Pakchoi Cabbage Research Articles

Silicon Improves Soil Environment and Promotes Crop Growth under Compound Irrigation via Brackish Water and Reclaimed Water

Not only is solving freshwater resource shortages effective but also an important measure for realizing the sustainable development of agriculture through the development and use of unconventional water resources. This pot experiment investigated the role of exogenous silicon in the risk of secondary soil salinization and the growth physiology of Lvxiu pakchoi cabbage under irrigation by using brackish water alone (BW), reclaimed water alone (RW), and compound irrigation with brackish water and reclaimed water at a ratio of 1:1, as well as the distribution of silicon in a soil–crop system. The results showed that with the extension of the spraying period of silicon fertilizer, the electrical conductivity (EC) decreased under 1:1 compound irrigation. The pH values in all treatments ranged from 7.95 to 8.10 without a potential risk of alkalization. Spraying silicon fertilizer had a positive effect on increasing the ratio of exchangeable potassium to sodium in soil. Spraying silicon fertilizer significantly reduced the percentage of exchangeable sodium (ESP) and the sodium adsorption ratio (SAR) in soils irrigated using BW, and increased the soil ESP and SAR under compound irrigation and RW irrigation, but these factors did not exceed the threshold of soil salinization. The proper application of silicon fertilizer had no significant effect on the total silicon content in the soil but increased the total silicon content in the plants to some extent. In addition, the yield was improved through proper silicon fertilizer application. In summary, exogenous silicon has positive effects on soil physical and chemical properties and crop growth, and relieves secondary salinization risk under compound irrigation via brackish water and reclaimed water.

Использование бактериальной инокуляции для улучшения вегетативного роста и нутрицевтических качеств китайской капусты в условиях регулируемой агроэкосистемы

Abstract. In recent years, plant inoculation with beneficial plant growth-promoting microorganisms PGPR bacteria in agriculture has been steadily increasing, and they are expected to partially replace chemical fertilizers, pesticides and other growth regulators in the future, providing an environmentally friendly solution for sustainable farming practices. Consequently, the purpose of this study was to investigate the bacterial inoculation of Bacillus cereus to improve the vegetative growth and nutraceutical qualities of Chinese cabbage pak-choi plants grown by hydroponics under regulated agroecosystem conditions. Objects of the study are the plants of Chinese cabbage pak-choy (Brassica campestris ssp. cheninsis L.). Methods. When conducting research, we measured biometric indicators, determined the indicators of crude, dry matter, dietary fiber and mass fraction of ash of pak-choy plants according to GOST. The contents of vitamins, cations, anions and amino acids in plant products were estimated by capillary electrophoresis using “Kapel’-205” device (Russia). The obtained results were processed statistically by means of analysis of variance. Scientific novelty. The efficiency of root inoculation of Bacillus cereus bacteria in the cultivation of pak-choy plants by hydroponics in closed agro-ecosystems has been determined. The dependence of the improvement of quality indicators in the biomass of bacterial inoculation of pak-choi plants has been established. Results. As a result of studies, it was found that the inoculation of B. cereus had a positive effect on the development of the assimilating apparatus of pak-choi plants. The formation of the main morpho-biometric parameters (crude, dry weight, shoot length and number of leaves) of plants was not significantly affected by bacterial inoculation. All obtained values were at the control level. Pak-choi plants inoculated with bacteria showed a significant increase in concentration of mineral elements (K, S and P), amino acids (proline, phenylalanine, valine, histidine and lysine) and vitamins (ascorbic acid and choline).

Effects of Polystyrene Microplastics on Growth, Physiology, Biochemistry, and Canopy Temperature Characteristics of Chinese Cabbage Pakchoi (Brassica chinensis L.)

