The physiological mechanism of maintaining the green colour of pak choy leaves (Brassicarapa var chinensis) with heat-shock treatment was studied. Chlorophyll in the outerleaves of pak choy degraded rapidly during sto...The physiological mechanism of maintaining the green colour of pak choy leaves (Brassicarapa var chinensis) with heat-shock treatment was studied. Chlorophyll in the outerleaves of pak choy degraded rapidly during storage at ambient temperature (20±2℃), aslight yellow appeared. Heat-shock treatment (46-50℃) had a mild effect on maintainingthe green colour of outer leaves. Normal chlorophyll degradation was associated with abinding of chlorophyll with chlorophyll-binding-protein preceding chlorophyll breakdown.Heat-shock treatment was found to reduce the binding-capacity between chlorophyll-binding-protein and chlorophyll. In the chlorophyll degradation pathway, pheide dioxygenasewas synthesized during leaf senescence which was considered to be a key enzyme inchlorophyll degradation. Activity of this enzyme was reduced following heat-shocktreatment, which might explain the observed reduction in chlorophyll breakdown. Twogroups of heat-shock proteins were detected in treated leaves, the first group containingproteins from 54KDa to 74Kda, and the second group contained proteins from 15KDa to29KDa. Heat-shock treatment was also found to retard the decline of glucose and fructose(the main energy substrates) of outer leaves.展开更多
Melatonin(MT)is a low molecular weight compound with multiple biological functions in plants.It is known to delay leaf senescence in various species.However,no data are available on the MT signaling pathway in posthar...Melatonin(MT)is a low molecular weight compound with multiple biological functions in plants.It is known to delay leaf senescence in various species.However,no data are available on the MT signaling pathway in postharvest vegetables.This study demonstrates that MT increases cGMP concentration and the expression of the cGMP synthesis gene BcGC1 in pak choi.The c GMP inhibitor LY83583 destroys effect of MT delaying the leaf senescence.LY83583 also prevents MT treatment from reducing the expression of chlorophyll metabolism-related genes(BcNYC1,BcNOL,BcPPH1/2,BcSGR1/2,and BcPAO)and senescence genes(BcSAG12 and BcSAG21).It also inhibits MT from reducing the activity of the key chlorophyll catabolism enzymes Mg-dechelatase,pheophytinase,and pheide a oxygenase.Thus,the ability of MT to maintain high levels of chlorophyll metabolites is also destroyed.The Arabidopsis c GMP synthetic gene mutant atgc1 was used to confirm that delayed leaf senescence caused by MT is mediated,at least in part,by the second messenger c GMP.展开更多
To evaluate the supplementary blue light intensity on growth and health-promoting compounds in pak choi（Brassica campestris ssp.chinensis var.communis）,four blue light intensity treatments（T0,T50,T100 and T150 indi...To evaluate the supplementary blue light intensity on growth and health-promoting compounds in pak choi（Brassica campestris ssp.chinensis var.communis）,four blue light intensity treatments（T0,T50,T100 and T150 indicate 0,50,100,and 150μmol m^（-2） s^（-1）,respectively）were applied 10 days before harvest under greenhouse conditions.Both of cultivars（greenand red-leaf pak choi）under T50 had the highest yield,content of chlorophyll and sugars.With light intensity increasing,antioxidant compounds（vitamin C and carotenoids）significantly increased,while nitrate content showed an opposite trend.The health-promoting compounds（phenolics,flavonoids,anthocyanins,and glucosinolates）were significantly higher under supplementary light treatment than T0,so as the antioxidant capacity（2,2-diphenyl-1-picrylhydrazyl and ferric-reducing antioxidant power）.The species-specific differences in photosynthetic pigment and health-promoting compounds was found in green-and red-leaf pak choi.T50 treatment could be used for yield improvement,whereas T100 treatment could be applied for quality improvement.Results showed that blue light intensity can regulate the accumulation of biomass,morphology and health-promoting compounds in pak choi under greenhouse conditions.展开更多
Pak choi is a low-temperature vernalized plant that readily undergoes premature bolting during spring, but little is known about the governing molecular regulation of vernalization. In order to enhance our understandi...Pak choi is a low-temperature vernalized plant that readily undergoes premature bolting during spring, but little is known about the governing molecular regulation of vernalization. In order to enhance our understanding of mechanism about premature bolting, we discussed the relationship between auxin(indole-3-acetic acid, IAA) and flowering of pak choi. During vernalization, hormone metabolism is an important regulatory pathway, and IAA plays a specific role. IAA metabolism has been studied in Arabidopsis thaliana and other plants, but not in pak choi. In this paper, the IAA content in pak choi shoot apices during vernalization and different growth stages was compared. The IAA content decreased significantly after low-temperature treatment(4 °C) and then increased rapidly during vegetative growth. During floral bud initiation,the IAA content decreased rapidly and was the lowest. Expressions of genes encoding key IAA metabolic enzymes were analyzed, and a major synthetase-encoding gene was downregulated, while a key degrading enzyme-encoding gene was upregulated during each comparison period,resulting in decreased IAA content. Expressions of four genes(Bra034975, Bra030246, Bra012239 and Bra040296) were consistent with changes in the IAA content. The functions of differentially expressed genes(DEGs) were analyzed, and 15 DEGs were found to be related to IAA metabolism.The findings illuminated the molecular mechanism regulating IAA content during vernalization in pak choi.展开更多
