seedling, rosette, and harvest stages. Quadratic regression models between shoot fresh weight, SPAD value, soluble sugar content, Vc content, and nutrient content were established (R2 = 0.91, 0.95, 0.98, and 0.81, respectively). The optimal concentrations of P, K, Ca, and Mg obtained by multi-objective optimization of the quadratic regression models for fresh weight, SPAD value, soluble sugar content, and Vc content were 2.71 mmol·L−1, 6.42 mmol·L−1, 5.58 mmol·L−1, and 7.11 mmol·L−1, respectively. The nutrient solution formula (T1) was found to be the optimal nutrient solution formula for improving lettuce growth and quality. Overall, we developed a specific and targeted nutrient solution formulation for lettuce; this formulation not only meets lettuce’s demand for nutrients, but also improves lettuce yield and quality, providing more choices for lettuce production in a region with high salts and high pH in the irrigation water.

Methylobacterium symbioticum Applied as a Foliar Inoculant Was Little Effective in Enhancing Nitrogen Fixation and Lettuce Dry Matter Yield

Nitrogen (N) is a limiting ecological factor for plant growth in most agroecosystems. Biological N fixation, especially from nodulated legumes, has been promoted in recent decades as an alternative or complement to industrially synthesized N fertilizers. The possibility of utilizing N-fixing organisms from the phyllosphere that demonstrate effectiveness across a wide range of crops is particularly exciting. In this study, we examined the N-fixing capacity and the impact on lettuce growth of an inoculant recently introduced to the market, which contains the microorganism Methylobacterium symbioticum and is recommended for various cultivated species. A pot experiment was conducted using a factorial design, which included the inoculant (No and Yes) and four N rates (0 (N0), 25 (N25), 50 (N50), and 100 (N100) kg ha−1 of N), with four replicates, over four lettuce growing cycles. The inoculant had a significant effect on dry matter yield (DMY) only during the second of the four growing cycles. The mean values of the four growing cycles ranged from 9.9 to 13.7 g pot−1 and 9.9 to 12.6 g kg−1 in pots that received and did not receive the inoculant, respectively. On the other hand, plants exhibited a robust response to N applied to the soil, showing significant increases in both DMY and tissue N concentration across all growing cycles. Mean values of DMY in the treatments N0 and N100 ranged from 5.6 to 8.9 g pot−1 and 12.5 to 16.1 g pot−1, respectively. N concentration in tissues varied inversely with DMY, indicating a concentration/dilution effect. The difference in N concentration between treated and untreated plants, used as an estimate of fixed N, was very low for each of the soils’ applied N rates, assuming average values for the four growing cycles of −1.5, −0.9, 2.4, and 6.3 kg ha−1 for N0, N25, N50, and N100, respectively. This study emphasized the low amount of N supplied to lettuce by the inoculant and its limited effect on DMY. Generally, in biological systems with N-fixing microorganisms, achieving high fixation rates requires a high level of specificity between the microorganism and host plant, a condition that seems not to have been met with lettuce. Considering the importance of the subject, is imperative that further studies be conducted to determine more precisely in which crops and under what growing conditions the inoculant proves to be a valuable input for farmers and an effective method for reducing N mineral fertilization.

Progress on the Use of Hydroponics to Remediate Hog Farm Wastewater after Vermifiltration Treatment

Hog farm wastewater may require novel biological treatment techniques to improve efficiency and reduce costs. Previous studies combining vermifiltration with downstream hydroponics showed the need for a balanced wastewater nutrient content, particularly the nitrogen-to-phosphorus ratio. Here, a deep-water culture hydroponic system, growing lettuce as model culture, was used to remediate hog farm wastewater after an initial vermifiltration stage, aiming to produce an effluent suitable for irrigation. Supplemented vermifiltered wastewater (SVW) with added nutrients was tested against unsupplemented vermifiltered wastewater (VW) over 35 days, using a synthetic nutrient solution (NS) as a control. Supplementation was shown to improve lettuce growth, light use efficiency, and water use efficiency. Nutrient analysis over time showed a better-balanced phosphorus and nitrogen removal in SVW than in VW; in all treatments nitrogen and phosphorus content was reduced to legally acceptable levels for treated wastewater reuse in irrigation: nitrate 5 mgN L−1 in VW and undetectable in SVW and NS; ammonia undetectable in all treatments; and total phosphorus 2.4 mg L−1 in SVW, 0.9 mg L−1 in NS and undetectable in VW. Coliforms increased in VW and SVW during hydroponic treatment, which should be solved by disinfection. Overall, combining vermifiltration with downstream hydroponic culture proved to be a promising treatment to remediate nutrients in hog farm effluent to make it suitable to be reused for irrigation.