The aim of this study was to clarify the response characteristics of Chinese cabbage pakchoi (Brassica chinensis L.) under two particle size (100 nm and 1000 nm) polystyrene microplastic (PS-MPs) stress conditions. This study can provide a theoretical basis and experimental reference for the interpretation of the physiological and ecological mechanism of microplastic pollution and the bioremediation of microplastic-contaminated soil. Hydroponic experiments were carried out to study the effects of two particle sizes (100 nm and 1000 nm) of PS-MPs on growth, photosynthetic physiology, antioxidant enzyme activities, nutritional quality, anatomical structure, and canopy temperature in Chinese cabbage pakchoi. The results showed that PS-MPs stress significantly inhibited the growth and development of Chinese cabbage pakchoi. When PS-MPs stress was increased, the phenotypic indicators were significantly reduced. Meanwhile, PS-MPs stress significantly enhanced the oxidative stress response of Chinese cabbage pakchoi, such as the activities of catalase (CAT), peroxidase (POD), superoxide dismutase (SOD), and ascorbate peroxidase (APX) and the content of malondialdehyde (MDA) in leaves. Such a change tended to decrease the thickness of fenestrated and leaf and spongy tissues. Moreover, PS-MPs stress significantly increased the canopy population temperature of the Chinese cabbage pakchoi leaves. Microplastic stress had obvious inhibitory effects and toxic damage on the growth, development, and physical and chemical properties of Chinese cabbage pakchoi.

Preparation of High Water-Soluble Trichoderma Co-Culture Metabolite Powder and Its Effects on Seedling Emergence Rate and Growth of Crops.

Trichoderma spp. are widely used beneficial microbes in agricultural production; however, the improper carrier choice for Trichoderma agent preparation can alter the effectiveness of Trichoderma fungicides. In this study, the co-culture of four Trichoderma strains produced a large amount of free amino acids, with a content of 392.8414 ug/mL, and significantly improved the production level of γ-aminobutyric acid. A greenhouse experiment further showed that the co-culture of Trichoderma synergistically improved the female flower development and bacterial angular leaf spot resistance. The effects of ten kinds of carriers were compared in terms of water absorption and heat generation, as well as their effects on the seedling emergence rate and the plant growth promotion of maize, cucumber, and pakchoi cabbage. Each carrier was screened to mix with four strains of co-culture metabolites to prepare highly soluble and quality powders. The results showed that there were different effects of the carriers themselves and Trichoderma strain co-culture metabolite powder prepared with the carriers on seedling emergence rate and seedling growth. Β-cyclodextrin performed best in high solubility and low heat generation upon absorbing water and in easy drying in processing operations. Trichoderma strains co-culture metabolite powder with β-cyclodextrin as a carrier provided the most obvious promotion effects on seedling emergence rate and seedling growth. Therefore, β-cyclodextrin was determined to be an ideal carrier to prepare a highly water-soluble Trichoderma agent. Taken together, the study successfully developed a new type of highly soluble powder containing Trichoderma co-culture metabolites that is expected to benefit farming drip irrigation and spraying systems for the promotion of crop growth and disease control.

Metabolomics reveals the molecular mechanism of sewage sludge-derived nutrients and biostimulants stimulating resistance enhancement and the redistribution of carbon and nitrogen metabolism in pakchoi cabbage

