Leaf Lettuce Research Articles

Light Intensity Modulates the Functional Composition of Leaf Metabolite Groups and Phyllosphere Prokaryotic Community in Garden Lettuce (Lactuca sativa L.) Plants at the Vegetative Stage.

Light intensity primarily drives plant growth and morphogenesis, whereas the ecological impact of light intensity on the phyllosphere (leaf surface and endosphere) microbiome is poorly understood. In this study, garden lettuce (Lactuca sativa L.) plants were grown under low, medium, and high light intensities. High light intensity remarkably induced the leaf contents of soluble proteins and chlorophylls, whereas it reduced the contents of leaf nitrate. In comparison, medium light intensity exhibited the highest contents of soluble sugar, cellulose, and free amino acids. Meanwhile, light intensity resulted in significant changes in the composition of functional genes but not in the taxonomic compositions of the prokaryotic community (bacteria and archaea) in the phyllosphere. Notably, garden lettuce plants under high light intensity treatment harbored more sulfur-cycling mdh and carbon-cycling glyA genes than under low light intensity, both of which were among the 20 most abundant prokaryotic genes in the leaf phyllosphere. Furthermore, the correlations between prokaryotic functional genes and lettuce leaf metabolite groups were examined to disclose their interactions under varying light intensities. The relative abundance of the mdh gene was positively correlated with leaf total chlorophyll content but negatively correlated with leaf nitrate content. In comparison, the relative abundance of the glyA gene was positively correlated with leaf total chlorophyll and carotenoids. Overall, this study revealed that the functional composition of the phyllosphere prokaryotic community and leaf metabolite groups were tightly linked in response to changing light intensities. These findings provided novel insights into the interactions between plants and prokaryotic microbes in indoor farming systems, which will help optimize environmental management in indoor farms and harness beneficial plant-microbe relationships for crop production.

Prevalence and Antimicrobial Characteristics of Escherichia coli in Selected Vegetables and Herbs in Bangkok, Thailand

Raw vegetables and herbs are exposure sources of foodborne pathogens. This study examined the prevalence and antimicrobial resistance of Escherichia coli in five types of fresh vegetables and herbs: spearmint (Mentha spicata), leaf lettuce (Lactuca sativa var. crispa), coriander (Coriandrum sativum), Chinese cabbage (Brassica rapa subsp. pekinensis), and cucumber (Cucumis sativus). Produce samples (n = 300) were acquired from local open markets and supermarkets in Bangkok, Thailand. Each produce sample was preenriched in buffered peptone water and then enriched in E. coli broth. A loopful of the second enrichment was transferred onto selective media for subsequent confirmation and biochemical tests. The Kirby-Bauer disk diffusion test was employed to assess E. coli susceptibility to selected antibiotics (twelve antibiotics of seven classes). The latex agglutination test was performed to serotype the isolates for O157 and H7 antigens. A commercial test kit was used to determine the presence of Shiga toxin-producing E. coli (STEC). For all samples, the prevalence of E. coli was found to be 32.0% (96/300), whereby produce from supermarkets had a higher prevalence than those from local markets at 40.7% (61/150) and 23.3% (35/150), respectively. Among different types of produce, leaf lettuce had the highest E. coli prevalence at 36.7% (22/60), followed by cucumber and spearmint, coriander, and Chinese cabbage, at 35.0% (21/60), 35.0% (21/60), 35.0% (21/60), and 18.3% (11/60), respectively. Of the positive isolates, 27.1% (26/96) showed multidrug resistance. All isolates (100%) showed resistance to penicillin but varying resistant characteristics for tetracycline, ampicillin, and amoxicillin, with resistance rates of 31.3% (30/96), 31.3% (30/96), and 31.3% (30/96), respectively. Two of the 96 isolates (1.1%) were positive for the O157 antigen but negative for the H7 antigen. No STEC was observed. This study established baseline information regarding the prevalence of E. coli and its antimicrobial resistance profile in produce in Bangkok, Thailand.

