Search Results (46)

Background: Equally with other indigenous green leafy vegetables, Solunum nigrum L. has been widely consumed by the VhaVenda tribe found in the Limpopo Province of South Africa since ancient times as a source of food diversification due to its higher-quality nutritional value, sustainability, food security, and medicinal benefits. It is mostly cultivated from seeds in seedling trays and transplanted in the open field, and at the maturity stage, marketing and distribution are mainly conducting through informal markets (i.e., street vendors). However, recently, it can be found in selected supermarkets and commercial grocery stores in South Africa. The leaves and young shoots of S. nigrum are cooked solely and/or as a supplementary vegetable with Brassica rapa L. subsp. chinensis (Chinese cabbage), Spinacia oleracea L. (spinach), Amaranthus graecizans L. (green amaranth), Solanum lycopersicum L. (tomato), and/or cooking oil for flavor. Objective: Contrary to other green leafy vegetables, few studies have been conducted on the metabolites released by S. nigrum and the influence of growing conditions on the metabolites thereof. Method: A ¹H-nuclear magnetic resonance tool was used to identify the untargeted metabolites released by S. nigrum, and spectra were phase-corrected and binned with MestReNova and statistically analyzed with SIMCA 18.0.2. Results: The findings showed that a total of 12 metabolites were detected between the growing conditions. Eleven similar metabolites, such as glycocholate, chlorogenate (human health benefits), caffeine for its bitter taste, choline, 3-Chlorotyrosine (antidiabetic, blood pressure), etc., and a few vital soluble sugars, were detected in S. nigrum samples grown in the open field and greenhouse-cultivated. Glucose was exclusively detected in the S. nigrum grown under greenhouse conditions. Full article

Chlorine (Cl) is an essential nutrient for higher plants, playing a critical role in their growth and development. However, excessive Cl application can be detrimental, leading to its limited use in controlled-environment agriculture. Recently, Cl has been recognized as a beneficial macronutrient, yet studies investigating its impact on plant growth and fruit quality remain scarce. In this study, we determined the optimal Cl concentration in nutrient solutions through a series of cultivation experiments. A comparative analysis of Cl treatments at 1, 2, and 3 mM revealed that 3 mM Cl⁻ significantly enhanced chlorophyll content, biomass accumulation, and yield. Furthermore, we examined the effects of 3 mM Cl⁻ (supplied as 1.5 mM CaCl₂ and 3 mM KCl) on leaf photosynthesis, chlorophyll fluorescence, and fruit sugar metabolism. The results demonstrated that Cl⁻ treatments enhanced the activity of Photosystem I (PS I) and Photosystem II (PS II), leading to a 25.53% and 28.37% increase in the net photosynthetic rate, respectively. Additionally, Cl⁻ application resulted in a 12.3% to 16.5% increase in soluble sugar content in mature tomato fruits. During fruit development, Cl⁻ treatments promoted the accumulation of glucose, fructose, and sucrose, thereby enhancing fruit sweetness and overall quality. The observed increase in glucose and fructose levels was attributed to the stimulation of invertase activity. Specifically, acidic invertase (AI) activity increased by 61.6% and 62.6% at the green ripening stage, while neutral invertase (NI) activity was elevated by 56.2% and 32.8% in the CaCl₂ and KCl treatments, respectively, at fruit maturity. Furthermore, sucrose synthase (SS-I) activity was significantly upregulated by 1.5- and 1.4-fold at fruit maturity, while sucrose phosphate synthase (SPS) activity increased by 76.4% to 77.8% during the green ripening stage. These findings provide novel insights into the role of Cl⁻ in tomato growth and metabolism, offering potential strategies for optimizing fertilization practices in protected horticulture. Full article

Digestate is primarily a by-product of anaerobic digestion, where organic waste is converted into biogas. Also, digestate has become an excellent tool for enriching the eroding and disappearing fertile soil and restoring its fertility over the past two decades. The research applying digestate as a fertilizer includes outdoor and greenhouse vegetables such as tomatoes. Antioxidants are one of the most useful substances in tomatoes. Therefore, this work aimed to evaluate the residual effect of solid grain waste digestate (below digestate) used for seedling production on the response of the antioxidant capacity of tomatoes of different fruit maturity with other assays. Tomato seedlings were grown in a peat substrate (control) and peat mixed with 5%, 10%, 15%, and 20% biogas digestate addition; fruits were harvested at three maturity levels: green growth, half-ripe, and fully ripe. From each treatment, five fruits were randomly selected at different maturity stages. This research shows that both the maturity stage and the addition of digestate may influence the antioxidant activity and total phenolic contents in tomato fruit. The digestate addition shows a significant increase in phenolics; all treatments resulted in the highest amounts during full ripening. The percentage of digestate in peat substrate and peat mixture did not have such a uniform effect as fruit maturity. The addition of 20% digestate significantly increased antioxidant activity and total phenol content in green and medium-ripe fruit; however, fully ripened fruits had similar antioxidant system responses under all digestate treatments. Full article