Alkaline thermal hydrolysis of sewage sludge to produce high-quality liquid fertilizer that contains protein, amino acid, organic acid and biostimulants is receiving wide attention, however, the impact on plants and environmental risks must be evaluated for sustainable use. In this study, the interactions between sewage sludge-derived nutrients, biostimulants (SS-NB), and pakchoi cabbage were investigated by a combination of phenotypic and metabolic approaches. Compared with SS-NB0 (single chemical fertilizer), SS-NB100, SS-NB50, and SS-NB25 had no effect on crop yield, but the net photosynthetic rate increased from 1.13 % to 9.82 %. In addition, the antioxidant enzyme activity (SOD) increased from 29.60 % to 71.42 %, with decreasing malondialdehyde (MDA) and H2O2 levels by 84.62–92.93 % and 8.62–18.97 %, respectively, indicating positive effects on photosynthetic and antioxidant capacities. Leaf metabolomics revealed that SS-NB100, SS-NB50, and SS-NB25 resulted in up-regulation of amino acid and alkaloid metabolites, down-regulation of carbohydrate metabolites, and up-regulation and down-regulation of organic acid metabolites, which were involved in carbon and nitrogen redistribution. Galactose metabolism was inactivated by SS-NB100, SS-NB50, and SS-NB25, indicating the protective role of SS-NB in oxidative damage in cells. Furthermore, the application of SS-NB also resulted in a significant reduction in heavy metal contents (Cr, Ni, and Pb) and the target hazard quotient (THQ). The THQ values of Cd, Cr, Ni and Pb were <1.0 in SS-NB50, and may be considered as an optimal fertilization strategy. The result provided better understanding of the phenotypic and metabolic changes imposed by SS-NB-replaced chemical fertilizer nitrogen in pakchoi cabbage leaves.

Growth, physiological, and temperature characteristics in chinese cabbage pakchoi as affected by Cd- stressed conditions and identifying its main controlling factors using PLS model

BackgroundAlthough hormesis induced by heavy metals is a well-known phenomenon, the involved biological mechanisms are not fully understood. Cadmium (Cd) is a prevalent heavy metal in the environment. Exposure of Cd, via intake or consumption of Cd-contaminated air or food, poses a huge threat to human health. Chinese cabbage pakchoi (Brassica chinensis L.) is widely planted and consumed as a popular vegetable in China. Therefore, studying the response of Chinese cabbage pakchoi to Cd- stressed conditions is critical to assess whether cabbage can accumulate Cd and serve as an important Cd exposure pathway to human beings. In this study, we investigated the influence of Cd stress on growth, photosynthetic physiology, antioxidant enzyme activities, nutritional quality, anatomical structure, and canopy temperature in Chinese cabbage pakchoi. A partial least squares (PLS) model was used to quantify the relationship between physical and chemical indicators with Cd accumulation in cabbage, and identify the main controlling factors.ResultsResults showed that Cd stress significantly inhibited cabbage’s growth and development. When Cd stress was increased, the phenotypic indicators were significantly reduced. Meanwhile, Cd stress significantly enhanced the oxidative stress response of cabbage, such as the activities of catalase (CAT), superoxide dismutase (SOD), peroxidase (POD), ascorbate peroxidase (APX), and the content of malondialdehyde (MDA) in leaves. Such a change tended to increase fenestrated tissues’ thickness but decrease the thickness of leaf and spongy tissues. Moreover, Cd stress significantly increased soluble sugar, protein, and vitamin C contents in leaves as well as the temperature in the plant canopy. The PLS model analysis showed that the studied phenotypic and physicochemical indicators had good relationships with Cd accumulation in roots, shoots, and the whole plant of cabbage, with high coefficient of determination (R2) values of 0.891, 0.811, and 0.845, and low relative percent deviation (RPD) values of 3.052, 2.317, and 2.557, respectively. Furthermore, through analyzing each parameter’s variable importance for projection (VIP) value, the SOD activity was identified as a key factor for indicating Cd accumulation in cabbage. Meanwhile, the effects of CAT on Cd accumulation in cabbage and the canopy mean temperature were also high.ConclusionCd stress has significant inhibitory effects and can cause damage cabbage’s growth and development, and the SOD activity may serve as a key factor to indicate Cd uptake and accumulation in cabbage.

Recovery of NH4 +-N and PO4 3--P from urine using sludge-derived biochar as a fertilizer: performance and mechanism.