FEATURES OF THE GROWTH AND DEVELOPMENT OF LETTUCE PLANTS SOWED UNDER HYDROPONIC GROWING

Research is devoted to the study of the assortment of lettuce seeded under hydroponics conditions. The survival rate of lettuce plants depended on the type and variety, and also differed to a certain extent by the terms of sowing. Plants of the Aficion variety of leaf lettuce (control) had the highest percentage of engraftment - 98.1%, which is 0.6 and 3.7% more compared to other variants of the experiment. Plants of the Raphael variety had a higher survival rate in romaine lettuce – 97.9%, which is 1.4% more than the control variant. Among the varieties of romaine lettuce, plants of the Maximus variety (control) had a higher height – 16.1 cm, which is 3.8 cm more than the Raphael variety. Comparing leaf lettuce plants, the highest height was noted in the Aficion variety (control) – 13.3 cm, which is 0.9 and 1.8 cm more than the other tested variants. In romaine lettuce, a larger diameter of the rosette was noted in the Maximus variety – 25.2 cm, which is 9.1 cm more than the Raphael variety. Among the leaf-type lettuce varieties, the largest diameter of the rosette of leaves was characterized by plants of the Aficion variety (Batavia type) – 28.3 cm, which is 4.0 and 7.9 cm more than the other studied variants of the experiment. In romaine lettuce, plants of the Maximus variety were characterized by a greater mass of the above-ground part – 210 g, which is 80.0 g more than the Raphael variety. Among the varieties of leaf lettuce, the Kirinia variety had the largest mass – 200 g, which is 60.0 more than the control variant. Mr. Maximus variety romaine lettuce had the highest yield – 9.3 kg/m2, and in terms of rows – 37.0 kg/m2, which is 14.1 kg/m2 more than the Raphael variety. Among the leafy types of lettuce, plants of the Kirinia variety were characterized by a higher yield – 8.8 kg/m2, in terms of rows – 35.2 kg/m2, where the increase compared to the control was 10.6 kg/m2. The yield of different types of lettuce ranged from 158.4 t/ha to 369.6 t/ha, taking into account the rows of racks. The highest yield, taking into account the tiering of racks, was obtained by growing Maximus (romaine type) – 369.6 t/ha and Kirinia (oak type) – 352.0 t/ha with an increase of 42.9 t/ha compared to the control variant.

Biofortificação foliar com nanopartículas de cobre e seu efeito na qualidade fitoquímica e atividade enzimática em alface

ABSTRACT The objective of this study was to evaluate the foliar application of copper oxide nanoparticles (NPs-CuO) on the phytochemical quality, yield, catalase and peroxidase activity of the hydroponic lettuce crop. Five concentrations (5, 10, 15, 20 and 25 mg/L) of NPs-CuO and a control (0 mg/L) were compared. The experiment was established in a completely randomized design with five repetitions. Data were analyzed with analysis of variance and mean comparisons using Tukey's test (0.05). The results indicate that, under the hydroponic conditions, the lettuce plants showed a greater number of leaves, leaf width and the peroxidase enzyme activity was recorded with the concentration of 15 mg/L NPs-CuO. The concentration of 10 mg/L of NPs-CuO yielded higher contents of total phenols, total flavonoids and antioxidant capacity, being 46.63, 34.21 and 28.23% higher compared to the control treatment, respectively. Regarding the concentration of Cu in the lettuce leaf, the 20 mg/L treatment showed the highest concentration with a value of 9.93±2.40 µg/L DW. The use of copper nanoparticles could be an effective alternative to mitigate copper deficiency in the diet of the human population.

Increased expression of GLUT4, catalase and nitric oxide by a crystalised fraction from ethanolic extracts of oak leaf lettuce and okra seed in C2C12 cell line

The fractions obtained from low temperature-induced crystallisation of ethanolic extracts of green- and red-oak leaf and okra seed were accounted for total polyphenol content and the DPPH antioxidant activity, resulting in 5.99, 4.44, and 12.35 mg gallic acid equivalent per g sample, and 0.45, 0.35, and 0.99 mg Trolox equivalent per g sample, respectively. Insulin resistance was the result after incubating C2C12 skeletal muscle cells in high glucose DMEM for 20 h. Oxidative stress and inflammation were triggered by re-incubating these resistant cells with insulin. The expression of p-p38 MAPK and NF-B proteins and the NF-B p65 transcription factor activity were enhanced. Such inflammatory protein markers were reduced when the crystalised extracts replaced insulin. Increased catalase activity and NO production were also determined for the incubations using the crystalised extracts. It was suitable to include these vegetables in the daily diets of prediabetic individuals for better management of the patient’s health status by increasing insulin sensitivity and decreasing inflammation.