Potentialities of Technosol-isolated PGPB consortium in promoting plant growth in lettuce seedlings

Abstract Background and aims Reducing land degradation and safeguarding agricultural productions ensures the provision of ecosystem services and economic welfare, as highlighted by the 2030 Sustainable Development Goals. Among the promising solutions to tackle these issues, the study investigates the use of Technosol-isolated PGPB, as a novel approach for enhancing plant growth and the capability to cope with soil salinization. Methods Several bacteria have been isolated from a Technosol in Naples (Italy), selected to produce a consortium, based on their PGP features and tested on lettuce. The promotion of lettuce growth was evaluated both in soil (sterilized and not-sterilized Technosols) and in water agar media differing in NaCl concentrations, focusing on total polyphenols, 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging activity, soluble proteins, and sugars, which were evaluated on seedlings. Results Germination kinetics differed among treatments in both soil and artificial media setups. In the Technosol trial, the PGPB treated seeds were the quickest to emerge, showing a higher radical scavenging activity and lower soluble carbohydrate content. In the salinity trial, total soluble proteins were significantly higher in primed seeds at null saline cocentration. Conclusion Our results indicate that the PGPB application has a beneficial outcome on the Technosol but under saline stress produces an inhibitory or a costly effect on the biochemistry and germination kinetics. However, Technosol PGPBs employement may open new research scenarios on their potential application considering Nature-Based Solutions and/or plant growth in degraded environments.

Two novel heat-tolerant, culturable rhizosphere-inhabiting, plant growth-promoting ascomycete fungi associated with native plants in desert habitats of southwestern USA

During an investigations on Monosporascus cannonballus, the causal agent of root rot and vine decline of melons, in 1999, a previously unknown rhizosphere fungus was encountered in the desert soils of southern California. The fungus, herein named Desertella arida Stanghellini & Mohammadi sp. nov., was associated with roots of diverse plants including brassica (Sahara mustard (Brassica tournefortii), shepherd's purse (Capsella bursa-pastoris)) and plantain (Plantago ovata Forsk). The fungus forms extensive multinucleate, septate hyphae (6–17 μm in diameter) bearing hundreds of large spherical to pear-shaped unicellular asexual spores (50–120 μm in diameter), either singly or in large clusters. The spores are beige to cream-colored, thin-walled, and contain a dense, granular cytoplasm. Further investigation on the distribution of D. arida in soils of desert habitats in the southwestern USA led to the discovery of a second fungus belonging to a different species herein named Desertella americanense Mohammadi & Stanghellini sp. nov., in California, Arizona, Nevada, and Utah. The two species are morphologically similar. Spores from both fungi in native soil survived heat treatment up to 100 °C. Both species are culturable and colonized roots of monocots and dicots forming abundant hyphae and spores as early as 10 days post-inoculation. Desertella arida significantly enhanced shoot growth in broccoli, lettuce, Plantago ovata and flax. In conclusion, we discovered two desert-dwelling ascomycete fungi that were associated with the roots of native plant species in southern California. They were culturable on a synthetic medium, heat-tolerant and promoted growth on several crop species. These fungi appeared to exist in other neighboring states such as Arizona and Nevada.

ε-Polylysine treatment maintains sensory quality, texture, flavor, and inhibits aerobic bacteria growth in vacuum-packed fresh-cut lettuce

Quality deterioration and aroma loss of vacuum-packed fresh-cut lettuce during storage are important factors affecting its commercial value. In this study, the effects of ε-polylysine (ε-PL) on the quality and flavor attributes of vacuum-packed fresh-cut lettuce were studied. Fresh-cut lettuce was treated with different concentrations of ε-PL (0.2, 0.8, and 1.5 g L−1), vacuum-packed and stored at 4 °C for 12 d. The results showed that ε-PL treatment maintained the color and texture of fresh-cut lettuce, and reduced chlorophyll degradation and ascorbic acid loss. In addition, ε-PL treatment inhibited the growth of aerobic bacteria, and maintained or increased some aroma components such as (E)-2-hexenal, n-hexanol, hexanal, limonene, benzaldehyde. These results indicate that ε-PL treatment has potential practical application value in the preservation of vacuum-packed fresh-cut lettuce.