Sludge-derived biochar (BS) was prepared by pyrolyzing municipal sludge at different temperatures and was used to recover NH4+–N and PO43−–P from urine. The effects of dosage, adsorption time, and urine concentration on the adsorption of NH4+–N and PO43−–P were investigated, and the adsorbed BS was used as a fertilizer to study its effect on the growth of pakchoi cabbage. The Elovich model was more consistent with the adsorption processes of NH4+–N and PO43−–P. Both the NH4+–N and PO43−–P adsorption isotherm model agreed with the Redlich–Peterson model. The Langmuir model showed that the largest adsorption capacity of BS600 for NH4+–N and PO43−–P could reach 114.64 mg g−1 and 31.05 mg g−1, respectively. The NH4+–N adsorption mechanism of BS may have complexation with O-containing functional groups and precipitation reactions, while the removal mechanism of PO43−–P was co-precipitation. The pot experiment demonstrated that adsorbed BS600 can better promote the growth of pakchoi cabbage with the same amount of addition. With the addition of 5% adsorbed BS600, the weight of cabbage was 64.49 g heavier than without the addition of BS600. This research provided theoretical support for the recovery of NH4+–N and PO43−–P from urine as a fertilizer.

Agricultural planning by selecting food crops with low arsenic accumulation to efficiently reduce arsenic exposure to human health in an arsenic-polluted mining region

Agricultural planning via substitution with crops of low arsenic (As) accumulation can efficiently reduce the dietary exposure from As to human health through food chain. In this study, in total 157 crop cultivars, including rice, vegetable and maize, were used and their risk of As accumulation in edible parts was studied via pot and field experiments. When soil As level was 56.7 mg kg−1, equivalent to a level of slight contamination, inorganic As (iAs) in rice grain ranged from 0.44 to 0.61 mg kg−1 Fresh weight (FW), which was 2.2–3.0 times higher than its limit in China (0.2 mg kg−1). When soil As enhanced to 156.2 mg kg−1 (moderate contamination), mater convolvulus and crown daisy had the over-limit risk of As accumulation in their edible parts. Green tender, pakchoi cabbage, rape and amaranth emerged with the over-limit risk of As, when soil As reached 238.3 mg kg−1 (severe contamination). Comparatively, maize and tuber or fruit vegetables had the lower levels of As in their edible parts and sweet potato, peanut, pepper and potato had less variation of As accumulation among cultivars of the same crop. A recommended list was provided for preferable food crops under different contamination level of As in soils. Switching paddy soil into upland soils and planting in priority with tuber or fruit vegetables and maize are encouraged. Agricultural planning resulted in significant decreases for the target hazard quotient (THQ) and target cancer risk (TCR) of iAs via dietary exposure to the residents near the realgar mine in Shimen County of China.

Effects of amendments on the bioavailability, transformation and accumulation of heavy metals by pakchoi cabbage in a multi-element contaminated soil.

This study aims to assess the effect of green waste compost (GWC), biochar (BC) and humic acid (HA) amendments of an alkaline heavy metal-contaminated soil. In this study, amendments with GWC, GWC + BC and GWC + HA were applied to the heavy metal-contaminated soil in four application rates (0, 1, 2 and 5%), and was aimed at substantially mitigating the bioavailability of heavy metals for pakchoi cabbage from the sewage irrigation soils. The addition of different ratios of amendments can increase the pH of the soil by 0.11–0.30 units and also increase the organic matter content by 3.1–35.1%. The concentration of available arsenic (As), cadmium (Cd), zinc (Zn) and copper (Cu) in the CaCl2 extract was decreased effectively by all the amendments, except for the increase in the available concentration of As by compost–humic acid (T8) in the soil. Compared with the control, the CaCl2 extractable Cd was decreased by 33–48% after the addition of different ratios of amendments in the soil. Moreover, by increasing the content of compost and compost–biochar in combinations, easily exchangeable fractions of As, Cd, Zn and Cu were decreased, while the oxidation fraction and residual fractions were increased. When the soil amendments were applied, fresh weight of the root and shoot increased by 29–63% and 39–85%, respectively. Cd concentration in the roots and shoots of the pakchoi cabbage decreased by 21–44% and 26–53%, respectively, after adding different ratios of amendments. All the amendments were effective in reducing the Cd, Zn and Cu uptake by the roots and shoots of the pakchoi cabbage, and simultaneously reduce the absorption of As in the roots of pakchoi cabbage. As soil amendments, GWC alone or GWC + BC/GWC + HA application can significantly reduce the heavy metal levels in pakchoi cabbage while increasing the biomass production and higher application rate is more effective than the lower application rate.

