Brassica Chinensis Research Articles

Methylcyclopropene treatment retards the yellowing in pak choi (Brassica rapa subsp. Chinensis) through modulating the programmed cell death during storage at 20°C

The deterioration of post-harvest quality in plants has been shown to be connected with the occurrence of programmed cell death (PCD). Our previous research indicated that 5 μL L−1 1-Methylcyclopropene (1-MCP) delays the yellowing of post-harvest pak choi leaves. However, whether 1-MCP alleviates pak choi yellowing through regulating PCD process, and the regulatory mechanism of 1-MCP on PCD are still unclear. Results showed that 5 μL L−1 1-MCP could retard the PCD process of pak choi as proved by the maintenance of lower cytochrome C content and caspase-3 activity. The results of cell mortality and trypan blue staining further confirmed this view. Forty-five differentially expressed genes (DEGs) involving PCD of pak choi were identified in the transcriptome data. The treatment suppressed the over-accumulation of reactive oxygen species (ROS) (superoxide anion O2·− and hydrogen peroxide H2O2), lipid membrane oxidation, ethylene production, and expression of their related genes (BcRBOHC, BcRBOHD, BcLOX1/3/5, BcACO, BcACO4 and BcEIN3)) during senescence. This relationship was also connected to the preservation of higher level in antioxidant capacity of antioxidase and antioxidants (ascorbate-glutathione (AsA-GSH)), as well as high expression of their related genes (BcSOD, BcAPX, and BcGR) in 1-MCP-treated pak choi. Moreover, 1-MCP down-regulated the transcript of genes involved in PCD, regulated the expression of genes associated with mitochondrial membrane transport, respiration and signaling, and chloroplast membrane transport and REDOX, thereby contributing to the inhibition of PCD. The correlation analysis revealed that pak choi yellowing was positively related with the process of PCD. Taken together, the present study indicated that 1-MCP could delay the yellowing of pak choi through mitigating PCD process, involving the regulation of ROS metabolism, membrane lipid degradation, antioxidant status and ethylene production.

Impact of Vanadium-Containing Stone Coal Smelting on Trace Metals in an Agricultural Soil-Vegetable System: Accumulation, Transfer, and Health Risks.

Dietary exposure to trace metals (TMs) through vegetable consumption has been identified as a potential risk to human health. Fifty-one paired agricultural soil and leaf vegetable samples were collected around V-containing stone coal smelting sites in Hunan Province, China, to study the contamination and transfer characteristics of TMs (Cd, Cr, Cu, Pb, V, and Zn) in the soil-vegetable system. The health risk to local residents through vegetable ingestion was evaluated using Monte Carlo simulations. The results showed that 96.2%, 23.1%, 53.8%, 30.8%, 96.2%, and 69.2% of the soil samples had Cd, Cr, Cu, Pb, V, and Zn contents exceeding their related maximum allowable values, respectively. Cadmium and V were the primary pollutants based on the Igeo values. Moreover, 46.9% and 48.4% of vegetable samples exceeded the maximum permissible levels for Cd and Pb, respectively. There was a negative correlation between the bioaccumulation factors for Cd and V of the vegetable and soil physicochemical properties, including pH, organic matter, and free Fe2O3 content. Ingestion of garland chrysanthemum and pak choi posed high health risks, and Cd, V, and Pb were the primary contributors. These findings will help design strategies to minimize contamination and human exposure to soil-vegetable systems caused by V-containing stone coal smelting.

Traditional processing techniques impacted the bioactivities of selected local consumed foods