Effect of Different Levels of Foliar Spray of Water Soluble Fertilizer NPK on Growth, Yield and Quality of Prickly Lettuce

A trial was conducted to evaluate the foliar application of fertilizer on growth, yield &amp; quality of prickly lettuce at Vegetable Research farm, Department of Horticulture, SHUATS. The objectives of this study were to find out suitable combination of water- soluble fertilizer of nitrogen, potassium and phosphorus for growth, yield and quality of prickly lettuce and to estimate the economics of the various treatments. The experiment was laid out in randomized block design (R.B.D) with 3 replications and 8 treatments. Results revealed that treatment T4 performed best in terms of growth parameters viz; plant height, leaf area , number of leaves per plant, plant spread, leaf area , yield parameters viz; yield per plant, yield per hectare and quality parameters viz; TSS and ascorbic acid.

Impact of Physical Interventions, Phosphorus Fertilization, and the Utilization of Soil Amendments on the Absorption of Cadmium by Lettuce Grown in a Solar-Powered Greenhouse.

This study aimed to evaluate the effects of physical measures and the applications of phosphorus fertilizer and soil conditioner on the growth of lettuce (Lactuca sativa) and its uptake of cadmium (Cd). In a solar greenhouse that contained soil enriched with cadmium (Cd) (1.75 ± 0.41 mg/kg) with lettuce used as a test plant, field experimental methods were utilized to explore the influence of physical measures, such as deep plowing and soil covering, and the applications of phosphorus fertilizer, including diammonium phosphate (DAP), calcium magnesium phosphate (CMP), and calcium superphosphate (SSP), and soil conditioners, such as biochar, attapulgite clay, and nano-hydroxyapatite, on the uptake of Cd in lettuce. The results indicated that the concentrations of Cd in the aboveground parts of lettuce were 1.49 ± 0.45, 1.26 ± 0.02, 1.00 ± 0.21, and 0.24 ± 0.13 mg/kg when the soil was plowed 30, 40, and 50 cm deep, respectively, and when the soil was covered with 15 cm, this resulted in reductions of 27.5%, 38.3%, 51.4%, and 88.4%, respectively, compared with the control treatment that entailed plowing to 15 cm. When 75, 150, and 225 kg/ha of phosphorus pentoxide (P2O5) were applied compared with the lack of application, the contents of Cd in the aboveground parts of lettuce increased by 2.0%, 54.5%, and 73.7%, respectively, when DAP was applied; by 52.5%, 48.5%, and 8.1%, respectively, when CMP was applied; and by 13.1%, 61.6%, and 90.9%, respectively, when SSP was applied. When the amounts of biochar applied were 0, 2, 4, 6, 8, 10, and 12 t/ha, the contents of Cd in the aboveground parts of lettuce were 1.36 ± 0.27, 1.47 ± 0.56, 1.80 ± 0.73, 1.96 ± 0.12, 1.89 ± 0.52, 1.44 ± 0.30, and 1.10 ± 0.27 mg/kg, respectively. Under concentrations of 0, 40, 80, 120, 160, and 200 kg/ha, the application of nano-hydroxyapatite resulted in Cd contents of 1.34 ± 0.56, 1.47 ± 0.10, 1.60 ± 0.44, 1.70 ± 0.21, 1.31 ± 0.09, and 1.51 ± 0.34 mg/kg, respectively. The concentrations of Cd in the aboveground parts of lettuce treated with attapulgite clay were 1.44 ± 0.48, 1.88 ± 0.67, 2.10 ± 0.80, 2.24 ± 0.75, 1.78 ± 0.41, and 1.88 ± 0.48 mg/kg, respectively. In summary, under the conditions in this study, deep plowing and soil covering measures can reduce the concentration of Cd in the aboveground parts of lettuce. The application of phosphorus fertilizer increased the concentration of Cd in the aboveground parts of lettuce. The application of higher amounts of DAP and SSP led to greater concentrations of Cd in the aboveground parts of lettuce. The application of higher amounts of CMP caused a lower concentration of Cd in the aboveground parts of lettuce. When biochar, attapulgite clay, and nano-hydroxyapatite were applied, the concentration of Cd in the aboveground parts of lettuce increased in parallel with the increase in the concentration of application when low amounts were applied. In contrast, when high amounts were applied, the concentration of Cd in the aboveground parts of lettuce began to decrease.

