Search Results (179)

Pak choi (Brassica chinensis L.) has a strong adsorption capacity for the heavy metal cadmium (Cd), which is a big threat to human health. Traditional detection methods have drawbacks such as destructiveness, time-consuming processes, and low efficiency. Therefore, this study aimed to construct a non-destructive prediction model for Cd content in pak choi leaves using hyperspectral technology combined with feature selection algorithms and multivariate regression models. Four different cadmium concentration treatments (0 (CK), 25, 50, and 100 mg/L) were established to monitor the apparent characteristics, chlorophyll content, cadmium content, chlorophyll fluorescence parameters, and spectral features of pak choi. Competitive adaptive reweighted sampling (CARS), the successive projections algorithm (SPA), and random frog (RF) were used for feature wavelength selection. Partial least squares regression (PLSR), random forest regression (RFR), the Elman neural network, and bidirectional long short-term memory (BiLSTM) models were established using both full spectra and feature wavelengths. The results showed that high-concentration Cd (100 mg/L) significantly inhibited pak choi growth, leaf Cd content was significantly higher than that in the control group, chlorophyll content decreased by 16.6%, and damage to the PSII reaction centre was aggravated. Among the models, the FD–RF–BiLSTM model demonstrated the best prediction performance, with a determination coefficient of the prediction set (Rp²) of 0.913 and a root mean square error of the prediction set (RMSEP) of 0.032. This study revealed the physiological, ecological, and spectral response characteristics of pak choi under Cd stress. It is feasible to detect leaf Cd content in pak choi using hyperspectral imaging technology, and non-destructive, high-precision detection was achieved by combining chemometric methods. This provides an efficient technical means for the rapid screening of Cd pollution in vegetables and holds important practical significance for ensuring the quality and safety of agricultural products. Full article

This study evaluated the growth performance and physiological responses of 24 Korean landrace accessions of pak choi (Brassica rapa subsp. chinensis) under polyethylene glycol (PEG)-induced drought stress to identify indicators for selecting drought-resistance genotypes. Electrolyte leakage (EL) and chlorophyll fluorescence (Fv/Fm) analyses showed that resistance accessions (IT262109(11), IT279432(12), IT293143(20)) had minimal increases in EL and maintained high Fv/Fm values under stress, indicating superior membrane stability and photosystem II activity. In contrast, sensitive accessions exhibited a sharp rise in EL and a decline in Fv/Fm to approximately 0.3 under 25% PEG treatment, reflecting severe physiological damage. Principal component analysis (PCA) biplot based on integrated growth and photosynthetic parameters differentiated resistance and sensitive groups, with PC1 representing photosynthetic efficiency versus membrane injury. Growth trait responses interaction analysis using GGE biplot of six representative accessions (three resistance, three sensitive) demonstrated that resistance genotypes had smaller positional shifts across treatments, indicating greater growth stability, while sensitive genotypes showed pronounced variability and environment-specific responses. This study provides a framework integrating growth and physiological indicators for identifying drought-resistance pak choi accessions, offering valuable implications for breeding programs aimed at climate-resilient cultivar development. Full article

Black soil, as a vital environment for food production, is currently facing severe degradation. Earthworm tillage is recognized as an effective approach to improving black soil structure; however, its optimal implementation strategy remains unclear. In this study, a pot experiment using Pak Choi (Brassica rapa L. ssp. chinensis) was conducted under an orthogonal design with three factors—earthworm size, application timing, and quantity. Combined with yield measurement, analysis of variance (ANOVA), and grey relational analysis (GRA), the effects of earthworm application on plant growth and soil structure were systematically evaluated. In addition, Computer Tomography (CT) scanning and three-dimensional reconstruction were employed to visualize the pore structures of representative soil samples. The results showed that large earthworms significantly enhanced both leaf and root biomass of Pak Choi, exhibiting a stronger promoting effect than small earthworms. Application at the sowing stage resulted in the greatest yield improvement, whereas applications at other growth stages had limited effects. The number of earthworms did not show a statistically significant impact under the experimental conditions, and its potential influence requires further verification under more refined density gradients. Overall, this study elucidates the mechanisms by which earthworm tillage improves soil structure and promotes crop growth, providing a theoretical basis for the restoration and sustainable utilization of degraded black soil. Full article