Effect of Seed Pelleting Application of Plant Growth Promoting Bacteria on Germination and Growth of Lettuce (Lactuca sativa)

Plant growth-promoting bacteria (PGPB) are commonly used to pellet seeds. Different bacterial strains affect germination and plant growth in varying ways. The objective of this experiment was to study the effects of seed pelleting with three strains of bacteria on changes in germination, vigor, seedling growth, and the plant growth of lettuce. The experiment followed a completely randomized design with four repetitions and five treatments: without pelleting (T1), pelleting with CaSO4-zeolite only (T2), pelleting with 1×107 CFU/mL Stenotrophomonas sp. strain sk3 (T3), pelleting with 1×108 CFU/mL Burkholderia sp. strain 3-DB05 (T4), and pelleting with 1×108 CFU/mL Enterobacter sp. strain 4-RB05 (T5). Burkholderia sp. and Enterobacter sp. were more effective in producing indole-3-acetic acid (IAA), and pelleting seeds with these strains resulted in higher germination rates and seedling growth compared to unpelleted seeds when tested in both laboratory and greenhouse conditions. Seed pelleting with 1×108 CFU/mL Enterobacter sp. promoted plant growth and resulted in significantly higher leaf and root weight. Therefore, seed pelleting with 1×108 CFU/mL Enterobacter sp. strain 4-RB05 is recommended to improve the germination and plant growth of Red Oak Leaf lettuce seeds.

Plants Wilt Disease of Red Leaf Lettuce (Lactuca sativa L.) After Colonized by Trichoderma longibrachiatum

Trichoderma longibrachiatum rarely reported can cause disease in plants. The present study investigates the pathogenicity of T. longibrachiatum isolate UPMT14 on the red leaf lettuce (Lactuca sativa L.) plants grown in sterile soil under a controlled growth room environment. The fungal isolate was initially characterized morphologically as Trichoderma sp. and was then further characterized by (ITS) region sequencing and BLAST comparison identified as T. longibrachiatum. To observe the response of Trichoderma isolate UPMT14 when imposed on lettuce plants. The injection was made and repeated five times, and then the lettuce growth followed for 36 days. On day 36, the present study found that the red leaf lettuce plants expressed foliar symptoms that began as chlorotic, reduced plant height, reduced leaf length and diameter, wilt, and dried up before it collapsed at day 45 compared to untreated control lettuce plants. Microscopic observation on lettuce roots showed that the Trichoderma spores invading the root system by mass sporulation and spatial competition possibly impaired plant water uptake and eventually caused plant wilting. Therefore, this study indicates that T. longibrachiatum is among the causal agents of wilt disease in the lettuce plant.

Growth and Development of Leaf Vegetable Crops under Conditions of the Phytotechnical Complex in Antarctica

Ensuring the technical and technological possibility of regularly obtaining fresh, high-quality plant production in Antarctic stations is an urgent task of our time. This work is devoted to studying the growth and development of leaf vegetable crops and the main quality indicators of their edible parts when grown in the phytotechnical complex greenhouses at the “Vostok” Antarctic station and at the agrobiopolygon of the Agrophysical Research Institute (AFI). The plants, belonging to 13 varieties of 9 types of leaf vegetable crops (arugula, garden cress, cabbage, mustard, leaf radish, leaf lettuce, amaranth, dill, parsley leaf), were studied during five growing seasons at the “Vostok” station and at the AFI agrobiopolygon under controlled conditions (control). The experimental data obtained demonstrate the high productivity of the phytotechnical complex for most of the investigated crops per unit of useful area, with lower costs of electricity and water consumption per unit of production compared with a number of greenhouses at foreign Antarctic stations and greenhouse complexes with controlled conditions located on other continents. Lettuce crops were the most adapted to the growing conditions at the Antarctic station “Vostok”. They did not differ in their evaluated characteristics from the control. All other investigated crops, while not differing in their development rate and quality, had statistically significant (16–61%) decreases in their yield per 1 m2 per year. This may demonstrate the difference in the “genotype–environment” interaction in plants grown at the Antarctic station and AFI agrobiopolygon, probably due to the different barometric pressure and partial pressure of oxygen at the two locations. The positive psychological effects of the greenhouses were identified along with nutritional and other qualities of the plants.