Contamination of aquatic and terrestrial ecosystems with microplastics (MPs) and nanoplastics (NPs) has raised significant global concerns. While most studies have focused on aquatic contamination, knowledge concerning the effect of MPs and NPs in biosolids on agricultural field crops remains limited, as is the range of polymer types tested. In this study, polyethylene nanoplastics (HDPE-NPs, <500 nm diameter) were produced in the lab, and their effect on tomato plants (Solanum lycopersicum L.) was studied at different growth stages. Physical and chemical characterizations of the HDPE-NPs were performed. Compared to the control group, the presence of 2.8 mg/kg HDPE-NPs in soil increased tomato leaf greenness (p < 0.05), while the presence of 0.5 mg/kg HDPE-NPs in the soil lowered water use efficiency (WUE, p < 0.05) of the plants in the early vegetative stage. Soil CO₂ emissions were significantly lower under both the 0.5 mg/kg (p < 0.05) and 2.8 mg/kg HDPE-NPs treatments (p < 0.05). At the early germination stage, HDPE-NPs in the soil resulted in stunted seedlings (p < 0.001). Moreover, the average fruit weight and number of fruits borne by mature plants were adversely affected, possibly because of potential alterations in soil nitrogen content and associated plant uptake pathways. A pattern of hormetic dose response was observed for some measured parameters, including leaf greenness, plant WUE, and soil CO₂ emissions, although the underlying mechanisms remain unclear. Overall, the range between 1 and 5 mg/kg concentration of HDPE-NPs in soil was found to have the greatest impact on tomato plants, while other factors may contribute to the observed effects. Full article

In arid areas, water shortage has become a major bottleneck limiting the sustainable development of agriculture, necessitating improved water use efficiency and the full development of innovative water-saving irrigation management technologies to improve quality. In the present study, tomato (Solanum lycopersicum cv. Micro Tom) fruits were used as materials, and different irrigation frequencies were set during the fruit expansion stage. The normal treatment (CK) was irrigated every three days, while the water deficit treatments were irrigated at varying frequencies: once every 4 days (T1), 5 days (T2), 6 days (T3), 7 days (T4), and 8 days (T5). These corresponded to 80%, 70%, 60%, 50%, and 40% of the maximum field moisture capacity (FMC), respectively, with CK maintaining full irrigation at 90% of the maximum FMC. The water deficit treatment T3, with less stress damage to plants and the most significant effect on fruit quality improvement, was selected based on plant growth indices, photosynthetic characteristics, chlorophyll fluorescence parameters, and fruit quality indices, and its effects on carotenoids, glycolic acid fractions, and volatile compounds during tomato fruit ripening were further investigated. The outcome indicated that moderate water deficit significantly increased the carotenoid components of the tomato fruits, and their lycopene, lutein, α-carotene, and β-carotene contents increased by 11.85%, 12.28%, 20.87%, and 63.89%, respectively, compared with the control fruits at the ripening stage. The contents of glucose and fructose increased with the development and ripening of the tomato fruits, and reached their maximum at the ripening stage. Compared to the control treatment, the moderate water deficit treatment significantly increased the glucose and fructose levels during ripening by 86.70% and 19.83%, respectively. Compared to the control conditions, water deficit conditions reduced the sucrose content in the tomato fruits by 27.14%, 18.03%, and 18.42% at the mature green, turning, and ripening stages, respectively. The moderate water deficit treatment significantly increased the contents of tartaric acid, malic acid, shikimic acid, alpha ketoglutaric acid, succinic acid, and ascorbic acid, and decreased the contents of oxalic acid and citric acid compared to the control. The contents of total soluble sugar and total organic acid and the sugar–acid ratio were significantly increased by 48.69%, 3.71%, and 43.09%, respectively, compared with the control at the ripening stage. The moderate water deficit treatment increased the fruit response values to each sensor of the electronic nose, especially W5S, which was increased by 28.40% compared to the control at the ripening stage. In conclusion, during the ripening process of tomato fruit, its nutritional quality and flavor quality contents can be significantly improved under moderate (MD) deficit irrigation treatment. The results of this experiment can lay the foundation for the research on the mechanism of water deficit aiming to promote the quality of tomato fruit, and, at the same time, provide a theoretical basis and reference for tomato water conservation and high-quality cultivation. Full article