Environmental factors like light, photoperiod, temperature, and water are vital for crop growth, and even slight deviations from their optimal ranges can cause seedling stress and reduce yield. Therefore, this study aimed to quantify seedling stress symptoms using image features analysis under varying light, photoperiod, temperature, and water conditions. Seedlings were grown under controlled low, normal, and high environmental conditions. Light intensity at 50 µmol m⁻² s⁻¹ (low), 250 µmol m⁻² s⁻¹ (normal), and 450 µmol m⁻² s⁻¹ (high), photoperiod cycles, 8/16 h (day/night) (low), 10/14 h (day/night) (normal), and 16/8 h (day/night) (high) day/night, temperature at 20 °C (low), 25 °C (normal), and 30 °C (high), and water availability at 1 L per day (optimal), 1 L every two days (moderate stress), and 1 L every three days (severe stress) were applied for 15 days. Commercial low-cost RGB, thermal, and depth sensors were used to collect data every day. A total of 1080 RGB images, which were pre-processed with histogram equalization and filters (Median and Gaussian), were used for noise reduction to minimize illumination effects. Morphological, color, and texture features were then analyzed using ANOVA (p < 0.05) to assess treatment effects. The result shows that the maximum canopy area for tomato was 115,226 pixels, while lettuce’s maximum plant height was 9.28 cm. However, 450 µmol m⁻² s⁻¹ light intensity caused increased surface roughness, indicating stress-induced morphological alteration. The analysis of Combined Stress Index (CSI) values indicated that the highest stress levels were 50% for pepper, 55% for tomato, 62% for cucumber, 55% for watermelon, 50% for lettuce, and 50% for pak choi. The findings showed that image-based stress detection enables precise environmental control and improves early-stage crop management. Full article

Lettuce (Lactuca sativa), pak choi (Brassica rapa), and basil (Ocimum basilicum) were grown in hydroponic NFT systems under four nitrate levels (80–180 mg L⁻¹ N). We measured natural microbial contamination by plating nutrient-solution samples and leaf washes to obtain colony-forming unit (CFU) counts of bacteria and fungi. Separately, postharvest leaves were artificially inoculated with Botrytis cinerea and stored at 22 °C or 4 °C for 7 days to assess gray mold. In lettuce, high N (180 mg L⁻¹) markedly increased culturable microbial loads in both solution and leaves, whereas pak choi microbial counts remained low at all N levels. Basil showed a non-linear response: CFU counts peaked at moderate N (120 mg L⁻¹) and were lower at both deficit and excess N. At 22 °C, gray mold severity in pak choi increased with N; leaves fertilized at N150–180 suffered about 1.5–2 times greater lesion area than those at N80. By contrast, lettuce exhibited the worst decay under N deficiency: N80 leaves developed the largest lesions by 4–7 DPI, while moderate N (120–150 mg L⁻¹) minimized disease progression. Basil was highly susceptible under warm storage: all N levels reached near-total decay by 7 days, though N120 delayed early infection slightly. Refrigeration (4 °C) greatly suppressed lesion development in lettuce and pak choi, although high-N pak choi still showed ~20–30% more infected area than low-N after 7 days. Basil, however, suffered chilling injury at 4 °C, and all refrigerated basil leaves decayed severely (regardless of N). These results indicate crop-specific nutrient and storage strategies: avoid excessive N in pak choi, maintain balanced N in lettuce, and handle basil with non-chilling methods to reduce postharvest gray mold. Full article

The application of livestock manure can introduce antibiotic-resistant bacteria (ARB) into soil–vegetable systems, potentially shaping the antibiotic resistance profiles of plants. This study investigated the effects of manure containing chlortetracycline (CTC) on antibiotic resistance in pakchoi grown in three distinct soil types (black soil, fluvo-aquic soil, and red soil). The results demonstrated that CTC-manure application significantly increased the relative abundance of CTC-resistant endophytic bacteria (CREB), with the magnitude of the increase following the order: black soil (235.43%) > fluvo-aquic soil (64.5%) > red soil (10.68%). Furthermore, the presence of CTC promoted the proliferation of Acinetobacter and increased the abundance of potential pathogens (such as Klebsiella, Rhodococcus, and Corynebacterium), thereby elevating the risk of antibiotic resistance transmission. Metabolomic analysis revealed that CTC induced the most substantial metabolic alterations in pakchoi grown in red soil. Correlation analysis indicated that the CREB community structure was primarily shaped by soil properties, including total nitrogen, total phosphorus, and organic matter, and was significantly correlated with indigenous soil ARB (Pseudomonas, Bacillus, and Stenotrophomonas). This study elucidates the mechanisms underlying manure-driven antibiotic resistance dissemination in vegetable production systems and offers a theoretical foundation for developing agricultural practices to mitigate associated risks. Full article