Phytochemical contents and diuretic activity of ethanolic extract of the red leaf lettuce (Lactuca Sativa l.)

This study was conducted to evaluated of phytochemical content and diuretic activity of the red leaf lettuce. Red leaf lettuce were extracted by cold maceration method using 70% ethanol for the 3 days and remaceration for 1 days. The phytocemical content in ethanolic extract were evaluated by qualitatif method. A total of 25 male rats were divided into 5 groups with CMC Na, a standard drug (furosemide 10 mg/kg), and three different doses (200, 300, and 400 mg/kg) of ethanol extract. Parameters used to determine diuresis activity include first urine latency, urine pH and cumulative urine volume. The ethanolic extract induced diuresis in a dose dependent manner as compared to the negative control. Extracts at doses of 200, 300, and 400 mg/kg produced significant diuresis effects (p<0.05) compared to negative controls with values of diuretic action 1.35; 1.43; and 1.53, respectively. In addition, there was a slightly change in the pH of urine samples of the extract-treated group compared with the negative control. Phytochemicals analysis revealed the presence of alkaloids, flavonoids, phenolics, and tannins.

The Consumption of Iceberg Lettuce May Reduce The Adhesion of Dietary Fat to The Mucus Surface of The Stomach Barrier Lining Decreasing The Risk of Triggering Acute Gastroesophageal Reflux

Iceberg lettuce (IL) leaves contain surface epicuticular waxes that can adsorb significant quantities of dietary fat per unit weight. Fats such as olive oil, butter, lamb fat and lard readily adsorb onto IL with soft solid fats contained in lamb fat and lard, showing strong adhesion and more resistance to removal on rinsing in a water stream. Dishwashing detergents containing surfactants prevent the adsorption of both liquid and solid fats to the lettuce leaf surface, unless at very low concentrations, highlighting their significant influence on surface properties. Based on the adhesion of fats to the IL leaf surface, it is proposed the consumption of IL could reduce acute gastroesophageal reflux (GER) and the development of gastroesophageal reflux disease (GERD). In diets containing fat, the adhesion to IL reduces the amount of fat available to adhere to the mucus surface of the stomach barrier lining, protecting the lining and reducing access by trigger foods to underlying surfaces that could potentially initiate GER.

Far-red light and temperature interactively regulate plant growth and morphology of lettuce and basil

Both the spectral quality of light, particularly the ratio of red (R; 600–700 nm) to far-red light (FR; 700–800 nm), and temperature can regulate phytochrome activities, subsequently influencing plant growth and morphology. However, our understanding of how light quality and temperature interact to control phytochrome-mediated morphological responses is largely limited to hypocotyl elongation in Arabidopsis seedlings. In this study, we quantified the interactive effects between FR light and temperature on morphological traits of agronomic and horticultural significance in two crops with contrasting morphology and growth habits, lettuce (Lactuca sativa L.) ‘Rex’ and basil (Ocimum basilicum) ‘Genovese’. Plants were grown under blue (B), green (G), R, and FR LED light with three spectral treatments [B25G25R200 (0%FR), B25G25R175FR25 (10%FR), B25G25R150FR50 (20%FR); the subscript represents photon flux density in μmol m−2 s−1] and five temperature regimes [Day (℃)/Night (℃); 20/20, 24/24, 28/28, 20/28 (–DIF), 28/20 (+DIF); DIF represents differential day/night temperature]. Total photon flux density in each spectral treatment was 250 μmol m−2 s−1 (400–800 nm; 12-h photoperiod). As FR light percentage and temperature increased, leaf length and plant height increased in both species. However, the effects of FR light and temperature were interdependent. Specifically, the stimulative effects of FR light on extension growth generally diminished under warmer temperatures and in the –DIF treatment (20/28 ℃). Total leaf area increased with increasing FR percentage under 20/20 and 24/24 ℃ treatments in both lettuce and basil. However, under 28/28 ℃, increasing the FR percentage from 0% to 20% caused a decrease in lettuce leaf area while having no effect on basil leaf area. Similar to responses in total leaf area, dry biomass significantly increased with increasing FR percentage under cooler temperatures. Under warm temperature of 28/28 ℃, dry biomass decreased with increasing FR percentage in lettuce, whereas no significant difference was observed in basil. Due to the interaction between FR and temperature, phytochrome photoequilibrium (PPE) estimated from photoconversions alone was less predictive of plant morphology under varying temperature conditions. Those results indicate that light spectrum and temperature interactively regulate the activity of phytochromes, plant morphology, and subsequent plant growth in both lettuce and basil, and thus should be co-optimized in controlled environment crop production systems.