Epidemiological and clinical studies have evidenced the crucial role of vegetables and mushrooms for our health. Vegetables and mushrooms are usually cooked before consumption which induces many physicochemical changes in foods. A change in the phytochemical content might alter the health benefits of the food. In this regard, the impact of domestic cooking particularly boiling, steaming and stir-frying at different time intervals (under-cooked, well-done and overcooking) on the phenolic content and antioxidant potential of locally grown Allium cepa L., Brassica chinensis L., Pleurotus sajor-caju and Moringa oleifera Lam leaves and pods were investigated. The anti-proliferative effects of the fresh and cooked vegetables were assessed on the hepatocellular carcinoma (HepG2) cell line. The results demonstrated a general increase in the phenolic content of A. cepa, P. sajor- caju, M. oleifera leaves and pods, but a decrease in B. chinensis after cooking. Both the raw and the cooked vegetables and mushroom demonstrated notable free radical scavenging abilities, potent ferric reducing antioxidant power and strong iron chelating activity across the different processing methods. Cooking significantly increased reducing potential of M. oleifera leaves and P. sajor-caju, while a significant decline was observed for B. chinensis and M. oleifera pods after thermal treatments. Boiling and stir-frying caused significant loss in the chelating potential of B. chinensis (p<0.05). In addition, cooking enhanced the anti-proliferative properties of B. chinensis, P. sajor-caju and M. oleifera leaves against liver cancer cells. The present data provide a new insight into the influence of conventional cooking methods on locally cultivated foods, highlighting the importance of choosing the appropriate processing technique to maximize bioaccessibility of the beneficial bioactive compounds.

Risk Assessment of Heavy Metal in Farmlands and Crops Near Pb–Zn Mine Tailing Ponds in Niujiaotang, China

To accurately evaluate the pollution and risk of heavy metals in crops and farmlands near mines, we determined the contents of Cr, Ni, Cu, As, Cd, Pb, and Zn in 10 farmland soil sampling sites and six crops (pak choi, rice, spring onion, radish, Chinese cabbage, Chrysanthemum coronarium) in an area near the Niujiaotang Pb-Zn mine in Duyun City, China. Four evaluation methods were compared, including the potential ecological hazard index, Nemeiro comprehensive pollution assessment, risk assessment code, and the ratio of secondary phase to primary phase methods. The average concentration of As, Cd, Pb, and Zn exceeded the soil environmental background levels in Niujiaotang and Guizhou Province. Cd exceeded the standard substantially, and Zn pollution accumulation was the most evident. Heavy metal contamination of crops was in the order pak choi > Chinese cabbage > spring onion > paddy > radish > Chrysanthemum coronarium, whereas heavy metal concentration in crops were in the order Zn > As > Cr > Cd > Ni > Pb. The levels of all heavy metals except Cu exceeded Chinese food hygiene standards. Carcinogenic and non-carcinogenic chemicals in crops present significant risks to adults and children. Risk evaluation considering the morphological contents of heavy metals rather than their total concentration was more accurate for environmental quality assessment of agricultural soils. Samples should be collected at different times to study the spatial and temporal distribution, and further studies on the migration transformation of heavy metals between the tailings pond-soil-crop should be conducted.

Genome insights into the plant growth-promoting bacterium Saccharibacillus brassicae ATSA2T

Endophytes can facilitate the improvement of plant growth and health in agriculturally important crops, yet their genomes and secondary metabolites remain largely unexplored. We previously isolated Saccharibacillus brassicae strain ATSA2T from surface-sterilized seeds of kimchi cabbage and represented a novel species of the genus Saccharibacillus. In this study, we evaluated the plant growth-promoting (PGP) effect of strain ATSA2T in kimchi cabbage, bok choy, and pepper plants grown in soils. We found a significant effect on the shoot and root biomass, and chlorophyll contents following strain ATSA2T treatment. Strain ATSA2T displayed PGP traits such as indole acetic acid (IAA, 62.9 μg/mL) and siderophore production, and phosphate solubilization activity. Furthermore, genome analysis of this strain suggested the presence of gene clusters involved in iron acquisition (fhuABD, afuABC, fbpABC, and fepCDG) and phosphate solubilization (pstABCHS, phoABHLU, and phnCDEP) and other phytohormone biosynthesis genes, including indole-3-acetic acid (trpABCDEFG), in the genome. Interestingly, the secondary metabolites cerecidin, carotenoid, siderophore (staphylobactin), and bacillaene underlying plant growth promotion were found in the whole genome via antiSMASH analysis. Overall, physiological testing and genome analysis data provide comprehensive insights into plant growth-promoting mechanisms, suggesting the relevance of strain ATSA2T in agricultural biotechnology.