Backgrounds: purple pakchoi (Brassica rapa subsp. chinensis (L.) Hanelt) is rich in anthocyanins, which contribute to its significant edible, ornamental, and potential health-promoting value. Fine mapping of the genes responsible for the purple-leaf trait is essential for establishing molecular marker-assisted breeding and facilitating genetic improvement. Methods: In this study, we used the inbred purple-leaf line ‘PQC’ and green-leaf line ‘HYYTC’ as parents to construct a six-generation genetic segregation population. We analyzed the inheritance pattern of the purple-leaf trait and combined Bulked Segregant Analysis Sequencing (BSA-Seq) with penta-primer amplification refractory mutation system (PARMS) to map the causal gene. Results: the main findings are as follows: the purple-leaf trait is controlled by a single dominant gene. Using BSA-Seq and PARMS, the genes were mapped to a 470 kb region (31.18–31.65 Mb) on chromosome A03. Within this interval, 29 candidate genes were identified, Bra017888 which encoding trehalose phosphate synthase 10 (TPS10), was highlighted as a potential regulator of anthocyanin biosynthesis. A developed molecular marker, SNP31304070, based on the final candidate region, successfully distinguished between purple homozygous and purple heterozygous plants in the F₂ and F₃ populations. Conclusions: the candidate gene controlling purple-leaf trait was finally located to A03 chromosome 31.18–31.65 Mb. The SNP31304070 marker and trait were co-separated, This marker could be applied to molecular-assisted breeding in purple pakchoi. Full article

Lead (Pb) in soil poses serious environmental and health risks, and its removal requires complex and costly treatment methods to meet strict regulatory standards. To effectively address this challenge, innovative and efficient techniques are essential. Sepiolite-supported MnFe₂O₄ (MnFe₂O₄/SEP) composites were synthesized via a chemical co-precipitation method. The effects of MnFe₂O₄/SEP on soil pH, cation exchange capacity (CEC), available Pb content, Pb²⁺ uptake, and the activities of antioxidant enzymes in Brassica chinensis (Pak Choi) were examined. MnFe₂O₄/SEP showed superior Pb²⁺ adsorption compared to SEP alone, fitting Langmuir models, Dubinin-Radushkevich (D-R) models, Temkin models and pseudo-second-order kinetics. The maximum adsorption capacities at 298, 308, and 318 K were 459, 500 and 549 mg·g⁻¹, respectively. XPS analysis indicated that chemisorption achieved through ion exchange between Pb²⁺ and H⁺ was the main mechanism. MnFe₂O₄/SEP increased the soil pH by 0.2–1.5 units and CEC by 18–47%, while reducing available Pb by 12–83%. After treatment with MnFe₂O₄/SEP, acid-extractable and reducible Pb in the soil decreased by 14% and 39%, while oxidizable and residual Pb increased by 26% and 21%, respectively. In Brassica chinensis, MnFe₂O₄/SEP reduced Pb²⁺ uptake by 76%, increased chlorophyll content by 36%, and decreased malondialdehyde (MDA) levels by 36%. The activities of antioxidant enzymes—superoxide dismutase (SOD), peroxidase (POD), and catalase (CAT)—were decreased by 29%, 38% and 17%, respectively. These findings demonstrate that MnFe₂O₄/SEP is an efficient Pb²⁺ adsorbent that immobilizes Pb in soil mainly through ion exchange, thereby providing a highly effective strategy for remediating Pb-contaminated soils and improving plant health. Full article

The fate and risk identification of cyantraniliprole (CYA) and lufenuron (LUF) in pak choi were systematically analyzed through an investigation comprising field trials, dissipation kinetics, and dietary risk assessment. Initially, field experiments across ten Chinese provinces revealed half-lives of 3.04–5.41 d for CYA and 2.02–5.13 d for LUF, with dissipation following single first-order (SFO) kinetics or double first-order in parallel (DFOP) kinetics. Terminal residues (<limit of quantification (LOQ) to 0.29 mg/kg) were below maximum residue limits. Dissipation rates were significantly influenced by temperature, climate, and crop growth stage. Additionally, the multidimensional dietary assessment using deterministic and probabilistic models revealed acceptable long-term risk levels for CYA and LUF among consumer groups (risk quotients < 28.4%). Overall, this first comprehensive study from cultivation to consumption provides crucial insights for rational pesticide use in pak choi. Full article