Influence of Soil and Nutrient Management Practices on Crop Productivity and Quality in High Tunnel Organic Leafy Green Production

Despite the growing interest in high tunnel organic vegetable production, limited information is available regarding optimizing nutrient management for organic leafy greens. This 3-year study examined the impacts of cowpea cover crop as well as different organic fertilizers and composts on yield, leaf mineral nutrient content, and phytochemical properties of organic leafy greens produced in high tunnels under Florida sandy soil conditions. The experiment was arranged in a split-split-plot design with three replications. The whole plots consisted of a cowpea (Vigna unguiculata ‘Iron & Clay’) cover crop and a weedy fallow control, with fertilization treatments in the subplots, including preplant application of granular fertilizer vs. weekly injection of liquid fish fertilizer at the same seasonal rates of nitrogen (112 kg/ha), phosphorus (9.8 kg/ha), and potassium (74.4 kg/ha). The sub-subplots included yard waste-based compost (22.4 Mt/ha), cow manure-based compost (22.4 Mt/ha), vermicompost (5.6 Mt/ha), and no compost control. Cowpea was broadcasted (112 kg/ha) in early July or mid-August and terminated 51 to 53 days after seeding. Pac choi (Brassica rapa var. chinensis ‘Mei Qing Choi’) was transplanted in mid-Sep. or mid-Oct. and harvested after 33 to 36 days. Baby spinach (Spinacia oleracea ‘Corvair’) or baby leaf lettuce (Lactuca sativa ‘Outredgeous’) was direct seeded subsequently as a catch crop. Each experimental unit remained in the same location across the 3 years of the study. Cover cropping had little influence on yields, leaf mineral nutrients, ascorbic acid content, total phenolics, and total antioxidant capacity of pac choi and baby spinach/lettuce. Compared with preplant application of the granular organic fertilizer, weekly liquid organic fertigation improved pac choi marketable yield and dry weight by 16.8% and 5.4% on average, respectively, and enhanced leaf nitrogen and phosphorus contents on a dry weight basis. Relative to the no compost control, yard waste compost consistently improved marketable yields of pac choi by 11.6% on average and led to higher yields of the baby spinach/lettuce catch crop in years 1 and 3, suggesting that compost applications may enhance seasonal nutrient availability to better meet crop demand. However, compost application exhibited inconsistent effects on crop mineral nutrient and phytochemical contents across the years, which could be attributed to the different nutrient compositions of the composts applied in each season, as well as the legacy effects from the previous season. Furthermore, the compost benefits may be influenced by the fertilization program as indicated by their interaction effects observed in this study.

Fates of attached E. coli o157:h7 on intact leaf surfaces revealed leafy green susceptibility

Leafy greens, especially lettuce, are repeatedly linked to foodborne outbreaks. This paper studied the susceptibility of different leafy greens to human pathogens. Five commonly consumed leafy greens, including romaine lettuce, green-leaf lettuce, baby spinach, kale, and collard, were selected by their outbreak frequencies. The behavior of E. coli O157:H7 87-23 on intact leaf surfaces and in their lysates was investigated. Bacterial attachment was positively correlated with leaf surface roughness and affected by the epicuticular wax composition. At room temperature, E. coli O157:H7 had the best growth potentials on romaine and green-leaf lettuce surfaces. The bacterial growth was positively correlated with stomata size and affected by epicuticular wax compositions. At 37 °C, E. coli O157:H7 87-23 was largely inhibited by spinach and collard lysates, and it became undetectable in kale lysate after 24 h of incubation. Kale and collard lysates also delayed or partially inhibited the bacterial growth in TSB and lettuce lysate at 37 °C, and they sharply reduced the E. coli O157:H7 population on green leaf lettuce at 4 °C. In summary, the susceptibility of leafy greens to E. coli O157:H7 is determined by a produce-specific combination of physiochemical properties and temperature.