Effects of Different Combined Passivators on Cadmium Availability in Contaminated Soils and Uptake by Pakchoi (&lt;i&gt;Brassica chinensis&lt;/i&gt; L.)

Effects of Different Combined Passivators on Cadmium Availability in Contaminated Soils and Uptake by Pakchoi (&lt;i&gt;Brassica chinensis&lt;/i&gt; L.)

Calcium carbonate-modified plant sporopollen capsule as an eco-friendly microvehicle for controlled release of pesticide.

In this work, natural club moss (Lycopodium clavatum, LC) spores with a porous surface morphology and highly uniform size distribution were engineered into controlled-release microvehicles for pesticide delivery. As a proof of concept, a widely used fungicide, fluazinam (FLU), was successfully loaded into LC spores and then modified with different amounts of CaCO3 (CaC) to extend the efficacy duration of FLU. Significantly, as the control target of FLU, clubroot disease is a worldwide destructive disease of cruciferous crops, and its development is favored by acidic soils and can be suppressed at high Ca concentrations. Fabricated FLU@LC-CaC microcapsules, FLU loading and CaCO3 deposition were systematically characterized by field emission scanning electron microscopy, Fourier transform infrared spectroscopy, and thermogravimetric analysis. The as-prepared FLU@LC-CaC microcapsules showed sustained-release behaviors and were potentially able to supplement the Ca concentration in acidic environments. This approach synergistically enhanced in vivo bioactivity for the on-demand control of clubroot disease. An in vivo bioassay revealed that the control efficacy of FLU@LC-CaC against clubroot disease in pak choi (Brassica chinensis) (66.4%) was 1.7-fold higher than that of a commercial FLU suspension concentrate (38.2%) over the course of the cultivation period (35 days). This work provides new ideas not only for developing eco-friendly and scalable microvehicles for pesticide delivery based on natural sporopollen, but also for unconventional research perspectives in on-demand pest management based on their occurrence characteristics. © 2022 Society of Chemical Industry.

Residual polyphenol oxidase and peroxidase activities in high pressure processed bok choy (Brassica rapa subsp. chinensis) juice did not accelerate nutrient degradation during storage

Polyphenol oxidase (PPO) and peroxidase (POD) cannot be fully inactivated by commercial high pressure processing (HPP) operations, and their residual activities may accelerate nutrient degradation during storage. This study hence aimed to establish the effect of residual enzyme activity on nutrient preservation in bok choy (Brassica rapa subsp. chinensis) juice. Bok choy juice was treated at 600 MPa for up to 20 min and enzyme inactivation, nutrient retention immediately after treatment and nutrient preservation during storage were determined. High residual PPO (85.1 ± 2.6%) and POD (68.5 ± 1.0%) activities remained after 20 min of treatment. Increasing the pressure holding time to enhance enzyme inactivation did not compromise total antioxidant capacity, vitamin C, carotenoids, isothiocyanates and vitamin K levels. Neither did it significantly reduce the vitamin C degradation rate during refrigerated storage. Maximising enzyme inactivation may thus not be necessary for nutrient preservation during the storage of HPP-treated bok choy juice. Industrial relevance textWith HPP, an increase in pressure or holding time is required to achieve higher levels of enzyme inactivation. Without the need to maximize PPO and POD inactivation, juice processors may employ the minimum pressure and holding time required for microbial inactivation. As vegetative bacteria are typically less resistant to HPP inactivation than these enzymes, this could translate to reduced energy costs and increased throughput.

Occurrence and fate of contaminants of emerging concern and their transformation products after uptake by pak choi (Brassica rapa subsp. chinensis)

Recovery and reuse of nutrients is a major challenge in agriculture. A new process contributing to a circular economy is the anaerobic digestion of food waste, which is a sustainable way of recycling nutrients as the digestate can be used as fertiliser in agriculture and horticulture. However, the digestate may be polluted with contaminants of emerging concern (CECs) that can be circulated back into the food chain, posing a risk to the environment and human health. In this work, the nutrient solution was spiked with 18 selected CECs frequently detected in food waste biogas facilities, and subsequent uptake and fate of these CECs were evaluated in pak choi grown in two different nutrient solutions (mineral and organic). All spiked compounds except two (propylparaben, fenbendazole) were taken up by pak choi plants, with perfluorobutanoic acid (PFBA) and sertraline displaying the highest concentrations (270 and 190 μg/kg fresh weight, respectively). There were no statistically significant differences in uptake between mineral and organic nutrient solutions. Uptake of per- and polyfluoroalkyl substances (PFAS) was negatively correlated with perfluorocarbon chain length and dependent on the functional group (r = −0.73). Sixteen transformation products (TPs) were tentatively identified using suspect screening, most of which were Phase II or even Phase III metabolites. Six of these TPs were identified for the first time in plant metabolism and their metabolic pathways were considered.