Research on silicon (Si), an element considered beneficial for plant growth, has focused on abiotic and biotic stress mitigation. However, the effect of Si on tomato fruit quality under normal growth conditions remains unclear. This study investigated the effects of applying different levels of Si (0 mmol·L⁻¹ [CK], 0.6 mmol·L⁻¹ [T1], 1.2 mmol·L⁻¹ [T2], and 1.8 mmol·L⁻¹ [T3]) in foliar sprays on tomato fruit quality cultivated in substrates, and the most beneficial Si level was found. Compared to CK, exogenous Si treatments had a positive influence on the appearance and nutritional quality of tomato fruits at the mature green, breaker, and red ripening stages. Of these, T2 treatment significantly increased peel firmness and single-fruit weight in tomato fruits. The contents of soluble sugars, soluble solids, soluble proteins, and vitamin C were significantly higher, and the nitrate content was significantly lower in the T2 treatment than in the CK treatment. Cluster analysis showed that T2 produced results that were significantly different from those of the CK, T1, and T3 treatments. During the red ripening stage, the a* values of fruits in the T2 treatment tomato were significantly higher than those in the other three treatments. Moreover, the lycopene and lutein contents of the T2 treatment increased by 12.90% and 17.14%, respectively, compared to CK. T2 treatment significantly upregulated the relative gene expression levels of the phytoene desaturase gene (PDS), the lycopene ε-cyclase gene (LCY-E), and the zeaxanthin cyclooxygenase gene (ZEP) in the carotenoid key genes. The total amino acid content in tomato fruits in the T2 treatment was also significantly higher than that of CK. In summary, foliar spraying of 1.2 mmol·L⁻¹ exogenous Si was effective in improving the appearance and nutritional quality of tomato fruits under normal growth conditions. This study provides new approaches to further elucidate the application of exogenous silicon to improve tomato fruit quality under normal conditions. Full article

Insights into flavor formation during fruit ripening can guide the development of breeding strategies that balance consumer and producer needs. Cherry tomatoes possess a distinctive taste, yet research on quality formation is limited. Here, metabolomic and transcriptomic analyses were conducted on different ripening stages. The results revealed differentially accumulated metabolites during fruit ripening, providing candidate metabolites related to flavor. Interestingly, several key flavor-related metabolites already reached a steady level at the mature green stage. Transcriptomic analysis revealed that the expression levels of the majority of genes tended to stabilize after the pink stage. Enrichment analysis demonstrated that changes in metabolic and biosynthetic pathways were evident throughout the entire process of fruit ripening. Compared to disease resistance and fruit color genes, genes related to flavor and firmness may have a broader impact on the accumulation of metabolites. Furthermore, we discovered the interconversion patterns between glutamic acid and glutamine, as well as the biosynthesis patterns of flavonoids. These findings contribute to our understanding of fruit quality formation mechanisms and support breeding programs aimed at improving fruit quality traits. Full article

This study aimed to investigate the combined effects of temperature and light conditions on tomato maturation. Tomato fruits that had completed volumetric growth at the mature green stage were harvested and matured in growth chambers composed of two temperature conditions (daytime–nighttime: 30–20 °C or 20–15 °C) and two light conditions (0 µmol·m⁻²·s⁻¹ or 400 µmol·m⁻²·s⁻¹), which were set for 12 h each day and night. Our findings indicate that tomato ripening was significantly influenced by both light and temperature. Tomatoes that matured under low-temperature conditions in the absence of light took more than three times longer to transition from the green stage to the breaker stage compared to those matured under high-temperature conditions with light exposure. Notably, tomato fruit maturation occurred at a faster rate under low-temperature and light conditions than under high-temperature and dark conditions. Changes in chlorophyll a fluorescence parameters were observed throughout the ripening process of tomato fruits. Tomato fruits ripened under low-temperature and dark conditions exhibited significantly lower NPQ (non-photochemical quenching) and R_FD (relative fluorescence decrease) values compared to other treatments, while their F_O (initial fluorescence) and F_M (maximum fluorescence) values were higher. The accumulation of sugar in tomato fruits was observed to be more influenced by light than temperature. On the other hand, the highest levels of phenolic content and lycopene were observed in tomato fruits matured under high-temperature and light conditions. Antioxidant activities, as measured by ABTS and DPPH assays, were highest in mature tomato fruits under high-temperature and light conditions, while they were lowest in fruits under low-temperature and dark conditions. In conclusion, this study highlights the critical role of temperature and light as crucial environmental factors influencing tomato maturation. Understanding these factors can contribute to optimizing postharvest conditions and enhancing fruit quality in the tomato industry. Full article