Appropriate Nitrogen form Ratio and UV-A Supplementation Increased Quality and Production in Purple Lettuce (Lactuca sativa L.)

Purple lettuce (Lactuca sativa L. cv. Zhongshu Purple Lettuce) was chosen as the trial material, and LED intelligent light control consoles were used as the light sources. The purpose was to increase the yield and quality of purple lettuce while lowering its nitrate level. By adding various ratios of NO3−-N and NH4+-N to the nutrient solution and 20 µmol m−2 s−1 UV-A based on white, red, and blue light (130, 120, 30 µmol m−2 s−1), the effects of different NO3−-N/NH4+-N ratios (NO3−-N, NO3−-N/NH4+-N = 3/1, NH4+-N) and UV-A interaction on yield, quality, photosynthetic characteristics, anthocyanins, and nitrogen assimilation of purple lettuce were studied. In order to produce purple lettuce hydroponically under controlled environmental conditions, a theoretical foundation and technological specifications were developed, taking into account an appropriate UV-A dose and NO3−-N/NH4+-N ratio. Results demonstrate that adding a 20 µmol m−2 s−1 UV-A, and a NO3−-N/NH4+-N treatment of 3/1, significantly reduced the nitrate level while increasing the growth, photosynthetic rate, chlorophyll, carotenoid, and anthocyanin content of purple lettuce. The purple leaf lettuce leaves have an enhanced capacity to absorb nitrogen. Furthermore, plants have an acceleration of nitrogen metabolism, which raises the concentration of free amino acids and soluble proteins and promotes biomass synthesis. Thus, based on the NO3−-N/NH4+-N (3/1) treatment, adding 20 µmol m−2 s−1 UV-A will be helpful in boosting purple lettuce production and decreasing its nitrate content.

Development, Verification, and Analysis of Simple Mathematical Model of Lettuce Productivity under Different Light Conditions

Lettuce is an important agricultural plant which is often cultivated under artificial illumination including light of light emitting diodes (LEDs). Spectrum and intensity of used illumination and duration of photoperiod can strongly influence a final lettuce biomass; their effects can be interacted. It means that search of optimal light conditions is complicated problem for experimental investigations because numerous combinations of light conditions should be analyzed. A mathematical model of lettuce productivity can provide the potential tool for intensification of this search; earlier, we preliminarily proposed the minimal model of lettuce productivity under the LED illumination. The aim of the current work was further development, verification, and analysis of the simple mathematical model of the lettuce productivity. Dry weight of a lettuce leaf rosette was used as the main variable of the model; its changes were described as function of difference between production of biomass through assimilation and its consumption through respiration. The model was quantitively parameterized and verified on basis of our previous experimental works devoted to influence of parameters of the LED illumination on lettuce characteristics. It was shown well correspondence between experimental and simulated results. Further analysis of the developed model predicted optimal illumination conditions of the lettuce cultivation. Particularly, it showed a positive influence of gradual and step increase of the light intensity on final biomass of cultivated lettuce plants. Thus, the developed model can be used as the tool for the theoretical prediction of optimal light conditions for the lettuce cultivation.

Foliar spraying of lanthanum activates endocytosis in lettuce (Lactuca sativa L.) root cells, increasing Cd and Pb accumulation and their bioaccessibility

Cadmium (Cd) and lead (Pb) accumulate easily in leafy vegetables and can harm human health. Lanthanum (La) have been used to improve agricultural yield and quality, but the effect of La application on Cd/Pb enrichment in leafy vegetables remains incomplete currently. A previous study reported that the endocytosis in lettuce leaf cells can be activated by La, leading to an increase in Pb accumulation in lettuce leaves. However, it has not been investigated whether foliar application of La enhances root cellular endocytosis and promotes its uptake of Cd and Pb. In this study, the influence of La on the uptake of Cd and Pb, Cd bioaccessibility, and the safety risks of cultivating lettuce under Cd and Pb stress were explored. It was found that La increased Cd (16–30 % in shoot, 16–34 % in root) and Pb (25–29 % in shoot, 17–23 % in root) accumulation in lettuce. The increased accumulation of Cd and Pb could be attributed to La-enhanced endocytosis. Meanwhile, La enhanced the toxicity of both Cd and Pb, inhibited lettuce growth, and aggravated the damage to the photosynthetic and antioxidant systems. Finally, gastrointestinal simulation experiments showed that La increased the Cd bioaccessibility in both gastric and intestinal phase by 7–108 % and 9–87 %, respectively. These results offer valuable insights into the safety of REEs for agricultural applications.

