Search Results (212)

In establishing the safety or tolerability profile of bioactive plant extracts, it is important to perform toxicity studies using appropriate, accessible, and sustainable methods. The Allium cepa model is well known and frequently used for accurate environmental risk assessments, as well as for evaluating the toxic potential of the bioactive compounds of plant extracts. The present review focuses on this in vivo cytogenetic model, highlighting its widespread utilization and advantages as a first assessment in monitoring the genotoxicity and cytotoxicity of herbal extracts, avoiding the use of animals for testing. This plant-based assay allows for the detection of the possible cytotoxic and genotoxic effects induced on onion meristematic cells. The outcomes of the Allium cepa assay are comparable to other tests on various organisms, making it a reliable screening test due to its simplicity in terms of implementation, as well as its high sensitivity and reproducibility. Full article

Excessive fertilization is a widespread issue in onion (Allium cepa L.) production in Southwest China. This practice not only leads to environmental pollution but also decreases the marketable yield and fertilizer productivity of onions. Identifying an optimal fertilization rate is crucial for promoting high-yield and highly efficient onion cultivation. The objective of this research is to determine the appropriate amount of fertilizer by investigating the effects of different fertilization rates on the growth characteristics and bulb yield of onion. The study was conducted over two consecutive growing seasons utilizing a randomized complete block design, which included six treatments: local routine fertilizer application (F1), a 20% reduction from F1 (F2), a 40% reduction from F1 (F3), a 60% reduction from F1 (F4), an 80% reduction from F1 (F5), and no fertilizer application (F0). The results show that, at the mature stage, aboveground dry matter quantity and its accumulation rate of onion under treatment F2 were found to be the highest among all other treatments across both growing seasons. Following the onset of bulbing, dry matter accumulation initially increased but subsequently decreased with reduced fertilizer supply; notably, it was greater under treatment F2 compared to other treatments. Compared with F1, the PFPN (partial factor productivity of nitrogen fertilizer) under treatment F2 increased by 35.2% and 32.0%, and the marketable bulb yield under treatment F2 increased by 8.4% and 5.8% during the 2022–2023 and 2023–2024 growing seasons, respectively. The marketable bulb yield demonstrated extremely significant positive correlations with aboveground dry matter and the dry matter accumulation rate throughout all growth periods in both growing seasons. Furthermore, marketable bulb yield exhibited extremely significant positive correlations with dry matter translocation before the onset of bulbing and dry matter accumulation following bulbing initiation. It was concluded that the appropriate fertilizer application (F2), characterized by a fertilization rate of 339-216-318 kg ha⁻¹ for N-P₂O₅-K₂O, enhanced onion bulb yield and nitrogen fertilizer productivity by promoting post-bulbing dry matter accumulation. This study emphasizes the significance of optimizing the fertilization rate as a crucial factor in achieving high-yield and highly efficient onion cultivation by enhancing dry matter accumulation. Full article

The purpose of this study was to determine the impact of blanching various onion (Allium cepa L.) varieties on the process of lactic fermentation by probiotic strain Levilactobacillus brevis ŁOCK 0944. The materials for the research were twelve varieties of yellow onion: Venecia, Moondance, Sedona, Alonso, Hysky, Centro, Dormo, Hypark, Hybelle, Armstrong, EXP 2236, and Hysinger. We also studied the resulting changes in bioactive compound content. Acidic bacterial metabolites, the lactic acid bacteria count, and the polyphenol and carbohydrate contents were assessed in both raw onions and onions blanched at 60 °C, before and after fermentation. Onion varieties that showed morphological changes after blanching (Hysky, Centro, Dormo) demonstrated better growth of L. brevis and higher lactic acid production. Blanching loosened the tissue structure, reducing the carbohydrate content in the blanched and fermented onions, particularly Alonso, Centro, Dormo, and Hypark varieties. Although the combined process reduced the polyphenol content, four varieties showed no statistically significant differences, indicating variety-specific responses. The varying susceptibility of onion varieties to thermal treatment highlights the importance of selecting the appropriate variety for further processing. Full article

