Flavonoids were the most important secondary metabolites in celery (Apium graveolens L.).In this study,the flavonoid (apigenin and luteolin) contents of leaves and petioles in 44 Chinese celery varieties,an Americ...Flavonoids were the most important secondary metabolites in celery (Apium graveolens L.).In this study,the flavonoid (apigenin and luteolin) contents of leaves and petioles in 44 Chinese celery varieties,an American celery variety ‘Ventura' and an European celery variety ‘Princer' were assayed by reversed-phase high-perfor mance liquid chromatography (RP-HPLC).The results showed that significant differences in the apigenin and luteolin contents of the leaves and petioles were found among 46 celery varieties,and the variation coefficients of leaf apigenin content,leaf luteolin content,leaf flavonoid content,petiole apigenin content,petiole luteolin content and petiole flavonoid content were 30%,10%,30%,20%,30% and 20%,respectively.There was no correlation between the leaf flavonoid content and petiole flavonoid content.The apigenin content was about 18 to 50 times of luteolin in celery leaf and about 19 to 40 times of luteolin in celery petiole.The flavonoids in most of the Chinese celery varieties were higher than in ‘Ventura' and ‘Princer'.The flavonoid contents of Chinese celery varieties from the Yangtze Valley and southern China were higher than those from northern China.Our results suggested that Chinese celery varieties with high petiole apigenin contents could be used for vegetable breeding because the petiole was the main edible part,and Chinese celery varieties with high leaf apigenin contents could be used for apigenin production.展开更多
This study aimed to investigate the effects of different irrigation amounts on water consumption and water use efficiency of celery under the condition of drip irrigation, so as to provide a scientific basis for high-...This study aimed to investigate the effects of different irrigation amounts on water consumption and water use efficiency of celery under the condition of drip irrigation, so as to provide a scientific basis for high-yielding, high-quality and highefficiency cultivation and water-saving irrigation of greenhouse celery. Total five irrigation amounts were designed, 117.5 (T1), 160.0 (T2), 202.5 (T3), 245.0 (T4) and 287.5 (CK) mm/hm2, and the effects of different irrigation amounts on yield, water consumption and water use efficiency of celery were studied by plot experiment. The results showed that at the soil depth of 0-40 cm, the soil water storages of different treatments ranked as T3's〉T4's〉CK's〉T2's〉T1's, and the celery water consumptions ranked as CK's〉T4's〉T3's〉T2's〉T1's. At the same time, the soil water storage in different treatment group declined with the growth of celery, and finally increased at the harvest period. Among different irrigation amounts, the water use effi- ciency and irrigation water use efficiency all ranked as T1's〉T2's〉T3's〉T4's〉CK's. The water consumption of celery was positively related to irrigation amount (P〈 0.01), and was negatively related to water use efficiency (P〈0.01) and irrigation water use efficiency (P〈0.05). When the irrigation amount was below 253 mm/hm2, the celery yield was positively related to irrigation amount (P〈0.01). There was also a positive correlation between celery output and irrigation amount. Compared with those of CK, the benefit of the T4 treatment group was equal, and the water consumption was reduced by 14.78%. In high-efficiency solar greenhouse, the irrigation amount of drip-irrigated celery is recommended as 245 mm/hm2.展开更多
[Objective] The paper was to study the climate conditions of celery indus- trial belt in Huluhe Basin. [Method] Using the climate data of Xiji national basic sta- tion during 1981 and 2010, the meteorological data dur...[Objective] The paper was to study the climate conditions of celery indus- trial belt in Huluhe Basin. [Method] Using the climate data of Xiji national basic sta- tion during 1981 and 2010, the meteorological data during crop growth period in 3 automatic weather stations along Huluhe Basin were carried out regression analysis, and the climate condition of west celery industrial belt was conducted hierarchical clustering analysis by SPSS. [Result] West celery industrial belt along Huluhe Basin could be divided into 2 growing regions: partially southern warm, rainy and early mature region, partially northern cold, rainless and late mature region. Years of practice proved that the small climate differences within 2 planting regions were more obvious, so these 2 planting regions could be further divided into 4 subre- glens: Xinglong warm, rainy and early mature subregion, Xiaohe thermal, rainy and partially early mature region, Jiqiang cool, rainless and middle mature subregion and Xinying cold, rainless and late mature subregion. [Conclusion] The study has refer- ence value for determination of different sowing time, different fertilizer and irrigation scheme, pests and diseased control and marketing time of west celery under mulch- sanded bunch plantation in market economic condition.展开更多