Insights from the Complete Genome Sequence of Bacillus circulans GN03, a Plant Growth-Promoting Bacterium Isolated from Pak Choi Cabbage (Brassica chinensis L.) Root Surface.

A plant growth-promoting rhizobacterium, Bacillus circulans GN03, was isolated from the root surface of pak choi cabbage. Here, we report the whole-genome sequence of the GN03 strain, which includes a circular chromosome (5,217,129 bp; GC content, 35.64%) and a plasmid (181,705 bp; GC content, 31.62%).

Remediation of Cd-contaminated soils by GWC application, evaluated in terms of Cd immobilization, enzyme activities, and pakchoi cabbage uptake.

Compost (mainly composed of cow manure, horse manure, chicken manure, and straw) has turned out to be effective in remediation of heavy metal-contaminated soil. However, in recent years, the effects of green waste compost (GWC) on plant growth and the immobilization of heavy metal cadmium (Cd) in the soil have not been clearly studied. We considered the effects of different GWC ratios on the growth of pakchoi cabbage, soil physical and chemical properties, total and availability of Cd content, and soil enzyme activity. The results showed that organic matter, total nitrogen, available phosphorus, and available potassium in the soil gradually put in place over the increase of compost proportion and showed a significant difference. Dehydrogenase, urease, and catalase activities grew by 380, 35, and 32% under the treatment of T10, respectively. The increase of enzyme activity indirectly reflects the enhancement of self-purification ability of contaminated soil. The addition of GWC improved soil quality, leading to a significant increase in soil nutrients, and in biomass and chlorophyll content of pakchoi cabbage. The decrease of Cd availability led to a significant reduction of Cd content in pakchoi cabbage, with a 30-36% reduction of Cd content in roots and a 43-69% reduction in leaf. The BCF of leaves decreased from 0.62 to 0.22, and the TF decreased from 0.94 to 0.46, indicating that the addition of GWC reduced the mobility of Cd to pakchoi cabbage leaves. The result is decreased in Cd content in edible parts of pakchoi cabbage.

Influence of green waste compost on Pb-polluted soil remediation, soil quality improvement, and uptake by Pakchoi cabbage (Brassica campestris L. ssp).

Green waste compost (GWC) has been widely used as organic mulches, growing media, soil organic fertilizer, and amendment in Beijing, China. The aim of this study is to determine the remediation efficiency of GWC on the Pb concentration in soil and uptake by pakchoi cabbage and to assess the activities of dehydrogenase, urease, and catalase after applying GWC. Original soil samples were spiked with Pb (NO3)2 of 500mg/kg, and greenhouse pot experiment was carried out. Three seedlings of pakchoi cabbage (Brassica campestris L. ssp) were planted in plastic pots with mixture of soil amended with three levels of GWC (2%, 5%, and 10%, w/w). Soil and plant samples were collected over 45-day growth, after which Pb concentration and enzyme activities were assessed by laboratory analysis. The available Pb in soil and total Pb in roots and leaves of pakchoi cabbage greatly decreased after adding GWC, associated with significant increases in organic matter, water soluble organic carbon, total nitrogen, and available K and P, whereas pH was not a main factor controlling Pb speciation in this study. Activities of dehydrogenase, urease, and catalase were promoted with addition of GWC because physical properties, high organic matter, and organic carbon content rose by 9-fold, 40%, and 37% at 10% application rate, respectively. In conclusion, GWC could be an alternative option for the remediation of Pb-contaminated soil because of soil quality improvement and Pb reduction in soils and plants, without introducing extra heavy metals compared with other organic amendments.