Prediction of the breeding value of leaf lettuce mutant lines according to the correlation between the manifestation of qualitative and quantitative traits

Aim. To establish the effect of mutagenic factors on the formation of qualitative traits, defining the phenotype of the leaf blade, and to investigate the correlation between the manifestation of these factors and the variation of quantitative traits of breeding value in mutant lines of leaf lettuce. Methods. Non-parametric statistical and criteria of difference for biological specimens, computational and analytical calculations, correlation analysis. Results. The comparative analysis was conducted on the qualitative characteristics of the original leaf blade form of leaf lettuce, Zhnych variety, alongside 14 mutant lines derived from it through the application of mutagenic agents, including dimethyl sulfate (DMS) and its derivatives (D3MU, DMU-10А, and DMU-9) in two varying concentrations. Notably, the derivatives of DMS exhibited superior mutagenic efficiency, leading to a four to fivefold increase in the number of mutant plant forms compared to the reference compound DMS. Among the derivatives, D3MU proved the most effective, generat- ing five mutant lines. In contrast, DMU-10A and DMU-9 yielded four mutant lines, while DMS produced only one mutant line. All mutant lines exhibited distinct variations from the initial form across 17 qualitative characteristics determining leaf blade phenotype. The analysis of Spearman’s rank correlation coefficient (rs) demonstrated weak to moderate correlation (rs = –0.08...0.62) between the original form and mutant lines. It was determined that three lettuce lines, namely B-7, B-22, and B-38, exhibited the most significant deviations from the initial form in term of leaf blade qualitative traits. Furthermore, it was established that non-parametric indicators of qualitative traits expression exhibited moderate or high correlation (rs = 0.57...0.74) with an essential quantitative trait – the duration from the emergence of mass shoots to plant stem development in mutant lines. Conclusions. The identified correlations between quantitative and qualitative traits provide the opportunity to predictably select mutant genotypes with extended growth period during the early stages of lettuce plant ontogenesis in future breeding work.

Comparison of Convolutional Neural Network (CNN) Models for Lettuce Leaf Width and Length Prediction

Comparison of Convolutional Neural Network (CNN) Models for Lettuce Leaf Width and Length Prediction

Effect of co-presence of cadmium or procymidone with microplastic films in soil on lettuce growth

Agricultural environment is often contaminated with various chemicals (e.g., pesticides, heavy metals) and microplastics due to the uses of plastic products. The effects of chemical contaminants or microplastics on terrestrial environment have been extensively studied, but the studies on the co-presence of chemical contaminants and microplastics are relatively limited. This study was set to investigate the effect of co-presence of microplastics (i.e., low-density polyethylene (LDPE) and polyvinyl chloride (PVC) microplastic films) and chemical contaminants (i.e., cadmium (Cd) and procymidone (PCM)) in soil on the lettuce growth and Cd and PCM uptake by lettuce using pot tests. The lettuce leaf lengths were not affected by the presence of only Cd or PCM, but the rates of change in the lettuce leaf number were adversely affected by the presence of PCM. The presence of only LDPE or PVC in soil at the concentrations used in this study did not have significant impacts on the lettuce growth. But the co-presence of Cd and LDPE and the co-presence of PCM and PVC resulted in the negligible increases in the lettuce leaf length and leaf number with time, although the lettuce growths were statistically similar in the Cd- or PCM-contaminated soils regardless of the presence of microplastics. The results suggest that the adverse effects of Cd or PCM can be intensified by the co-presence of microplastics, and the effects can be different depending on the types of microplastics. The promoted adverse effects of chemical contaminants in the co-presence of microplastics can be supported by the tendency of the increased absorption of Cd or PCM by lettuce in the co-presence of microplastics. Overall, this study shows the need for management of both chemical contaminants and microplastics that may reside in the agricultural environment.

Relief from Salt Stress by Plant Growth-Promoting Bacteria in Hydroponic Leaf Lettuce (Lactuca sativa L.)

Relief from Salt Stress by Plant Growth-Promoting Bacteria in Hydroponic Leaf Lettuce (Lactuca sativa L.)