A pot experiment was conducted to study the bioaccumulation and translocation of cadmium (Cd) in cole (Brassica campestris L.) and celery (Apium graveolens) grown in the Cd-polluted oasis soil, Northwest of Chin...A pot experiment was conducted to study the bioaccumulation and translocation of cadmium (Cd) in cole (Brassica campestris L.) and celery (Apium graveolens) grown in the Cd-polluted oasis soil, Northwest of China. The results showed that Cd in the unpolluted oasis soil was mainly bound to carbonate fraction (F2) and Fe-Mn oxide fraction (F3). However, marked change of Cd fractions was observed with increasing soil Cd concentrations, in which the concentration of Cd in F1 (exchangeable fraction), F2 and F3 increased significantly (p 〈 0.001 for F1, F2 and F3). The growth of cole and celery could be facilitated by low concentrations of Cd, but inhibited by high cortcentmdons. The correlation analysis between the fraction distribution coefficient of Cd in the soil and Cd concentration accumulated in the two vegetables showed that Cd in F1 in the soil made the greatest contribution on the accumulation of Cd in the two vegetables. The high bio-eoncentration factor and the translocation factor of Cd in both cote and celery were observed, and Cd had higher accumulation in the edible parts of the two vegetables. Therefore, both cole and celery grown in Cd-polluted oasis soil have higher risk to human health. And the two vegetables are not suitable to be cultivated as vegetables consumed by human in the Cd-polluted oasis soil.展开更多
Glucosinolates(GLS) contribute to the unique flavour, nutrition, and plant defence of the Cruciferous vegetables. Understanding the GLS changes through postharvest processing is essential for defined preservation. In ...Glucosinolates(GLS) contribute to the unique flavour, nutrition, and plant defence of the Cruciferous vegetables. Understanding the GLS changes through postharvest processing is essential for defined preservation. In this study, four different fresh-cut types, whole flower(W),floret(F), quarterly cut floret(QF) and shredded floret(FS) of broccoli, were stored for 0, 1, 2 and 3 day(s) to explore GLS responses to postharvest treatments. As a result, seven GLS were identified, mainly including glucoraphanin(RAA), neoglucobrassicin(NEO), and glucobrassicin(GBC)and accounting for 52.69%, 20.12% and 14.99% of the total GLS(21.92 ± 0.48) μmol · g ^(-1 )DW, respectively. FS had the sharpest decrease in GLS after three days of storage(6.55 ± 0.37) μmol · g-1DW, while QF had the least(10.16 ± 0.33) μmol · g ^(-1 )DW. All GLS components decreased over storage, except for 4-methoxyglucobrassicin(4 ME) in FS and QF, suggesting its key role in serious wound defence. The results suggested certain postharvest approaches influenced the flavour and nutrition of broccoli.展开更多
Plant metabolites are important for plant development and human health.Plants of celery(Apium graveolens L.)with different-colored petioles have been formed in the course of long-term evolution.However,the composition...Plant metabolites are important for plant development and human health.Plants of celery(Apium graveolens L.)with different-colored petioles have been formed in the course of long-term evolution.However,the composition,content distribution,and mechanisms of accumulation of metabolites in different-colored petioles remain elusive.Using ultra-high performance liquid chromatography-tandem mass spectrometry(UHPLC-MS/MS),1159 metabolites,including 100 lipids,72 organic acids and derivatives,83 phenylpropanoids and polyketides,and several alkaloids and terpenoids,were quantified in four celery cultivars,each with a different petiole color.There were significant differences in the types and contents of metabolites in celery with different-colored petioles,with the most striking difference between green celery and purple celery,followed by white celery and green celery.Annotated analysis of metabolic pathways showed that the metabolites of the different-colored petioles were significantly enriched in biosynthetic pathways such as anthocyanin,flavonoid,and chlorophyll pathways,suggesting that these metabolic pathways may play a key role in determining petiole color in celery.The content of chlorophyll in green celery was significantly higher than that in other celery cultivars,yellow celery was rich in carotenoids,and the content of anthocyanin in purple celery was significantly higher than that in the other celery cultivars.The color of the celery petioles was significantly correlated with the content of related metabolites.Among the four celery cultivars,the metabolites of the anthocyanin biosynthesis pathway were enriched in purple celery.The results of quantitative real-time polymerase chain reaction(q RT-PCR)suggested that the differential expression of the chalcone synthase(CHS)gene in the anthocyanin biosynthesis pathway might affect the biosynthesis of anthocyanin in celery.In addition,HPLC analysis revealed that cyanidin is the main pigment in purple celery.This study explored the differences in the types and contents of metabolites in celery cultivars with different-colored petioles and identified key substances for color formation.The results provide a theoretical basis and technical support for genetic improvement of celery petiole color.展开更多