Efficient photo-oxidation remediation strategy toward arsenite-contaminated water and soil with zinc-iron layered double hydroxide as amendment

Arsenic contaminated water and soil is seriously threatening the ecosystems safety and human health. Specially, the As(III) has higher toxicity, mobility and lower affinity to typical adsorbents, thus posing substantial obstacles for remediation. Herein, we report a zinc-iron layered double hydroxide (ZnFe-LDH) that exhibits high removal capacity of 134.5 mg/g toward As(III) with the aid of photo-oxidation at the initial concentration of 200 mg/L with pH of 8.4, and can efficiently reduce the total concentration of As from 20 mg/L to 8.2 μg/L within 240 min, lower than the 10 μg/L upper limit for As in drinking water. Detailed investigations suggested that the active oxidative species of photogenerated holes, superoxide and hydroxyl radicals take part in the transformation of As(III) to As(V), which enhances the adsorption capacity. For As(III)-pollutant soil remediation, the bioavailability of As in soil dramatically decreased by 87.7% and 78.1% under visible and nature light in 3 days after introduction of ZnFe-LDH as in-situ immobilization amendment. Moreover, the plant cultivation experiment demonstrated that the bioaccumulation of As in Brassica chinensis effectively reduced to safety range after remediation of the As(III)-contaminated soil with ZnFe-LDH. We envision that the strategy of photocatalytic oxidation will open a new door to address the problem of As(III)-contaminated water and soil.

The effect of agricultural waste inhibit the uptake of Cadmium (Cd) by pak choi in assumption conditions of contaminated soil

This study aimed to explore the effects of agricultural waste (rice straw-RS and maize stalks-MS) in reducing Cd toxicity. Experiments in the study determined: growth of pak choi, total Cd concentration in the plant and the change in distribution of Cd fraction in the soil. Results showed that: agricultural waste application may detoxify Cd at excessive concentrations (3 and 6 mg/kg) by transforming mobile Cd fractions (EXC-Cd and CAB-Cd) into semi-mobile and non-mobile Cd fractions (FEM-Cd, OM-Cd, and RES-Cd); the Cd concentrations in pak choi decreased and pak choi growth increased. However, a significant reduction in Cd concentration can only occur when agricultural waste application is at an appropriate content (20 g/kg). In addition, agricultural waste application promoted the growth of pak choi at lower content (10 g/kg). Furthermore, this study also showed a good correlation between the ratio of mobile Cd fractions (EXC-Cd and CAB-Cd) with Cd concentration in pak choi and plant growth. This study suggested that agricultural waste application, especially rice straw, plays an important role in preventing Cd uptake by plant tissues at excessive concentrations through transformations into immobile Cd fractions.

Effects of application of nitrogen and vermicompost on growth performance and yield of Bari Chinashak-1 (Brassica chinensis L.)