In the present study, a pot experiment was carded out to investigate the effects of a composite soil amendment at different levels （0, 600, 900 and 1 200 mg/kg） on the soil organic matter content, pH, Pb uptake and ...In the present study, a pot experiment was carded out to investigate the effects of a composite soil amendment at different levels （0, 600, 900 and 1 200 mg/kg） on the soil organic matter content, pH, Pb uptake and nutritional quality of pak choi （Brassica rapa L. Chinensis Group） grown in the soils contaminated by four levels （800, 1 200, 1 600 and 2 000 mg/kg） of Pb. The results showed that 900 mg/kg soil amendment increased the soil organic matter content by 24.19%- 60.00%, but had no significant influence on soil pH. Comparing with control （without amendment application）, the security and nutritional quality of pak choi were obviously improved by applying the soil amendment. In detail, 900 mg/kg soil amendment improved the content of Vc of pak choi growing in 800, 1 200, 1 600 and 2 000 mg/kg Pb-contaminated soils by 13.27%-69.30%, the content of soluble sugar by 54.17%- 87.50%, the dry matter weight by 28.36%-33.39%, and decreased the content of Pb by 19.11%-35.72% and the content of crude fiber by 20.83%-31.03%, respectively. These data indicated that the composite amendment can be used for the in situ repair of Pb-contaminated soils, and the recommended dosage is 900 mg/kg.展开更多
Melatonin(MT)is a low molecular weight compound with a wide variety of biological functions in plants.It is known to delay senescence in various fruits and vegetables.This study demonstrates that MT(100μmol/L)delayed...Melatonin(MT)is a low molecular weight compound with a wide variety of biological functions in plants.It is known to delay senescence in various fruits and vegetables.This study demonstrates that MT(100μmol/L)delayed the senescence of pak choi stored at 20°C.A total of 1121 differentially expressed genes(DEGs)were identified in an MT-treated group in comparison to untreated pak choi.Analysis of DEGs revealed that MT-induced delay in senescence involved reduction in the expression of chlorophyll metabolism genes and regulation of the expression of hormone-related genes and leaf senescence-related transcription factors.MT decreased the activity of chlorophyll metabolism-related enzymes Mg-dechelatase,pheophytinase,and pheide a oxygenase,decreased the concentrations of abscisic acid and jasmonic acid,and increased auxin concentration.MT delayed the impact of senescence-related transcription factors BcNAC41 and BcNAC87 on tobacco leaf senescence.This study provides an insight into the molecular mechanisms of MT-induced delay of postharvest senescence in pak choi and confirms its potential as a preservation technique.展开更多
Glucosinolates(GSs) play an important role in plant defense systems and human nutrition.We investigated the content and composition of GSs in the shoots and roots of seven cultivars of pak choi.We found that 'Si Y...Glucosinolates(GSs) play an important role in plant defense systems and human nutrition.We investigated the content and composition of GSs in the shoots and roots of seven cultivars of pak choi.We found that 'Si Yue Man' had the highest total and aliphatic GS contents in the shoots and the highest benzenic GS content in the roots,'Shanghai Qing' contained the highest amounts of benzenic and total GS contents in the roots,while 'Nanjing Zhong Gan Bai' had the lowest benzenic,indole,and total GS contents in both the shoots and roots.Therefore,the 'Si Yue Man' cultivar appears to be a good candidate for future breeding.Variation between the shoots and roots was also examined,and a significant correlation among the total,aliphatic,and some individual GSs was found,which is of value in agricultural breeding.GS concentrations of the leaf,petiole,and root increased dramatically during the period of rapid growth of the dry matter of the plant 10 to 20 d after transplantation,reaching peak values on Day 20 and decreasing on Day 25.We conclude that the pak choi should be harvested and consumed from 20 to 25 d after transplantation to take advantages of the high GS content in the plant.展开更多
文摘The physiological mechanism of maintaining the green colour of pak choy leaves (Brassicarapa var chinensis) with heat-shock treatment was studied. Chlorophyll in the outerleaves of pak choy degraded rapidly during storage at ambient temperature (20±2℃), aslight yellow appeared. Heat-shock treatment (46-50℃) had a mild effect on maintainingthe green colour of outer leaves. Normal chlorophyll degradation was associated with abinding of chlorophyll with chlorophyll-binding-protein preceding chlorophyll breakdown.Heat-shock treatment was found to reduce the binding-capacity between chlorophyll-binding-protein and chlorophyll. In the chlorophyll degradation pathway, pheide dioxygenasewas synthesized during leaf senescence which was considered to be a key enzyme inchlorophyll degradation. Activity of this enzyme was reduced following heat-shocktreatment, which might explain the observed reduction in chlorophyll breakdown. Twogroups of heat-shock proteins were detected in treated leaves, the first group containingproteins from 54KDa to 74Kda, and the second group contained proteins from 15KDa to29KDa. Heat-shock treatment was also found to retard the decline of glucose and fructose(the main energy substrates) of outer leaves.