Thiophonate-methyl(TPM) is one of fungicides and pesticides widely used in agriculture field.However,the residue of its benzimidazole(BZD) metabolites in related agricultural products poses a potential risk to consume...Thiophonate-methyl(TPM) is one of fungicides and pesticides widely used in agriculture field.However,the residue of its benzimidazole(BZD) metabolites in related agricultural products poses a potential risk to consumers.In this paper,nickel oxide nanoparticle-deposited silica(SiO_2@NiO) composite was used for the selective enrichment and purification of TPM's BZD metabolites in celery cabbage sprayed with TPM.Meanwhile,high-performance liquid chromatography coupled with precursor ion scan-mass spectrometry(HPLC-PIS-MS) and high-resolution MS/MS analysis(HR-MS/MS) was utilized for their qualitative and quantitative analysis.Twenty-one potential TPM's BZD metabolites were found and four of them were identified.One metabolite was discovered for the first time.Besides,a robust and sensitive quantitative method was developed with good linearities(R^2> 0.9972) within a wide range of 10.00-1000 ng/g.The detection limits of three known TPM's metabolites were within the range of 3.20-4.90 ng/g.Relative standard deviations(RSDs) of intra-day and inter-day precisions were less than 18.3%,which showed perfect reproducibility.The method was successfully applied to monitoring TPM's BZD metabolites in celery cabbage sprayed with TPM and the concentration versus time curves of TPM's metabolites in celery cabbage were plotted.This method is expected to be used to monitor BZD residues in various fruits and vegetables.展开更多
In this study, forty celery cultivars introduced from different regions of China were used as experimental materials to verify and analyze the practicability of RAPD technology in the identification of celery cuhivars...In this study, forty celery cultivars introduced from different regions of China were used as experimental materials to verify and analyze the practicability of RAPD technology in the identification of celery cuhivars. The results showed that RAPD technology could distinguish accurately the genetic relationship among various celery cultivars as a simple and ideal DNA molecular marker technology suitable for genetic relationship analysis. To be specific, 13 RAPD primers with clear amplified bands and significantly different number of amplified bands were screened, which provided basis for the identification of genetic relationship among different celery cultivars.展开更多
Pectobacterium carotovorum is the causal agent of bacterial soft rot in a wide range of vegetable host species.Once P.carotovorum infects the plant,the spread of the disease is difficult to control.In this study,a rap...Pectobacterium carotovorum is the causal agent of bacterial soft rot in a wide range of vegetable host species.Once P.carotovorum infects the plant,the spread of the disease is difficult to control.In this study,a rapid and sensitive method based on loop-mediated isothermal amplification(LAMP)was developed for detecting P.carotovorum in celery with soft rot using a primer set designed from the pmrA conserved sequence of P.carotovorum.The specificity of the LAMP primer set for P.carotovorum was extensively validated on both P.carotovorum strains and nontarget strains.The sensitivity was 1 pg of P.carotovorum genomic DNA,which demonstrated 10 times more sensitive than the conventional PCR assay.LAMP was also used to detect P.carotovorum in bacterial suspension.The lowest detection concentration was 104 CFU·mL^−1.In addition,a LAMP assay,in conjunction with a crude DNA extraction method,was successfully performed on P.carotovorum-infected samples derived from both artificially and naturally infected plants.In summary,the LAMP assay established in this study constitutes a simple,sensitive,and rapid method for the detection of P.carotovorum,and has potential application in the control of celery soft rot disease through early detection.展开更多
基金Supported by Shanghai Green Vegetable Industrial Technology SystemKey Scienceand Technology Research Program of Science and Technology Commission of Shanghai Municipality(12391900900)+1 种基金Innovation Project of Science and Technology Foundation of Pudong New District(PKQ2012-03)Special Fund for Agro-scientific Research in the Public Interest(201403032)~~