Identification, evolution and functional inference on the cold-shock domain protein family in Pak-choi (Brassica rapa ssp. chinensis) and Chinese cabbage (Brassica rapa ssp. pekinensis)

ABSTRACT The cold shock domain proteins (CSPs) play important roles in plant developmental processes and stress responses. Multiple sequence alignments found that these CSPs all have a cold shock domain fragment. Phylogenetic tree analysis found that most BcCSPs were more closely related to BrCSPs than other crops. Furthermore, we observed the conserved intron/exon structural patterns of these CSP genes in Pak-choi, Chinese cabbage and Arabidopsis, all motif were observed to be conserved among several boxes subgroups. Comparative analysis of expression patterns of CSP genes in Pak-choi, Chinese cabbage and Arabidopsis suggest that the CSP genes play various roles in plants through qRT-PCR analysis. Further, the CSP expression pattern in different tissues (roots, stems and leaves) of Chinese cabbage was also studied. This study showed that these gene family members might play roles in abiotic stresses responses, and might benefit from their functional characterization and utilization in the resistance engineering of Pak-choi and Chinese cabbage.

Metal availability, soil nutrient, and enzyme activity in response to application of organic amendments in Cd-contaminated soil.

The study investigated the effects of organic amendments: green tea amendment (GTA) and oil cake amendment (OCA) on Cd bioavailability, soil nutrients, and soil enzyme activity in Cd-contaminated soil. The amendments were added to the soil at the doses of 1, 3, and 5% and were incubated for 45days. Then, pakchoi cabbage was planted to test the remediation effect of the above two organic amendments. The diethylenetriaminepentaacetic acid (DTPA)-extractable Cd in GTA and OCA treatments was reduced by 14.69-27.51 and 13.75-68.77%, respectively, compared to no amendment-applied treatment. The application of GTA and OCA notably decreased the proportion of exchangeable fraction of Cd, but increased the percentage of oxide and organic-bound fraction of Cd, thereby suppressing the uptake by pakchoi cabbage. Cd concentration of aboveground parts decreased by 8.21-18.05 and 7.77-35.89% in GTA and OCA treatments, respectively. Relative to the no amendment-applied treatment, both GTA and OCA had enhanced soil nutrients and enzyme activities largely. Redundancy analysis showed that organic matter, total P, available N, and DTPA-extractable Cd significantly affected the enzyme activities. Furthermore, the application of OCA at the dose of 5% was more effective in reducing bioavailable Cd, enhancing soil available nutrients and urease and catalase activities in contaminated soil. These results indicated that oil cake should be used to immobilize metal and improve fertility and quality of Cd-contaminated soil.

Evaluations of the DMPP on organic and inorganic nitrogen mineralization and plant heavy metals absorption

The use of biochemical technologies to regulate soil nitrogen (N) transformations is an important strategy to improve plant nutrient uptake and its quality. Effect of organic and inorganic N fertilizers combined application supplemented with the nitrification inhibitor 3,4-dimethyl pyrazole phosphate (DMPP) on N transformations in the soil and heavy metal uptake of pakchoi cabbage (Brassica campestris L. ssp. chinensis) was studied in three different kinds of soils (purplish clayey soil, red soil, and sandy loam soil). The results demonstrated that DMPP addition in the organic and inorganic N combined fertilization extended ammonium N retention, and greatly reduced nitrate and nitrite N concentrations in three soils. Compared to the regular organic and inorganic-N combined fertilizers, DMPP addition in this fertilization increased the pakchoi biomass by 9.8% to 15.8% and reduced its nitrate concentrations by 15.7% to 40.8%. Furthermore, DMPP addition in the combined organic and inorganic fertilization decreased the heavy metal content of Cu (7.8% to 25.6%), Zn (10.4% to 20.3%), and Cd (12.8% to 22.2%) in the plant. The addition of DMPP to the organic and inorganic-N combined fertilizers could decrease the heavy metal counterion nitrate uptake in the plant, alter soil pH and decrease the activity of Cu, Zn and Cd in the soil, and weaken the plant heavy metal uptake of Cd and Zn in the three soils. It is proposed that DMPP could be used to regulate N transformation in the soil and decrease the heavy metal content in the plant in the organic and inorganic N combined fertilization, thus improving plant quality and yields.