基金supported by the National Natural Science Foundation of China(Grant No.32001451)Jiangsu Agriculture Science and Technology Innovation Fund[Grant No.CX(20)1008]。
文摘Melatonin(MT)is a low molecular weight compound with multiple biological functions in plants.It is known to delay leaf senescence in various species.However,no data are available on the MT signaling pathway in postharvest vegetables.This study demonstrates that MT increases cGMP concentration and the expression of the cGMP synthesis gene BcGC1 in pak choi.The c GMP inhibitor LY83583 destroys effect of MT delaying the leaf senescence.LY83583 also prevents MT treatment from reducing the expression of chlorophyll metabolism-related genes(BcNYC1,BcNOL,BcPPH1/2,BcSGR1/2,and BcPAO)and senescence genes(BcSAG12 and BcSAG21).It also inhibits MT from reducing the activity of the key chlorophyll catabolism enzymes Mg-dechelatase,pheophytinase,and pheide a oxygenase.Thus,the ability of MT to maintain high levels of chlorophyll metabolites is also destroyed.The Arabidopsis c GMP synthetic gene mutant atgc1 was used to confirm that delayed leaf senescence caused by MT is mediated,at least in part,by the second messenger c GMP.
基金supported by the National Key Research and Development Program of China (2017YFD0701500)the Teamwork Projects Funded by Guangdong Natural Science Foundation, China (S2013030012842)+1 种基金the Guangdong Provincial Science & Technology Project, China (2015A020209146, 2015B090903074)the Guangzhou Science & Technology Project, China (201605030005, 201704020058)
文摘To evaluate the supplementary blue light intensity on growth and health-promoting compounds in pak choi（Brassica campestris ssp.chinensis var.communis）,four blue light intensity treatments（T0,T50,T100 and T150 indicate 0,50,100,and 150μmol m^（-2） s^（-1）,respectively）were applied 10 days before harvest under greenhouse conditions.Both of cultivars（greenand red-leaf pak choi）under T50 had the highest yield,content of chlorophyll and sugars.With light intensity increasing,antioxidant compounds（vitamin C and carotenoids）significantly increased,while nitrate content showed an opposite trend.The health-promoting compounds（phenolics,flavonoids,anthocyanins,and glucosinolates）were significantly higher under supplementary light treatment than T0,so as the antioxidant capacity（2,2-diphenyl-1-picrylhydrazyl and ferric-reducing antioxidant power）.The species-specific differences in photosynthetic pigment and health-promoting compounds was found in green-and red-leaf pak choi.T50 treatment could be used for yield improvement,whereas T100 treatment could be applied for quality improvement.Results showed that blue light intensity can regulate the accumulation of biomass,morphology and health-promoting compounds in pak choi under greenhouse conditions.