文摘Flavonoids were the most important secondary metabolites in celery (Apium graveolens L.).In this study,the flavonoid (apigenin and luteolin) contents of leaves and petioles in 44 Chinese celery varieties,an American celery variety ‘Ventura' and an European celery variety ‘Princer' were assayed by reversed-phase high-perfor mance liquid chromatography (RP-HPLC).The results showed that significant differences in the apigenin and luteolin contents of the leaves and petioles were found among 46 celery varieties,and the variation coefficients of leaf apigenin content,leaf luteolin content,leaf flavonoid content,petiole apigenin content,petiole luteolin content and petiole flavonoid content were 30%,10%,30%,20%,30% and 20%,respectively.There was no correlation between the leaf flavonoid content and petiole flavonoid content.The apigenin content was about 18 to 50 times of luteolin in celery leaf and about 19 to 40 times of luteolin in celery petiole.The flavonoids in most of the Chinese celery varieties were higher than in ‘Ventura' and ‘Princer'.The flavonoid contents of Chinese celery varieties from the Yangtze Valley and southern China were higher than those from northern China.Our results suggested that Chinese celery varieties with high petiole apigenin contents could be used for vegetable breeding because the petiole was the main edible part,and Chinese celery varieties with high leaf apigenin contents could be used for apigenin production.
基金Supported by Special Fund for Agro-scientific Research in the Public Interest of China(201303133-3)Tianjin Science and Technology Plan Project(14ZCDGNC00108)Agricultural Science and Technology Achievements Transformation and Extension Project of Tianjin City(201203030)~~
文摘This study aimed to investigate the effects of different irrigation amounts on water consumption and water use efficiency of celery under the condition of drip irrigation, so as to provide a scientific basis for high-yielding, high-quality and highefficiency cultivation and water-saving irrigation of greenhouse celery. Total five irrigation amounts were designed, 117.5 (T1), 160.0 (T2), 202.5 (T3), 245.0 (T4) and 287.5 (CK) mm/hm2, and the effects of different irrigation amounts on yield, water consumption and water use efficiency of celery were studied by plot experiment. The results showed that at the soil depth of 0-40 cm, the soil water storages of different treatments ranked as T3's〉T4's〉CK's〉T2's〉T1's, and the celery water consumptions ranked as CK's〉T4's〉T3's〉T2's〉T1's. At the same time, the soil water storage in different treatment group declined with the growth of celery, and finally increased at the harvest period. Among different irrigation amounts, the water use effi- ciency and irrigation water use efficiency all ranked as T1's〉T2's〉T3's〉T4's〉CK's. The water consumption of celery was positively related to irrigation amount (P〈 0.01), and was negatively related to water use efficiency (P〈0.01) and irrigation water use efficiency (P〈0.05). When the irrigation amount was below 253 mm/hm2, the celery yield was positively related to irrigation amount (P〈0.01). There was also a positive correlation between celery output and irrigation amount. Compared with those of CK, the benefit of the T4 treatment group was equal, and the water consumption was reduced by 14.78%. In high-efficiency solar greenhouse, the irrigation amount of drip-irrigated celery is recommended as 245 mm/hm2.
基金Supported by Meteorological Science and Technology Project of Ningxia Meteorological Bureau in 2011 "West Celery Experiment of Sowing by Stages"~~
文摘[Objective] The paper was to study the climate conditions of celery indus- trial belt in Huluhe Basin. [Method] Using the climate data of Xiji national basic sta- tion during 1981 and 2010, the meteorological data during crop growth period in 3 automatic weather stations along Huluhe Basin were carried out regression analysis, and the climate condition of west celery industrial belt was conducted hierarchical clustering analysis by SPSS. [Result] West celery industrial belt along Huluhe Basin could be divided into 2 growing regions: partially southern warm, rainy and early mature region, partially northern cold, rainless and late mature region. Years of practice proved that the small climate differences within 2 planting regions were more obvious, so these 2 planting regions could be further divided into 4 subre- glens: Xinglong warm, rainy and early mature subregion, Xiaohe thermal, rainy and partially early mature region, Jiqiang cool, rainless and middle mature subregion and Xinying cold, rainless and late mature subregion. [Conclusion] The study has refer- ence value for determination of different sowing time, different fertilizer and irrigation scheme, pests and diseased control and marketing time of west celery under mulch- sanded bunch plantation in market economic condition.