Salinity poses a significant challenge in modern agriculture, often inhibiting growth and yield, especially in sensitive crops like onions (Allium cepa L.). This study evaluated the effectiveness of a freshwater-algae-based biostimulant on two onion cultivars, Franciscana IPA-10 and Vale Ouro IPA-11, to mitigate saline irrigation’s adverse effects. Five biostimulant concentrations (0, 1, 2, 3, and 4 mL L⁻¹, applied to the soil) were tested, along with two foliar treatments at 2 mL L⁻¹ as controls. Our findings showed that applying 4 mL L⁻¹ to the soil boosted growth rates to 1.0 cm per day (1), increased the potassium-to-sodium ratio in bulbs, and improved both average bulb weight by 25.11% and overall productivity by 24.28%, relative to untreated conditions. These results suggest that the biostimulant at 4 mL L⁻¹ is an effective method to enhance resilience to saline stress and increase productivity in the IPA-10 and IPA-11 cultivars. However, while the biostimulant improved plant performance, it did not counteract the accumulation of salts in the soil. Therefore, additional management practices such as leaching and drainage are recommended to ensure sustainable onion production under saline water irrigation. Full article

Scallions are a highly valued leafy vegetable and are enjoyed worldwide due to their appealing taste and nutritional benefits. A combination of short cultivation cycles and high market demand not only enhances food security but also offers a profitable opportunity for growers. In our study, we aim to evaluate the effect of increasing boron (B) applications, specifically 0, 0.2, 0.4, 0.8, 1.2, and 1.6 mM B supplied as boric acid (H₃BO₃) in the nutrient solution, on several key physiological and agronomic parameters in scallions. Results showed that the effects of increasing B levels on biomass production were insignificant, but the root fresh weight (FW) significantly decreased with all B levels. Higher B levels (1.2 and 1.6 mM) caused decreases of 22.9% and 29.6%, respectively. The effects of all B levels on photosynthetic pigment contents [chlorophyll (Chl) a, b, a + b, and carotenoid (Car)], root and shoot membrane permeability (MP), and root, shoot, and leaf nutritional status [phosphorus (P), potassium (K), calcium (Ca), and sodium (Na) concentrations] were found insignificantly. However, all B levels caused a significant increase in the B concentrations of the root, shoot, and leaf of scallions and plants translocated the majority of applied B into their leaves. The translocation factor (TF) of B from the root to the leaf was found to be 138.2%, 133.3%, and 107.3% with 0.8, 1.2, and 1.6 mM B levels, respectively. Moreover, plants exposed to high levels of B showed no significant response or toxicity symptoms. We concluded that B is a phloem mobile element in onion, a non-graminaceous monocotyledonous plant, and therefore accumulates in the upper organs but illustrates partial toxicity symptoms in leaves. Studies with higher B concentrations could be recommended to determine critical B levels for green onion production in B-contaminated areas. Full article

Onions (Allium cepa L.) are widely consumed worldwide and are recognized for their high content of bioactive compounds with potential health benefits. This study investigates the nutritional and phytochemical properties of three onion varieties—Tropea red onion, red onion, and yellow onion—analyzed in their whole form as well as in their peel and pulp. An innovative drying system was employed to assess its impact on the retention of bioactive compounds. The results highlight significant differences in nutrient composition among varieties and onion parts. The peel exhibited the highest concentrations of proteins, phenolic compounds, flavonoids, and antioxidants, followed by the whole onion and pulp. Tropea red onion stood out for its superior antioxidant capacity, vitamin C content, and phenolic acid levels, reinforcing its potential for functional food applications. This study also revealed that mineral content, particularly calcium, potassium, and sulfates, varied across onion varieties, influencing their nutritional and health-promoting properties. These findings support the valorization of onion byproducts for their bioactive potential and sustainability in the food industry. The data emphasize the need for further research on innovative processing techniques that enhance the bioavailability and effectiveness of onion-derived health-promoting compounds. Full article