Toxicity of combined chromium(VI) and phenanthrene pollution on the seed germination, stem lengths, and fresh weights of higher plants.

Studies of the interaction and toxicity of pollutant combinations such as heavy metals and PAHs are of practical importance in the remediation and monitoring of the industrial soil environment. This study investigated the single and combined toxicity of chromium(VI) and phenanthrene on three important higher plants: mung beans (Phaseolus aureus), pakchoi cabbage (Brassica chinensis), and rice (Oryza sativa). In experiments using artificial soil matrix, the EC10 and EC20 of the two pollutants, alone and in combination, were analyzed with respect to seed germination, stem length, and above-ground fresh weight of these higher plants. The additive index method was used to evaluate the combined biological toxicity of chromium(VI) and phenanthrene. The results showed that the EC20 of chromium(VI) on the stem lengths of mung beans, pakchoi cabbage, and rice was 289, 248, and 550mgkg(-1), respectively. The corresponding EC20 values for the fresh weights of the three plants were 334, 307, and 551mgkg(-1). The EC20 of phenanthrene on the stem lengths of mung beans, pakchoi cabbage, and rice was 528, 426, and 628mgkg(-1), respectively. The corresponding EC20 values for the fresh weights of the three plants were 696, 585, and 768mgkg(-1). The EC20 of a combination of chromium(VI) and phenanthrene on the stem lengths of mung beans, pakchoi cabbage, and rice was 192, 173, and 279mgkg(-1), respectively, and 200, 205, and 271mgkg(-1) for the fresh weights of the three plants. The single and combined exposure of soil to chromium(VI) and phenanthrene had deleterious effects on plants in the early stage of growth. Overall, pakchoi cabbage was more sensitive than mung beans and rice. The two pollutants exerted synergistic effects on the stem lengths and above-ground fresh weights of both mung beans and rice but antagonistic effects on pakchoi cabbage. The results of this study also suggested pakchoi cabbage as a sensitive indicator of soil pollution.

Accumulation of selenium in a Chinese cabbage of a grade Pak-choi in the course of cultivation

Most agricultural areas of Russia have soils poor in mineral selenium, causing higher oncology risks for population of such areas. The way to control malignancy incidence is selenium fortification of soils and plants. This can be achieved by agrochemical enrichment of cultivated plants with nutritive substrates containing essential minerals and trace elements. The current study aimed to assay the effect of inorganic selenium on the rate of Chinese pakchoi cabbage biomass gain for the development of agrochemical techniques for introducing selenium. The optimal selenium introduction technique would demonstrate the best balance of biomass gain rate and selenium ion accumulation in organic matter. Selenium ion accumulation dynamic was assessed during controlled growth of plants in soils enriched with nutritive substrate containing inorganic selenium (potassium selenite). The amount of selenium in plants was determined by spectroscopy. Mathematical functions describing the selenium uptake dynamic of controlled grown plants have been found, including derivatives of these functions that led to obtaining the numerical values of the respective uptake rates. It has been found that agricultural techniques that involve introduction of selenium at intermediate and late stages of cultivation are optimal for plant growth dynamic, as introducing selenium at early stages of cultivation has a negative impact on biomass uptake rates. Additionally, introducing potassium selenite to the nutritive substrate at 1.0 mg×dm–3 proved to be more effective than introducing potassium selenite at 0.5 mg×dm–3 as the former dosage led to a better plant growth dynamic.