基金supported by the National Environmental Protection Commonweal Project of China (No. NEPCP 200809098)the Fundamental Research Funds for the Central Universities in Lanzhou University (No. lzujbky-2009-65)the National Natural Science Foundation of China (No. 91025015)
文摘A pot experiment was conducted to study the bioaccumulation and translocation of cadmium (Cd) in cole (Brassica campestris L.) and celery (Apium graveolens) grown in the Cd-polluted oasis soil, Northwest of China. The results showed that Cd in the unpolluted oasis soil was mainly bound to carbonate fraction (F2) and Fe-Mn oxide fraction (F3). However, marked change of Cd fractions was observed with increasing soil Cd concentrations, in which the concentration of Cd in F1 (exchangeable fraction), F2 and F3 increased significantly (p 〈 0.001 for F1, F2 and F3). The growth of cole and celery could be facilitated by low concentrations of Cd, but inhibited by high cortcentmdons. The correlation analysis between the fraction distribution coefficient of Cd in the soil and Cd concentration accumulated in the two vegetables showed that Cd in F1 in the soil made the greatest contribution on the accumulation of Cd in the two vegetables. The high bio-eoncentration factor and the translocation factor of Cd in both cote and celery were observed, and Cd had higher accumulation in the edible parts of the two vegetables. Therefore, both cole and celery grown in Cd-polluted oasis soil have higher risk to human health. And the two vegetables are not suitable to be cultivated as vegetables consumed by human in the Cd-polluted oasis soil.
基金supported by the Collaborative Innovation Center of the Beijing Academy of Agriculture and Forestry Sciences(Grant No.KJCX201915)the Youth Scientific Research Funds of Beijing Academy of Agriculture and Forestry Sciences(Grant No.QNJJ201914)the Innovation and Capacity-building Project of Beijing Academy of Agriculture and Forestry Sciences(Grant No.KJCX20200213).
文摘Glucosinolates(GLS) contribute to the unique flavour, nutrition, and plant defence of the Cruciferous vegetables. Understanding the GLS changes through postharvest processing is essential for defined preservation. In this study, four different fresh-cut types, whole flower(W),floret(F), quarterly cut floret(QF) and shredded floret(FS) of broccoli, were stored for 0, 1, 2 and 3 day(s) to explore GLS responses to postharvest treatments. As a result, seven GLS were identified, mainly including glucoraphanin(RAA), neoglucobrassicin(NEO), and glucobrassicin(GBC)and accounting for 52.69%, 20.12% and 14.99% of the total GLS(21.92 ± 0.48) μmol · g ^(-1 )DW, respectively. FS had the sharpest decrease in GLS after three days of storage(6.55 ± 0.37) μmol · g-1DW, while QF had the least(10.16 ± 0.33) μmol · g ^(-1 )DW. All GLS components decreased over storage, except for 4-methoxyglucobrassicin(4 ME) in FS and QF, suggesting its key role in serious wound defence. The results suggested certain postharvest approaches influenced the flavour and nutrition of broccoli.
基金supported by the National Natural Science Foundation of China(No.32002027)。
文摘Plant metabolites are important for plant development and human health.Plants of celery(Apium graveolens L.)with different-colored petioles have been formed in the course of long-term evolution.However,the composition,content distribution,and mechanisms of accumulation of metabolites in different-colored petioles remain elusive.Using ultra-high performance liquid chromatography-tandem mass spectrometry(UHPLC-MS/MS),1159 metabolites,including 100 lipids,72 organic acids and derivatives,83 phenylpropanoids and polyketides,and several alkaloids and terpenoids,were quantified in four celery cultivars,each with a different petiole color.There were significant differences in the types and contents of metabolites in celery with different-colored petioles,with the most striking difference between green celery and purple celery,followed by white celery and green celery.Annotated analysis of metabolic pathways showed that the metabolites of the different-colored petioles were significantly enriched in biosynthetic pathways such as anthocyanin,flavonoid,and chlorophyll pathways,suggesting that these metabolic pathways may play a key role in determining petiole color in celery.The content of chlorophyll in green celery was significantly higher than that in other celery cultivars,yellow celery was rich in carotenoids,and the content of anthocyanin in purple celery was significantly higher than that in the other celery cultivars.The color of the celery petioles was significantly correlated with the content of related metabolites.Among the four celery cultivars,the metabolites of the anthocyanin biosynthesis pathway were enriched in purple celery.The results of quantitative real-time polymerase chain reaction(q RT-PCR)suggested that the differential expression of the chalcone synthase(CHS)gene in the anthocyanin biosynthesis pathway might affect the biosynthesis of anthocyanin in celery.In addition,HPLC analysis revealed that cyanidin is the main pigment in purple celery.This study explored the differences in the types and contents of metabolites in celery cultivars with different-colored petioles and identified key substances for color formation.The results provide a theoretical basis and technical support for genetic improvement of celery petiole color.