基金supported by Shanxi Province Key Research and Development Program Key Projects (Grant No. 201703D211006 201703D211001-04-01)the Natural Science Foundation of Shanxi Province (Grant No. 201701D121101)
文摘Pak choi is a low-temperature vernalized plant that readily undergoes premature bolting during spring, but little is known about the governing molecular regulation of vernalization. In order to enhance our understanding of mechanism about premature bolting, we discussed the relationship between auxin(indole-3-acetic acid, IAA) and flowering of pak choi. During vernalization, hormone metabolism is an important regulatory pathway, and IAA plays a specific role. IAA metabolism has been studied in Arabidopsis thaliana and other plants, but not in pak choi. In this paper, the IAA content in pak choi shoot apices during vernalization and different growth stages was compared. The IAA content decreased significantly after low-temperature treatment(4 °C) and then increased rapidly during vegetative growth. During floral bud initiation,the IAA content decreased rapidly and was the lowest. Expressions of genes encoding key IAA metabolic enzymes were analyzed, and a major synthetase-encoding gene was downregulated, while a key degrading enzyme-encoding gene was upregulated during each comparison period,resulting in decreased IAA content. Expressions of four genes(Bra034975, Bra030246, Bra012239 and Bra040296) were consistent with changes in the IAA content. The functions of differentially expressed genes(DEGs) were analyzed, and 15 DEGs were found to be related to IAA metabolism.The findings illuminated the molecular mechanism regulating IAA content during vernalization in pak choi.
基金Supported by the Fund of Beijing Leafy Vegetables Innovation Team of Modren Agroindustry Technology Research System(BAIC07-2016)the Fund of Beijing Municipal Commission of Rural Affairs(20120129)~~
文摘In the present study, a pot experiment was carded out to investigate the effects of a composite soil amendment at different levels （0, 600, 900 and 1 200 mg/kg） on the soil organic matter content, pH, Pb uptake and nutritional quality of pak choi （Brassica rapa L. Chinensis Group） grown in the soils contaminated by four levels （800, 1 200, 1 600 and 2 000 mg/kg） of Pb. The results showed that 900 mg/kg soil amendment increased the soil organic matter content by 24.19%- 60.00%, but had no significant influence on soil pH. Comparing with control （without amendment application）, the security and nutritional quality of pak choi were obviously improved by applying the soil amendment. In detail, 900 mg/kg soil amendment improved the content of Vc of pak choi growing in 800, 1 200, 1 600 and 2 000 mg/kg Pb-contaminated soils by 13.27%-69.30%, the content of soluble sugar by 54.17%- 87.50%, the dry matter weight by 28.36%-33.39%, and decreased the content of Pb by 19.11%-35.72% and the content of crude fiber by 20.83%-31.03%, respectively. These data indicated that the composite amendment can be used for the in situ repair of Pb-contaminated soils, and the recommended dosage is 900 mg/kg.
基金the National Natural Science Foundation of China(No.32001451)the Key and General Programs of Modern Agriculture in Jiangsu Province(No.BE2022368),China.
文摘Melatonin(MT)is a low molecular weight compound with a wide variety of biological functions in plants.It is known to delay senescence in various fruits and vegetables.This study demonstrates that MT(100μmol/L)delayed the senescence of pak choi stored at 20°C.A total of 1121 differentially expressed genes(DEGs)were identified in an MT-treated group in comparison to untreated pak choi.Analysis of DEGs revealed that MT-induced delay in senescence involved reduction in the expression of chlorophyll metabolism genes and regulation of the expression of hormone-related genes and leaf senescence-related transcription factors.MT decreased the activity of chlorophyll metabolism-related enzymes Mg-dechelatase,pheophytinase,and pheide a oxygenase,decreased the concentrations of abscisic acid and jasmonic acid,and increased auxin concentration.MT delayed the impact of senescence-related transcription factors BcNAC41 and BcNAC87 on tobacco leaf senescence.This study provides an insight into the molecular mechanisms of MT-induced delay of postharvest senescence in pak choi and confirms its potential as a preservation technique.
基金Project supported by the National Natural Science Foundation of China (Nos.30871718 and 31201620)the Zhejiang Provincial Natural Science Foundation of China(No.R3080360)the Fund for Zhejiang Higher School Innovative Research Team(No.T200916),China
文摘Glucosinolates(GSs) play an important role in plant defense systems and human nutrition.We investigated the content and composition of GSs in the shoots and roots of seven cultivars of pak choi.We found that 'Si Yue Man' had the highest total and aliphatic GS contents in the shoots and the highest benzenic GS content in the roots,'Shanghai Qing' contained the highest amounts of benzenic and total GS contents in the roots,while 'Nanjing Zhong Gan Bai' had the lowest benzenic,indole,and total GS contents in both the shoots and roots.Therefore,the 'Si Yue Man' cultivar appears to be a good candidate for future breeding.Variation between the shoots and roots was also examined,and a significant correlation among the total,aliphatic,and some individual GSs was found,which is of value in agricultural breeding.GS concentrations of the leaf,petiole,and root increased dramatically during the period of rapid growth of the dry matter of the plant 10 to 20 d after transplantation,reaching peak values on Day 20 and decreasing on Day 25.We conclude that the pak choi should be harvested and consumed from 20 to 25 d after transplantation to take advantages of the high GS content in the plant.