Developing environmentally friendly and cost-effective substrates is critical to enhance resource efficiency and productivity in plant factories with artificial lighting (PFALs). This study employed a molded coconut coir substrate (coconut coir composited with polyurethane hydrophilic adhesive, MCCS) in PFALs to cultivate lettuce (Lactuca sativa L.) and pak choi (Brassica rapa ssp. chinensis). During the transplanting stage, the roots exposed outside the MCCS of lettuce and pak choi were 13.40% and 19.92% shorter, respectively, than in the sponge treatment, and more amenable to mechanical transplanting. This compensated for the neglect of operational efficiency in traditional lifecycle assessment (LCA). Furthermore, compared with sponge and rockwool, MCCS significantly enhanced the yield of lettuce and pak choi by up to 27.33% and 67.19%, respectively. Meanwhile, MCCS significantly increased the chlorophyll content of lettuce compared to sponge by 8.56%. Compared with rockwool, MCCS significantly increased the chlorophyll b content (7.36%), antioxidant content, and antioxidant activity (total phenolics by 13.59%, total flavonoid by 18.43%, FRAP by 12.96%, and DPPH by 19.87%) of lettuce. For pak choi, MCCS increased the soluble protein content in the blade and total phenolics content in the petiole by 32.01% and 14.76%, respectively. More importantly, the use of MCCS led to a significant reduction in the energy consumption per unit area yield of lettuce and pak choi, with maximum reductions of 22.98% and 40.91%, respectively. This eco-friendly substrate is suitable for replacing sponge and rockwool in the production of lettuce and pak choi in PFALs. Full article

Organophosphate pesticides, fungicides, and neonicotinoid insecticides are frequently employed in the cultivation and production of leafy vegetables. The conventional detection methods for these pesticides rely on chromatographic techniques, which are characterized by good precision and sensitivity. Nevertheless, these methods suffer from drawbacks such as complex sample pretreatment, prolonged detection times, and high costs, hindering the realization of on-site detection. This paper introduces a detection method based on surface-enhanced Raman spectroscopy (SERS) for the quantitative and qualitative analysis of pesticide residues in leafy vegetables. Gold nanoparticles (AuNPs) were meticulously synthesized to serve as the substrate for enhancing Raman signals. The average particle size was approximately 50 nm, and a significant absorption peak appeared at 536 nm. The density functional theory (DFT) with the B3LYP/6-311G was utilized to calculate the theoretical Raman spectra of the pesticides. The characteristic Raman peaks of the pesticides were selected as calibration peaks to establish calibration equations relating the concentration of pesticide residues to the intensity of these calibration peaks. By substituting the intensity of the calibration peak corresponding to the lowest detectable limit in the SERS spectra into the calibration equation, the quantitative detection limit was calculated. The study revealed that the detection limit for phosmet residues in Chinese cabbage could be was below 0.5 mg/kg, with an R² of 0.93363, a standard deviation ranging from 3.87% to 8.56%, and recovery rates between 94.67% and 112.89%. For thiabendazole residues in water spinach, the detection limit could be below 1 mg/kg, with an R² of 0.98291, a standard deviation of between 1.71% and 9.29%, and recovery rates ranging from 87.67% to 107.83%. In the case of acetamiprid residues in pakchoi, the detection limit could also be below 1 mg/kg, with an R² of 0.95332, a standard deviation of between 4.00% and 9.10%, and recovery rates ranging from 90.67% to 113.75%. These findings demonstrate that the SERS-based detection method for the semi-quantitative and qualitative analysis of pesticide residues in leafy vegetables is an effective approach, enabling rapid and reliable detection of pesticide residues in leafy vegetables. Full article

The high pH and heavy metal leaching of argon oxygen decarburization (AOD) slag limit its application in agriculture. Slag carbonation can aid in decreasing slag alkalinity and inhibit heavy metal release; the environmental safety of utilizing carbonated AOD slag (CAS) as a fertilizer remains a topic of significant debate, however. In this work, pakchoi (Brassica chinensis L.) was planted in CAS-fertilized soil to investigate the accumulation and migration behavior of heavy metals in the soil–plant system and perform an associated risk assessment. Our results demonstrated that CAS addition increases Ca, Si, and Cr concentrations but decreases Mg and Fe concentrations in soil leachates. Low rates (0.25–1%) of CAS fertilization facilitate the growth of pakchoi, resulting in the absence of soil contamination and posing no threat to human health. At the optimal slag addition rate of 0.25%, the pakchoi leaf biomass, stem biomass, leaf area, and seedling height increased by 34.2%, 17.2%, 26.3%, and 8.7%, respectively. The accumulation of heavy metals results in diverging characteristics in pakchoi. Cr primarily accumulates in the roots; in comparison, Pb, Cd, Ni, and Hg preferentially accumulate in the leaves. The migration rate of the investigated heavy metals from the soil to pakchoi follows the order of Cr > Cd > Hg > Ni > Pb; in comparison, that from the roots to the leaves follows the order Cd > Ni > Hg > Cr > Pb. Appropriate utilization of CAS as a mineral fertilizer can aid in improving pakchoi yield, achieving sustainable economic benefits, and preventing environmental pollution. Full article