Considering the resistance of weeds to different herbicides with different mechanisms of action, the search for new, more selective compounds with low toxicity to other species in nature has been very important for the development of agriculture. Because of that, considering the biological activity of allelochemicals and natural epoxides, four new epoxy compounds derived from dehydrocostus lactone were synthetized and evaluated for their potential herbicide activity against three species of seeds, Allium cepa (onion), Lepidium sativum (garden cress), and Lactuca sativa (lettuce). In assays with A. cepa, compound 4 inhibited radicle length by 80% at 100 μM. Notably, for L. sativum, compound 4 showed significant inhibition, reducing stalk and radicle lengths by 80% at 100 μM, surpassing the performance of the commercial herbicide Logran. However, diol 5 notably inhibited radicle growth by 28% at 100 μM, making the most significant observed effect. One of the noteworthy lactones studied is epoxide 4. This highlights the importance of the epoxide functional group in affecting both radicle and shoot lengths of seeds. Therefore, the synthesis of these compounds has proven advantageous and holds great potential for the development of new herbicides. Full article

The efficiency and consistency of biologicals in the field remain a drawback of current conventional products. The development of systemic biological products has opened a new avenue for microbiological and agricultural research. In this study, we evaluated over a two-year period (2022 and 2023) the functioning of two systemic products, a biofertilizer and biofungicide, on the performance of the onion. The first indicator of proper functioning of these products in onions was reflected in increased chlorophyll accumulation. At the end of both years, the inoculated plants were taller, heavier, and developed more leaves than their control counterparts (p < 0.5). Inoculated onion bulbs collected at harvest time were significantly heavier (45.1% in 2022 and 56.2% in 2023) than their non-inoculated counterparts (p < 0.5). Onion quality, expressed in terms of total soluble solids and pyruvic acid content, was also significantly improved in plants inoculated with the biological products; the two-year average values for these quality variables were 10.2 vs. 14.4°Brix and 2.3 vs. 4.0 µmol∙g⁻¹ for control and biologically treated plants, respectively. The two-year average fungal incidence was 1.9 times greater in the control group than in the inoculated plants, while the average onion yield for this period was 44.7% higher (p < 0.5) in the biologically treated plot (54.7 t∙ha⁻¹) than in the control one (37.8 t∙ha⁻¹). Based on comparisons with previous studies employing conventional biologicals, our results demonstrate the superior effectiveness of the systemic biologicas in improving onion performance. Full article

The plant cell wall (CW) is a physical barrier that plays a dual role in plant physiology, providing structural support for growth and development. Understanding the dynamics of CW growth is crucial for optimizing crop yields. In this study, we employed onion (Allium cepa L.) epidermis as a model system, leveraging its layered organization to investigate growth stages. Microscopic analysis revealed proportional variations in cell size in different epidermal layers, offering insights into growth dynamics and CW structural adaptations. Fourier transform infrared spectroscopy (FTIR) identified 11 distinct spectral intervals associated with CW components, highlighting structural modifications that influence wall elasticity and rigidity. Biochemical assays across developmental layers demonstrated variations in cellulose, soluble sugars, and antioxidant content, reflecting biochemical shifts during growth. The differential expression of ten cell wall enzyme (CWE) genes, analyzed via RT-qPCR, revealed significant correlations between gene expression patterns and CW composition changes across developmental layers. Notably, the gene expression levels of the pectin methylesterase and fucosidase enzymes were associated with the contents in cellulose, soluble sugar, and antioxidants. To complement these findings, machine learning models, including Support Vector Machines (SVM), k-Nearest Neighbors (kNN), and Neural Networks, were employed to integrate FTIR data, biochemical parameters, and CWE gene expression profiles. Our models achieved high accuracy in predicting growth stages. This underscores the intricate interplay among CW composition, CW enzymatic activity, and growth dynamics, providing a predictive framework with applications in enhancing crop productivity and sustainability. Full article