A field experiment was carried out at the Horticulture Farm of Bangladesh Agricultural University, Mymensingh from March to May 2018 to investigate the effects of various doses of nitrogen and vermicomposton growth and yield performance of BARI Chinashak-1. The research work comprised of two factors, factor A: four doses of nitrogen viz., (i) N0-0 kg N/ha, (ii) N1-90 kg N/ha, (iii) N2-120 kg N/ha and (iv) N3-150 kg N/ha and factor B: Three doses of vermicompost viz.,(i) V0-0 ton/ha, (ii) V1-3 ton/ha and (iii) V2-5 ton/ha. The tallest plant (38.71 cm), maximum leafnumber /plant (13.99), highest length (34.99 cm) and breath (22.70cm) of leaves and maximum yield (26.27 t/ha) were recorded when 150 kg N/ha was applied. The shortest plant (31.03 cm), minimum leaf number/plant (11.82), shortest length (28.31 cm) and breath (18.50 cm) of leaves and minimum yield (18.34 t/ha) was found in the plots that did not get any nitrogen (0 kg N/ha). In case of vermicompost, the maximum plant height (36.79 cm), number of leaves/plant (13.97), the highest leaf length (33.84 cm) and breath (22.09 cm) and maximum total yield (24.70 t/ha) was observed at 5 ton/ha, whereas the shortest plant (33.32 cm), minimum number of leaves/plant (12.22), the lowest leaf length (29.68 cm) and breath (19.57 cm), and minimum total yield (20.98 t/ha) was observed with 0 ton/ha. For combined effect, the tallest plant (40.56 cm), maximum leaf number (15.33), length (36.50 cm) and breath (24.11 cm) of leaves, plant spread (77.10 cm) were observed from N3V2combination.

Optimization of a three-row air-suction Brassica chinensis precision metering device based on CFD-DEM coupling simulation

Optimization of a three-row air-suction Brassica chinensis precision metering device based on CFD-DEM coupling simulation

The effectiveness of biofertilizer biofilm formulation in promoting the growth of Pak choi (Brassica rapa L.) plant

One of the climate changes is the El Nino phenomenon, causing the soil to dry out, so it needs to be addressed because it will impact plant growth. Farmers use a lot of inorganic fertilizers (NPK), and in the long term, it can cause soil damage. One alternative treatment is to use organic fertilizers or biological fertilizers. Biofilm biofertilizer is a form of biological fertilizer. This study aims to determine the effect of dosing biofilm biofertilizer on the growth of Pak choi plants so that it can help reduce the use of inorganic fertilizers. This type of research was an experiment in a greenhouse using a completely randomized design (CRD) with six treatments, consisting of A (100% inorganic fertilizer), B (75% inorganic fertilizer and 25% biofilm biofertilizer), C (50% inorganic fertilizer and 50% biofertilizer biofilm), D (25% inorganic fertilizer and 75% biofertilizer biofilm), E (100% biofertilizer biofilm), and F (no inorganic fertilizer and no biofertilizer biofilm). Each treatment was repeated four times. Parameters used in this study included plant height, number of leaves, dry weight and wet weight, and leaf diameter. Data analysis used the ANOVA test with a 95% confidence level, followed by Duncan's Multiple Range Test (DMRT). The results showed that the combination of 25% biofertilizer biofilm treatment with 75% inorganic fertilizer gave the best results compared to the control and other treatments. The treatment of 25% Biofilm biofertilizer with 75% inorganic fertilizer was able to increase plant height by 21.175 cm or 74.24% higher than control, number of leaves by 17.25 strands or 65.62% higher than control, leaf width by 7.125 cm or 61.80% higher than control, wet weight by 28.083 g or 97.29% higher than control, and dry weight by 1.869 g or 95.88% higher than control so that this treatment can be an alternative to reduce the use of inorganic fertilizer.

Health risks of Cryptosporidium and Giardia in the application of surface water and septic tank effluent in Chinese agriculture: Impact on cancer patients identified by quantitative microbial risk assessment