Uptake of three sulfonamides from contaminated soil by pakchoi cabbage

Uptake of three sulfonamides (SAs) including sulfadiazine (SDZ), sulfamethazine (SM2) and sulfamethoxazole (SMZ) by pakchoi cabbage from soil was evaluated by using pot experiment. SDZ, SM2 and SMZ spiked in soil could be taken up by pakchoi cabbage. SM2 and SMZ were accumulated more easily by pakchoi cabbage than SDZ. The dissipation half-lives of SMZ (16.8d) and SM2 (16.7d) in soil were significantly longer than SDZ (10.8d). The higher concentrations of SM2 and SMZ in pakchoi cabbage in comparison with that of SDZ could be attributed to the higher residual concentrations of SM2 and SMZ in soil. Increasing initial concentration of SM2 spiked in soil, the residual concentration of SM2 in soil increased and resulted in promoting SM2 uptake in pakchoi cabbage. Concentrations of SAs in pakchoi cabbage planted in combined sulfonamides polluted soil differ from that in single sulfonamide polluted soil, although the same concentration (5.0mg/kg) of SAs was spiked in soil. Combined SAs pollution in soil may enhance SAs uptake in pakchoi cabbage. The lower bacteria numbers in soil under combined pollution resulted in higher residual SAs concentrations in soil, which could be the main reason for higher SAs concentrations in pakchoi cabbage.

BcSKS11, a SKS gene from pollinated pistils of Chinese cabbage pak choi, is expressed continuously during the male gametophyte development, pollen germination and pollen-tube growth processes

Cell wall-related genes and proteins are crucial for fertilisation-related events such as pollen germination and pollen-tube growth. Recent studies have focussed on the molecular mechanism of cell-wall synthesis and regulation of these processes; however, limited information is available on the mechanism and modification of the crucial cell-wall materials. We isolated a gene that is potentially involved in cell-wall metabolism from pollinated pistils of the male sterile line ‘Bcajh97-A’ in Chinese cabbage pak choi (Brassica campestris SKewed5 Similar 11, BcSKS11). BcSKS11 has several features of SKewed5 Similar (SKS) proteins, which are structures that are similar to plant multicopper oxidase but lack the 10 necessary residues of two copper-binding sites. A phylogenetic tree constructed from 49 SKS proteins found four clades, with BcSKS11 being in a clade with tobacco sequences. Reverse transcription–polymerase chain reaction and in situ hybridisation revealed that BcSKS11 was specifically expressed in uninucleate microspores, mature pollen grains and growing pollen tubes of pollinated pistils. These results suggest that BcSKS11 might be stored in mature pollen grains, in preparation for pollen germination and pollen-tube growth.

Identification of gene expression profile during fertilization in Brassica campestris subsp. chinensis

Fertilization is controlled by a complex gene regulatory network. To study the fertilization mechanism, we determined time courses of the four developmental stages of fertilization in Chinese cabbage pak-choi (Brassica campestris subsp. chinensis) by cytological observation. We then used the Arabidopsis ATH1 microarray to characterize the gene expression profiles of pollinated and unpollinated pistils in B. campestris subsp. chinensis. The result showed 44 up-regulated genes and 33 down-regulated genes in pollinated pistils compared with unpollinated pistils. Gene ontology analysis identified 20% of the up-regulated genes as belonging to the category of cell wall metabolism. We compared the up-regulated genes in pollinated pistils with previously identified pollen development related genes. Ten genes were found to be in common, which were termed as continuously expressed genes, in the two processes in the present article. Their expression patterns during pollen development and fertilization processes were then verified by RT-PCR. One of the continuously expressed genes, the homologous gene of At3g01270 in B. campestris subsp. chinensis, was confirmed as specifically expressed in microspores and pollinated pistils by using in situ hybridization. The potential biological functions of the other continuously expressed genes were also discussed.