Growth of Romaine Lettuce in Eggshell Powder Mixed Alginate Hydrogel in an Aeroponic System for Water Conservation and Vitamin C Biofortification.

Vitamin C is crucial for physical well-being, and its deficiency can lead to severe health consequences. Biofortification has been used to address this deficiency by enhancing vitamin C in plants. Additionally, soilless agriculture has been used to conserve and optimize water use in comparison to conventional agriculture. While hydrogels have been shown to improve water conservation and are used for biofortification in crops, their application has only been explored in soil-based and hydroponic farming. The aeroponics system is a plant-growing method that has shown potential for increasing yields and biomass while conserving water and nutrients. In this paper, we have developed an aeroponic-compatible medium to grow romaine lettuce (Lactuca sativa L.) with eggshell powder (ESP) mixed with calcium-alginate hydrogel as a substrate and nutrient source aiming to conserve water and incorporate vitamin C through biofortification. Herein, lower water spray time and higher intervals, with varied gel types and ESP concentrations, resulted in healthy lettuce growth. Plants treated with 0.5% ascorbic acid-absorbed ESP-mixed alginate hydrogel for biofortification showed higher levels of vitamin C compared to the traditional method. This study suggests using an alginate hydrogel-ESP-based substrate in aeroponics to reduce water usage and enhance plant biofortification of vitamin C.

Effects of Biochar on Growth and Pollutant Accumulation of Lettuce in Soil Co-contaminated with Tetracycline and Copper

Through lettuce potting experiments, the effects of different types of biochar (apple branch, corn straw, and modified sorghum straw biochar with phosphoric acid modification) on lettuce growth under tetracycline (TC) and copper (Cu) co-pollution were investigated. The results showed that compared with those under CK, the addition of biochar treatment significantly increased the plant height, root length, shoot fresh weight, and root fresh weight of lettuce (P &lt; 0.05). The addition of different biochars significantly increased the nitrate nitrogen, chlorophyll, and soluble protein content in lettuce physiological indicators to varying degrees, while also significantly decreasing the levels of malondialdehyde, proline content, and catalase activity. The effects of biochar on lettuce physiological indicators were consistent during both the seedling and mature stages. Compared with those in CK, the addition of biochar resulted in varying degrees of reduction in the TC and Cu contents of both the aboveground and underground parts of lettuce. The aboveground TC and Cu levels decreased by 2.49%-92.32% and 12.79%-36.47%, respectively. The underground TC and Cu levels decreased by 12.53%-55.64% and 22.41%-42.29%, respectively. Correlation analysis showed that nitrate nitrogen, chlorophyll, and soluble protein content of lettuce were negatively correlated with TC content, whereas malondialdehyde, proline content, and catalase activity were positively correlated with TC content. The resistance genes of lettuce were positively correlated with TC content (P &lt; 0.05). In general, modified biochar was found to be more effective in improving lettuce growth quality and reducing pollutant accumulation compared to unmodified biochar, with modified sorghum straw biochar showing the best remediation effect.

The Effect of Varying Olive Mill Wastewater Concentrations on Soil Free-Living Nematode Communities and Lettuce Growth

We assessed the impact of increasing olive mill waste (OMW) concentrations (10%, 35%, 70%, and 100% v/v) on soil free-living nematode communities and Lactuca sativa (lettuce) growth, 10 and 45 days after application (DAA). L. sativa plants showed a survival threshold at OMW10%, with higher concentrations proving fatal. Contrary to expectations, nematode abundance increased with OMW concentration. OMW10% induced a rapid surge in nematode abundance, stabilizing at 45 DAA, resembling control values. OMW35%, OMW70%, and OMW100% plots exhibited persistent, gradual increases, surpassing control values at 45 DAA. All treatments favored fungal feeders, resulting in the overdominance of the genus Aphelenchus both at 10 and 45 DAA. Even though OMW did not exert a toxic effect on nematode populations, this shift in the community structure towards the dominance of a single genus could suggest an imbalance in the soil community, which could have negative implications for soil health and ecosystem functioning. Overall, our study provides insights into the complex interactions between OMW, soil nematode communities, and plant growth, emphasizing the importance of understanding soil ecology for sustainable agricultural management.