The protozoa Cryptosporidium and Giardia are major causes of diarrhea and are commonly found on vegetables in China. They pose a health risk, particularly to immunocompromised individuals, including cancer patients. A quantitative microbial risk assessment of Chinese data evaluated the risks of Cryptosporidium and Giardia exposure arising from the application of surface water and septic tank effluent to agricultural land. Exposure via agricultural produce consumption (consumers) and agricultural practices (farmers) was considered for subpopulations of cancer patients and immunocompetent people in urban and rural areas, and risk mitigation scenarios were modelled. The cumulative disease burdens attributable to cryptosporidiosis and giardiasis were, respectively, 9.68×10−6 and 5.57×10−5 disability-adjusted life years per person per year (DALYs pppy) for immunocompetent people, and 3.14×10−5 and 1.51×10−4 DALYs pppy for cancer patients. Cancer patients were approximately three times more likely to have an individual disease burden than immunocompetent people. The disease burden was higher for consumers than farmers, and higher in rural areas than urban areas (all exceeding the maximum recommended by the World Health Organization). The highest burdens were in provinces of high population, such as Henan, Guangdong, and Sichuan, while the burden associated with human and livestock fecal effluent application was higher than with surface water irrigation. Of the three vegetables studied, lettuce posed the greatest risk, followed by bok choy, while cucumber posed the least risk. Risk mitigation scenario analysis showed that pre-treatment of surface water and feces, and appropriate post-harvest handling of vegetables, including disinfection, cooking, and adequate surface heat treatment (75 °C for 60 s), should be considered when attempting to reduce disease burdens. The methodology and findings of this study are useful for evaluating and reducing the burden of Cryptosporidium and Giardia infections associated with agricultural irrigation and fertilization practices, particularly on cancer patients.

Crawfish shell- and Chinese banyan branch-derived biochars reduced phytoavailability of As and Pb and altered community composition of bacteria in a contaminated arable soil

Globally, soil contamination with arsenic (As) and lead (Pb) has become a severe environmental issue. Herein, a pot experiment was conducted using pak choi (Brassica chinensis L.) to investigate the effects of biochars derived from crawfish (Procambarus clarkia) shells (CSB) and Chinese banyan (Ficus microcarpa) branches (CBB) on the phytoavailability of As and Pb, and bacterial community composition in soils. Our results showed that the application of CSB and CBB decreased the concentrations of DTPA-extractable Pb in soils ranging from 26.8 % to 28.8 %, whereas CSB increased the concentration of NH4H2PO4-extractable As in soils, compared to the control. Application of both biochars reduced the uptake of As and Pb in the edible part of pak choi. In addition, application of CBB significantly (P < 0.05) increased the activities of α-glucosidase, β-glucosidase, cellobiohydrolase, and acid phosphomonoesterase by 55.0 %, 54.4 %, 195.1 %, and 76.7 %, respectively, compared to the control. High-throughput sequencing analysis revealed that the predominant bacteria at the phyla level in both biochar-treated soils were Firmicutes, Proteobacteria, and Actinobacteriota. Redundancy and correlation analyses showed that the changes in bacterial community composition could be related to soil organic carbon content, As availability, and nutrient availability in soils. Overall, the Chinese banyan branch biochar was more suitable than the crawfish shell biochar as a potential amendment for the remediation of soils co-contaminated with As and Pb.

Exogenous melatonin ameliorates yellowing of postharvest pak choi (Brassica rapa subsp. chinensis) by modulating chlorophyll catabolism and antioxidant system during storage at 20 °C

The objective of this study was to investigate the regulatory mechanism of melatonin (MT) treatment on leaf yellowing of pak choi during storage at 20 °C. Results showed that 500 μmoL L−1 MT alleviated the yellowing process of pak choi as proved by the maintenance of high level of leaf colour, chlorophyll content and chlorophyll fluorescence parameters (Fo, Fm and Fv/Fm), and the market life of pak choi was extended by 2 d compared to the control. The weight loss and respiration rate were effectively alleviated by MT treatment. MT treatment restrained chlorophyll breakdown by down-regulating the activity of chlorophyll-degrading enzymes (chlorophyllase CLH, pheophytinase PPH and Mg-dechelatase MDS) and expression of their related genes (BcCLH, BcPPH1/2, BcSGR, BcHCAR, BcNYC1 and BcCAO). Meanwhile, MT suppressed the over-accumulation of reactive oxygen species (ROS) (superoxide anion O2·− and hydrogen peroxide H2O2), and lipid membrane oxidation and associated gene (BcLOX) expression during senescence, thus helping to keep green colour of pak choi. This relationship was also connected to the maintenance of higher level in antioxidant ability of antioxidase (superoxide dismutase SOD, ascorbate peroxidase APX, peroxidase POD and catalase CAT) and antioxidants (ascorbate-glutathione (AsA-GSH)), as well as high expression of their related genes (BcSOD, BcPOD, BcCAT, BcGPX and BcAPX) in pak choi treated with MT. In conclusion, these findings suggested that MT could delay the yellowing of pak choi, involving the regulation of chlorophyll metabolism, ROS metabolism, membrane lipid degradation, and antioxidant capacity. The results provide a possible target for delaying the yellowing of green vegetables.