基金The National Natural Science Foundation of China(No.31671929,21635006 and 31670373)supported this work。
文摘Thiophonate-methyl(TPM) is one of fungicides and pesticides widely used in agriculture field.However,the residue of its benzimidazole(BZD) metabolites in related agricultural products poses a potential risk to consumers.In this paper,nickel oxide nanoparticle-deposited silica(SiO_2@NiO) composite was used for the selective enrichment and purification of TPM's BZD metabolites in celery cabbage sprayed with TPM.Meanwhile,high-performance liquid chromatography coupled with precursor ion scan-mass spectrometry(HPLC-PIS-MS) and high-resolution MS/MS analysis(HR-MS/MS) was utilized for their qualitative and quantitative analysis.Twenty-one potential TPM's BZD metabolites were found and four of them were identified.One metabolite was discovered for the first time.Besides,a robust and sensitive quantitative method was developed with good linearities(R^2> 0.9972) within a wide range of 10.00-1000 ng/g.The detection limits of three known TPM's metabolites were within the range of 3.20-4.90 ng/g.Relative standard deviations(RSDs) of intra-day and inter-day precisions were less than 18.3%,which showed perfect reproducibility.The method was successfully applied to monitoring TPM's BZD metabolites in celery cabbage sprayed with TPM and the concentration versus time curves of TPM's metabolites in celery cabbage were plotted.This method is expected to be used to monitor BZD residues in various fruits and vegetables.
文摘In this study, forty celery cultivars introduced from different regions of China were used as experimental materials to verify and analyze the practicability of RAPD technology in the identification of celery cuhivars. The results showed that RAPD technology could distinguish accurately the genetic relationship among various celery cultivars as a simple and ideal DNA molecular marker technology suitable for genetic relationship analysis. To be specific, 13 RAPD primers with clear amplified bands and significantly different number of amplified bands were screened, which provided basis for the identification of genetic relationship among different celery cultivars.
基金the earmarked fund for Beijing Innovation Consortium of Agriculture Research System(Grant No.BAIC-2019)Key Laboratory of Biology and Genetic Improvement of Horticultural Crops,Ministry of Agriculture,P.R.China,and Science and Technology Innovation Program of the Chinese Academy of Agricultural Sciences(Grant No.CAAS-ASTIPIVFCAAS).
文摘Pectobacterium carotovorum is the causal agent of bacterial soft rot in a wide range of vegetable host species.Once P.carotovorum infects the plant,the spread of the disease is difficult to control.In this study,a rapid and sensitive method based on loop-mediated isothermal amplification(LAMP)was developed for detecting P.carotovorum in celery with soft rot using a primer set designed from the pmrA conserved sequence of P.carotovorum.The specificity of the LAMP primer set for P.carotovorum was extensively validated on both P.carotovorum strains and nontarget strains.The sensitivity was 1 pg of P.carotovorum genomic DNA,which demonstrated 10 times more sensitive than the conventional PCR assay.LAMP was also used to detect P.carotovorum in bacterial suspension.The lowest detection concentration was 104 CFU·mL^−1.In addition,a LAMP assay,in conjunction with a crude DNA extraction method,was successfully performed on P.carotovorum-infected samples derived from both artificially and naturally infected plants.In summary,the LAMP assay established in this study constitutes a simple,sensitive,and rapid method for the detection of P.carotovorum,and has potential application in the control of celery soft rot disease through early detection.