The PLATZ (plant AT protein and zinc-binding protein) transcription factor family is involved in the regulation of plant growth and development and plant stress response. In this study, 24 SlPLATZs were identified from the cultivated tomato genome and classified into four groups based on the similarity of conserved patterns among members of the same subfamily. Fragment duplication was an important way to expand the SlPLATZ gene family in tomatoes, and the sequential order of tomato PLATZ genes in the evolution of monocotyledonous and dicotyledonous plants and the roles they played were hypothesized. Expression profiles based on quantitative real-time reverse transcription PCR showed that SlPLATZ was involved in the growth of different tissues in tomatoes. SlPLATZ21 acts mainly in the leaves. SlPLATZ9, SlPLATZ21, and SlPLATZ23 were primarily involved in the red ripening, expanding, and mature green periods of fruit, respectively. In addition, SlPLATZ1 was found to play an important role in salt stress. This study will lay the foundation for the analysis of the biological functions of SlPLATZ genes and will also provide a theoretical basis for the selection and breeding of new tomato varieties and germplasm innovation. Full article

Tomatoes are a perishable and seasonal fruit with a high economic impact. Carbon dioxide (CO₂), among several other reagents, is used to extend the shelf-life and preserve the quality of tomatoes during refrigeration or packaging. To obtain insight into CO₂ stress during tomato ripening, tomatoes at the late green mature stage were conditioned with one of two CO₂ delivery methods: 5% CO₂ for 14 days (T1) or 100% CO₂ for 3 h (T2). Conventional physical and chemical characterization found that CO₂ induced by either T1 or T2 delayed tomato ripening in terms of color change, firmness, and carbohydrate dissolution. However, T1 had longer-lasting effects. Furthermore, ethylene production was suppressed by CO₂ in T1, and promoted in T2. These physical observations were further evaluated via RNA-Seq analysis at the whole-genome level, including genes involved in ethylene synthesis, signal transduction, and carotenoid biosynthesis. Transcriptomics analysis revealed that the introduction of CO₂ via the T1 method downregulated genes related to fruit ripening; in contrast, T2 upregulated the gene encoding for ACS6, the enzyme responsible for S1 ethylene synthesis, even though there was a large amount of ethylene present, indicating that T1 and T2 regulate tomato ripening via different mechanisms. Quantitative real-time PCR assays (qRT-PCR) were used for validation, which substantiated the RNA-Seq data. The results of the present research provide insight into gene regulation by CO₂ during tomato ripening at the whole-genome level. Full article

This study introduces an effective solution to enhance the postharvest preservation of broccoli, a vegetable highly sensitive to ethylene, a hormone produced by climacteric fruits such as tomatoes. The proposed method involves a triple combination of ethylene elimination techniques: potassium permanganate (KMnO₄) filters combined with ultraviolet radiation (UV-C) and titanium oxide (TiO₂), along with a continuous airflow to facilitate contact between ethylene and these oxidizing agents. The effectiveness of this approach was evaluated using various analytical techniques, including measurements of weight, soluble solids content, total acidity, maturity index, color, chlorophyll, total phenolic compounds, and sensory analysis conducted by experts. The results demonstrated a significant improvement in the physicochemical quality of postharvest broccoli when treated with the complete system. Notably, broccoli subjected to this innovative method exhibited enhanced organoleptic quality, with heightened flavors and aromas associated with fresh green produce. The implementation of this novel technique holds great potential for the food industry as it reduces postharvest losses, extends the shelf life of broccoli, and ultimately enhances product quality while minimizing waste. The successful development and implementation of this new technique can significantly improve the sustainability of the food industry while ensuring the provision of high-quality food to consumers. Full article

SlAREB1, a member of the abscisic acid (ABA) response element-binding factors (AREB/ABFs) family, was reported to play a crucial role in the expression of ABA-regulated downstream genes and affect the ripening of tomato fruit. However, the downstream genes of SlAREB1 are still unclear. Chromatin immunoprecipitation (ChIP) is a powerful tool and a standard method for studying the interactions between DNA and proteins at the genome-wide level. In the present study, SlAREB1 was proved to continually increase until the mature green stage and then decrease during the ripening period, and a total of 972 gene peaks were identified downstream of SlAREB1 by ChIP-seq analysis, mainly located in the intergenic and promoter regions. Further gene ontology (GO) annotation analysis revealed that the target sequence of SlAREB1 was the most involved in biological function. Kyoto Encylopaedia of Genes and Genomes (KEGG) pathway analysis showed that the identified genes were mainly involved in the oxidative phosphorylation and photosynthesis pathways, and some of them were associated with tomato phytohormone synthesis, the cell wall, pigment, and the antioxidant characteristic of the fruit as well. Based on these results, an initial model of SlAREB1 regulation on tomato fruit ripening was constructed, which provided a theoretical basis for further exploring the effects of the regulation mechanism of SlAREB1 and ABA on tomato fruit ripening. Full article