Onion (Allium cepa L.) plants produce umbellate inflorescences that bear dozens of hermaphrodite flowers. Outcrossing is encouraged by a strong protandrous dichogamy. Honeybees are reported as the most suitable pollinator for this crop due to their efficiency in pollen transfer. However, bee activity does not always guarantee pollination success and an adequate seed set. This work aimed to analyze the developmental changes of the pistil along the flower lifespan to determine the reasons for common failures in the onion seed set. Studies were carried out in two productive seasons, in a male sterile line and a fertile line, using two different pollination procedures. The results showed that the stigma papillae did not fully develop until 4 days after anthesis (DAA), reducing the stigma receptivity to only 4 days. The style did not reach its maximum length until 8 DAA, when ovule fertility was achieved. Eight days were needed for the pollen tube to grow, reach, and fertilize the ovules. The results were consistent over two consecutive years. The short period of stigmatic receptivity and strong protandrous dichogamy limit the duration of the effective pollination period and could explain the poor cropping performance in obtaining seeds from some onion hybrid lines. Full article

Soil contamination by petroleum derivatives is a growing environmental issue that affects ecosystems and human health, since the hydrocarbons present in them are persistent and toxic, compromising soil quality and biodiversity. This study investigated the potential of a biosurfactant from Candida bombicola URM 3718, to be applied to remove oils from contaminated soils. After isolation, its main surface-active characteristics were evaluated. The biomolecule was then characterized by NMR and FTIR spectroscopy analyses, and its ability to remove motor oil adsorbed on soils with different particle sizes and its genotoxicity profile were determined. Tests to determine surfactant activities revealed a reduction in water surface tension to 30 mN/m with a critical micelle concentration (CMC) of 0.03 g/L. The surfactant was shown to have a glycolipid nature. The removal of burned engine oil sorbed on various kinds of soil was investigated in both static and kinetic assays using the biosurfactant at different concentrations, namely, ½ CMC (0.015 g/L), CMC (0.03 g/L), and 2 × CMC (0.06 g/L). In the static tests, the maximum removal percentage was 65.32% for burned engine oil adsorbed on sandy soil, 59.04% on silty soil, and 57.42% on clayey soil, while in the kinetic tests, this parameter reached 98.60%, 93.22%, and 92.55% for sandy, silty, and clayey soils, respectively. The genotoxicity profile evaluated in Allium cepa roots did not reveal necrosis or the occurrence of micronuclei in the plant root cap cells, demonstrating that the biomolecule thus produced is not toxic. Such findings, when taken together, indicate that the C. bombicola URM 3718 biosurfactant was effective in removing oils and could, therefore, be used as an alternative agent for remediating hydrocarbon-polluted soil. Full article

The role of onion as the second most-consumed and cultivated vegetable around the world and its renowned qualities that lead it to be called the “queen of the kitchen” have positioned it as a vital source of nutritional and economic contributions around the world. Polyploidy serves as a groundbreaking innovation in plant breeding, improving the yield and vigor of plants. This study was conducted to determine the effects of applying different concentrations of colchicine to onion seedlings on their morphology, antioxidant activity, and dissolved sugars. The mutagen was applied to the onion seeds at three different concentrations (0.05, 0.1, and 0.2% w/v) for an exposure period of 24 h. A chromosomal analysis confirmed the induction of polyploidy, which led to the successful duplication of the chromosome number from diploid (2n = 16) to tetraploid (4n = 32). The control recorded a survival rate of 91.57%, while 83.33%, 3.33%, and 0.00% survival rates were recorded for seedlings treated with 0.05%, 0.1%, and 0.2% (w/v) concentrations of colchicine, respectively. Furthermore, the tetraploids showed significant differences in morphology, producing the tallest seedlings (reaching up to 73.6 cm tall) and the greatest average bulb diameter (of 5.64 cm) after 14 weeks. The tetraploids also showed significant differences in antioxidant activity and the amount of dissolved sugars, recording the highest DPPH scavenging percentage of 72.58% and refractive index of 1.369. Successful induction of polyploidy was achieved with the application of 0.05% (w/v) colchicine, which produced tetraploids that are morphologically and biochemically superior to other treated and control plants at a significance level of p < 0.05. Full article