1-Methylcyclopropene retards pak choi (Brassica rapasubsp. chinensis) yellowing via BcNAC055-, BcMYB44-, and BcOBF1-mediated regulation of the key chlorophyll degrading geneBcNYC1during storage at 20 °C

AbstractThe objective of this study was to investigate the molecular regulatory mechanism of 1-methylcyclopropene (1-MCP) treatment on leaf yellowing of pak choi during storage at 20 °C. In the present study, compared with the control and 10 μL/L ethylene-treated pak choi, 5.0 μL/L 1-MCP fumigation alleviated the yellowing process of pak choi as proved by the maintenance of higher levels of colour, chlorophyll content, and appearance. 1-MCP treatment decreased chlorophyll breakdown by downregulating the activity of chlorophyll-degrading enzymes (chlorophyll b reductase (CBR) and pheophytinase (PPH)) and the expression of their related genes (BcNYC1 and BcPPH). The application of 1-MCP also inhibited the transcript abundance of ethylene biosynthesis and signal transduction genes (BcACO, BcEIN3, and BcERF) and reduced ethylene production, thus helping to maintain the green colour of pak choi; however, ethylene treatment exerted the opposite function. Meanwhile, three transcription factors (BcNAC055, BcMYB44, and BcOBF1) were successfully cloned. Experiments performed using yeast one-hybrid assay, dual-luciferase reporter system and in vivo bioluminescence imaging assay, confirmed that BcNAC055, BcMYB44, and BcOBF1 directly bound to the BcNYC1 promoter. 1-MCP inhibited the expression levels of BcNAC055, BcMYB44, BcOBF1, and BcNYC1 during storage, while the application of ethylene activated their expression. In conclusion, 1-MCP downregulated the expression of the key chlorophyll degradation gene BcNYC1 by inhibiting the transcript level of its three positive regulators (BcNAC055, BcMYB44, and BcOBF1) and lowered the activity of chlorophyll-degrading enzyme CBR, thereby helping mitigate chlorophyll breakdown to retard leaf yellowing in pak choi. The results of this work extend our understanding of 1-MCP-delayed yellowing in postharvest pak choi.

Feasibility Analysis of Pakcoy (Brassica chinensis L.) Cultivation with Hydroponic System Using Several Types of Planting Media

Feasibility Analysis of Pakcoy (Brassica chinensis L.) Cultivation with Hydroponic System Using Several Types of Planting Media

Growth and Yield of Screenhouse-grown potted Pechay (Brassica rapa L. ssp. chinensis cv. Black Behi) in selected Davao-produced Composts

Pak choi (Brassica rapa subsp. chinensis), locally called pechay, is a nutritious and sought-after vegetable among Asian consumers as its edible petioles and green leaves are suitable in various recipes. The use of composts and organic amendments is integral to organic agriculture which is promoted in Davao City, Philippines. However, there are no published local studies in the city on the effect of recently formulated composts on crops. Thus, this study explored how these compost amendments affect the growth and yield of potted Black Behi pechay under screenhouse conditions using a completely randomized design. Results revealed that germination was higher in seeds sown in pure potting mix (90 to 94 %) and vermicompost-amended potting mixes (94 to 100 %) than with Dr. Bo’s Biofertilizer (DBB) (75 to 92%). Mean plant height (18.42 cm), leaf length (10.31 cm) and leaf width (5.89 cm) were highest in plants grown in potting mixes amended with 20% Tacunan vermicompost (Tacunan). Furthermore, there were pest and disease incidences in plants under all treatments but the least incidence was observed in plants grown in DBB. Total fresh weight (14.71 g), dry weight (0.76 g) and marketable fresh weight (12.19 g) obtained were exhibited by plants grown in 20% Tacunan. Total biomass, however, was highest in the urea-amended potting mix (15.42%). Results revealed that the application of composts positively influenced the growth and development of Black Behi pechay with 20% Tacunan as the recommended amendment.