Due to the dense distribution of tomato fruit with similar morphologies and colors, it is difficult to recognize the maturity stages when the tomato fruit is harvested. In this study, a tomato maturity recognition model, YOLOv5s-tomato, is proposed based on improved YOLOv5 to recognize the four types of different tomato maturity stages: mature green, breaker, pink, and red. Tomato maturity datasets were established using tomato fruit images collected at different maturing stages in the greenhouse. The small-target detection performance of the model was improved by Mosaic data enhancement. Focus and Cross Stage Partial Network (CSPNet) were adopted to improve the speed of network training and reasoning. The Efficient IoU (EIoU) loss was used to replace the Complete IoU (CIoU) loss to optimize the regression process of the prediction box. Finally, the improved algorithm was compared with the original YOLOv5 algorithm on the tomato maturity dataset. The experiment results show that the YOLOv5s-tomato reaches a precision of 95.58% and the mean Average Precision (mAP) is 97.42%; they are improved by 0.11% and 0.66%, respectively, compared with the original YOLOv5s model. The per-image detection speed is 9.2 ms, and the size is 23.9 MB. The proposed YOLOv5s-tomato can effectively solve the problem of low recognition accuracy for occluded and small-target tomatoes, and it also can meet the accuracy and speed requirements of tomato maturity recognition in greenhouses, making it suitable for deployment on mobile agricultural devices to provide technical support for the precise operation of tomato-picking machines. Full article

The effect of isonicotinic acid (INA) in a chitosan (CS)/polyvinyl alcohol (PVA) blend on ripening-dependent changes of preserved green tomatoes (Solanum lycopersicum L.) was examined at room temperature. The results showed that CS/PVA/INA 0.5 mM and CS/PVA/INA 1.0 mM formulations retarded firmness loss and delayed the pigmentation parameters i.e., lycopene (LYP), total carotenes (TCs), and titratable acidity (TA). The CS/PVA/INA 0.5 mM and CS/PVA/INA 1.0 mM formulations were able to delay the increase in malondialdehyde (MDA) and total polyphenol (TP) contents. Furthermore, the peroxidase (POD), polyphenoloxidase (PPO), and phenylalanine ammonia-lyase (PAL) activities of tomatoes coated with CS/PVA/INA 0.5 mM and CS/PVA/INA 1.0 mM formulations were lower than those in other treatments. Meanwhile, the CS/PVA blend had the highest TP content, as well as the highest PPO and PAL activities, at the late stage of maturation. The UV analysis showed that the CS/PVA/INA blend film is a promising UV-protective food packaging material. The pure CS, PVA, and INA formulations, as well as the CS/PVA, CS/PVA/INA 0.5 mM, and CS/PVA/INA 1.0 mM formulations, were characterized by infrared (FTIR). The three polymer formulations showed strong antifungal activity against Alternaria alternata and Botrytis cinerea. Full article

The production of tomato under low-temperature stress in the open fields is a challenge faced by many farmers. The current study compares the use of different ethylene treatments to accelerate the fruit ripening of tomato during two successive seasons under cold stress. The treatments included foliar application of ethrel (2500, 5000, and 7500 ppm) in the open field at the mature green stage, dipping collected fruits in ethrel solution (1000, 1500, and 2000 ppm) right after harvest, and application of gaseous ethylene (100, 200, and 300 ppm) to the harvested fruits. The effects were compared to untreated fruits (control). Characteristics, such as physical properties (ripening, weight loss, firmness, decay, and fruit color), chemical properties (ascorbic acid, acidity, total soluble sugars, and pigments), and enzymatic activities (polygalacturonase and pectin methylesterase), were sampled throughout the storage period. In general, the ethylene gas application was the most effective method in accelerating the fruit ripening process compared to the other methods applied. The highest vitamin C total soluble solid contents and redness parameters were found after applying the highest dose of ethylene gas (300 ppm). This indicates that the ripening of tomato fruits, which are cultivated under cold stress conditions as found during the early summer season in a Mediterranean climate, might be harvested at a mature green stage and exposed to ethylene application. Full article