In this study, polyphenols in the crude extract (CE) from red onion peel were recovered by macroporous resin, and their antioxidant and anti-inflammatory activities were evaluated. Among the four resins screened (SP850, XAD2, XAD7HP, and XAD16N), XAD7HP showed the highest desorption and recovery ratios, and it was used to optimize polyphenol recovery through single-factor experiments. The optimal conditions were established as 1 g resin, pH 4, 25 °C, 7 h for adsorption, followed by desorption with 70% ethanol for 1 h at 25 °C. These conditions achieved 85.00% adsorption ratio, 87.10% desorption ratio, and 20.9% yield of the macroporous resin-recovered extract (MRE) from the CE. HPLC analysis revealed that rosmarinic acid, quercetin, and myricetin were major compounds in the MRE, with the content of these compounds higher (about 7-fold) compared to the CE, confirming enhanced recovery of polyphenols by macroporous resin. Moreover, FT-IR and ¹H-NMR analysis confirmed the successful recovery of these polyphenol compounds in the MRE. Furthermore, the MRE displayed significantly improved antioxidant activities (DPPH, ABTS, and FRAP) and anti-inflammatory activities (inhibition of nitric oxide synthesis and reactive oxygen species production) compared to the CE. In summary, our findings suggest that macroporous resin can effectively recover polyphenol compounds from red onion peel extract and enhance their biological activities. Full article

The yield of flowering crops depends on multiple factors, with pollination and the availability of nutrients being particularly crucial. However, fewer studies have explored the combined effects of nutrients and insect-mediated pollination on onions (Allium cepa L.). Here, we studied how different levels of insect pollination (0%, 25%, 50%, and 100%) and nitrophos fertilizer application (188, 375, and 750 kg/hectare) affect onion seed yield. We found that pollination benefits to yield were maximum at intermediate levels of nitrophos availability. A higher pollinator abundance was recorded at a high nitrophos level, followed by intermediate and low levels. Syrphid flies and honey bees were the most abundant insect pollinators. The abundance of honey bees was higher at a low nitrophos level, while syrphid flies were more abundant at a higher nitrophos level. Moreover, the umbel weight and seed number were higher at the intermediate fertilizer level. Also, single visits by insect pollinators were observed, and the highest umbel weight was found at the intermediate fertilizer level with a single visit from A. florea. This finding provides evidence that resource and pollination availability have interactive, nonlinear effects on seed production. Our results also support ecological intensification as a reliable strategy for sustainable agro-ecosystem management. Full article

Horticulture is mainly based on transplanting seedlings produced by specialized nurseries. The recent European authorization of frass in organic farming presents new opportunities for the development of organic seedling production. Frass, a by-product of insect farming, offers innovative solutions for this sector. It mainly consists of insect excrement, exuviae, and uningested feed. Their fertilizing and biostimulating effects have been demonstrated in various pot and field crops experiments. However, the current knowledge regarding the application of frass in seedling production remains insufficient. This study aims to assess the optimal dose of mealworm frass in germination substrates for Allium cepa L., Beta vulgaris L., and Brassica rapa L. Germination and phytotoxicity tests were carried out, with seedlings evaluated one month after sowing in substrates containing frass at concentrations of 0.5%, 1%, 2%, and 3% of frass. The germination test revealed that the dilution of the frass at 1:100 produced a phytostimulant effect on A. cepa and a moderate phytotoxic effect on B. vulgaris and B. rapa. The application of mealworm frass at a concentration of 0.5–1% was generally the most effective dose, although all doses of frass in the substrate resulted in seedlings whose root length, leaf length, number of leaves, and biomass were significantly higher than the control. In conclusion, the application of low doses of mealworm frass in organic seedling production is promising and allows the management of potential phytotoxicity. Full article