This study investigates growth responses, heavy metal (Cd, As) uptake, translocation, and mineral nutrient regulation in leafy vegetables with varying heavy metal tolerance, addressing the threat posed by combined Cd and As pollution. Three high-tolerance, four moderate-tolerance, and one sensitive leafy vegetable were grown in Cd+As-contaminated hydroponics. Post-harvest yields and concentrations of Cd, As, and trace elements were assessed. Results showed that (1) compared with single heavy metal treatments, the combination of Cd and As significantly increased the translocation factor of Cd in black bean sprouts and white radish sprouts by up to 83.83% and 503.2%; (2) changes in mineral nutrient concentrations in leafy vegetables were similar between single and combined heavy metal stresses, but the regulatory patterns varied among different leafy vegetable species; (3) under Cd/As exposure, high-tolerance leafy vegetables (e.g., pak choi) had strong heavy metal accumulation abilities, and heavy metal stress positively regulated mineral elements in their roots; In contrast, sensitive leafy vegetables (e.g., pea sprouts) often exhibited suppressed mineral element content in their roots, which was a result of their strategy to reduce heavy metal uptake. These results offer key insights into resistance mechanisms against combined heavy metal pollution in leafy vegetables, supporting phytoremediation efforts and safe production. Full article

Microgreens, having short growth cycles and efficient nutrient uptake, are ideal candidates for biofortification. This study investigated the effects of selenium (Se) and zinc (Zn) on photosynthetic performance in four hydroponically grown Brassica microgreens (broccoli, pak choi, kohlrabi, and kale), using direct and modulated chlorophyll a fluorescence and chlorophyll-to-carotenoid ratios (Chl/Car). The plants were treated with Na₂SeO₄ at 0 (control), 2, 5, and 10 mg/L or ZnSO₄ × 7H₂O at 0 (control), 5, 10, and 20 mg/L. The results showed species-specific responses with Se or Zn uptake. Selenium enhanced photosynthetic efficiency in a dose-dependent manner for most species (8–26% on average compared to controls). It increased the plant performance index (PI_tot), particularly in pak choi (+62%), by improving both primary photochemistry and inter-photosystem energy transfer. Kale and kohlrabi exhibited high PSII-PSI connectivity for efficient energy distribution, with increased cyclic electron flow around PSI and reduced Chl/Car up to 8.5%, while broccoli was the least responsive. Zinc induced variable responses, reducing PI_tot at lower doses (19–23% average decline), with partial recovery at 20 mg/L (9% average reduction). Broccoli exhibited higher susceptibility, with inhibited Q_A re-oxidation, low electron turnover due to donor-side restrictions, and increased pigment ratio (+3.6%). Kohlrabi and pak choi tolerated moderate Zn levels by redirecting electron flow, but higher Zn levels impaired PSII and PSI function. Kale showed the highest tolerance, maintaining stable photochemical parameters and total electron flow, with increased pigment ratio (+4.5%) indicating better acclimation. These results highlight the beneficial stimulant role of Se and the dual essential/toxic nature of Zn, thus emphasizing genotype and dose-specific optimizations for effective biofortification. Full article

Hydroponics is currently one of the primary methods for soilless cultivation. Although the phenotype and quality of vegetables differ between hydroponic and soil-based systems, limited research has been conducted on the selection and breeding of pakchoi cultivars specifically suited for hydroponics. In this study, principal component analysis (PCA) and cluster analysis were performed on the commercial traits, agronomic characteristics, and nutritional quality of 20 pakchoi parental lines grown under hydroponic conditions to classify and screen suitable germplasm for breeding. PCA reduced the 11 agronomic traits into two independent principal components, accounting for a cumulative contribution of 79.22%. Cluster analysis grouped the 20 parental lines into four categories based on the composite scores of agronomic traits and nutritional quality. Group 3 was selected for breeding programs aiming to develop high-yielding cultivars with a desirable morphology. For breeding targets emphasizing darker leaves and petiole coloration, Group 4 presented the most suitable germplasm. Group 1 was ideal for enhancing nutritional quality by offering parent lines rich in calcium, magnesium, vitamin C, and amino acids. Alternatively, Group 2 contained lines with high levels of soluble proteins, amino acids, and soluble sugars. Full article