In order to completely evaluate ammonia emission from greenhouse vegetable fields,crop canopy absorption should not be neglected.The foliar uptake of NH3 applied at two growth stages and the subsequent 15N-labeled N t...In order to completely evaluate ammonia emission from greenhouse vegetable fields,crop canopy absorption should not be neglected.The foliar uptake of NH3 applied at two growth stages and the subsequent 15N-labeled N translocation to other plant components were investigated under greenhouse conditions using chambers covered with the soil of a tomato field.Treatments comprised three NH3-N application rates(70,140,and 210 mg/plot) using 15N-labeled ammonium sulfate.Plants were harvested immediately after exposure for 24 h,and the total N concentrations and 15N/14 N ratios were determined.With increased NH3 concentration,total 15NH3-N absorption increased considerably,whereas the applied 15NH3-N uptake decreased gradually.The tomato plants absorbed 33-38% and 24-31% of the 15NH3-N generated at the anthesis and fruit growth stages,respectively.A total of 71-80% of the recovered NH3 was observed in the leaves and 20-30% of the recovered NH3 was remobilized to other components.Among them,an average of 10% of the absorbed 15NH3-N was transferred into the tomato fruits.All these results indicated the potential of the tested tomatoes for the foliar uptake of atmospheric 15NH3 and the distribution of 15N-labeled vegetative N among different plant components.The results are of great importance for the complete evaluation of nitrogen use efficiency in the greenhouse tomato fields.展开更多
Bacillus subtilis(B. subtilis) and Pseudomonas fluorescens(P. fluorescens) are two of the most important plant growth promoting rhizobacteria(PGPR) in agriculture. An in situ trial was conducted on greenhouse tomato(L...Bacillus subtilis(B. subtilis) and Pseudomonas fluorescens(P. fluorescens) are two of the most important plant growth promoting rhizobacteria(PGPR) in agriculture. An in situ trial was conducted on greenhouse tomato(Lycopersicum esculentum Mill.) to examine the effect of two bacterial strains, Bacillus subtilis(CGMCC 1.3343) and Pseudomonas fluorescens(CGMCC 1.1802), on tomato growth, gray mold disease control, catabolic and genetic microbial features of indigenous rhizosphere bacteria under lownitrogen conditions. A commercial inoculant(ETS) was also tested as a comparison. Both B. subtilis and P. fluorescens promoted growth and biomass of seedlings, while only B. subtilis was effi cient in reducing gray mold incidence in greenhouse tomato. The two bacterial strains could colonization in tomato rhizosphere soil at the end of experiment(10 days after the last inoculation). Different AWCD trends and DGGE patterns were got in different bacterial treatments; however, analyses of microbial diversities showed that indigenous soil microbes did not seem to have signifi cant differences at either the catabolic or genetic level among treatments. ETS, as a commercial microbial agent, promoted plant growth and gave a higher microbial diversity in rhizosphere soil.展开更多
Sucrose is the main constituent of assimilation transport from source to sink.In order to study the transport mechanism of sucrose,the sucrose at stem was taken as a research object and the sucrose flow field in tomat...Sucrose is the main constituent of assimilation transport from source to sink.In order to study the transport mechanism of sucrose,the sucrose at stem was taken as a research object and the sucrose flow field in tomato stem was analyzed using CFD ANSYS FLUENT simulation.The results showed that the sucrose pressure distribution was lower at bottom node and higher at middle node.The velocity of sucrose at different nodes was higher at the bottom node and lower at middle node and assimilation flow direction of the first,second,and third leaf from the bottom was towards the roots.The result of verification experiment showed that sucrose content measured at different nodes was higher at middle node than that of bottom node.Results of this study confirmed that ANASYS FLUENT can better simulate sucrose migration in greenhouse tomato stem.This study provides a new method for studying the partitioning mechanism of tomato assimilates in greenhouse.展开更多
A pot experiment was conducted to investigate the effects of different water and nitrogen supply amounts on the comprehensive assessment of tomato fruit quality and root growth parameters under alternate partial root-...A pot experiment was conducted to investigate the effects of different water and nitrogen supply amounts on the comprehensive assessment of tomato fruit quality and root growth parameters under alternate partial root-zone irrigation.Three upper irrigation limitations(i.e.70%(W1),80%(W2)and 90%(W3)of field capacity,respectively)and three N-fertilizer levels(i.e.0.18(N1),0.30(N2)and 0.42(N3)g/kg soil,respectively)were arranged with a randomized complete block design,and alternate partial root-zone irrigation method was applied.Results showed that fruit yields under deficit irrigation(W1 and W2)were decreased by 6.9%and 2.0%respectively compared with W3 under N1 level.Yields of tomato under W1N1 and W1N2 combinations were also reduced by 10.3%and 7.2%,respectively compared with W1N3 combination.Root dry weight,root length,root surface area and root volume were all increased in W1N2 treatment.According to two-way ANOVA,the root parameters except root dry weight,were extremely sensitive to water,nitrogen and the cross effect of the two factors.TSS(total soluble solids),SS(soluble sugars)and OA(organic acid)in the fruits increased with the decrease in irrigation water,OA and NC reduced with decreasing amount of nitrogen.Moreover,within an appropriate range,as more irrigation water and nitrogen were applied,the higher VC(vitamin C)and lycopene contents were identified in the fruits.Eventually,the combinational evaluation method(i.e.entropy method and gray relational analysis)showed that W2N2 ranked highest in comprehensive fruit quality.Therefore,considering the tradeoff between fruit comprehensive quality and yields,upper irrigation limitation of 80%θf and N-fertilizer of 0.30 g/kg soil with alternate partial root-zone irrigation was the optimal cultivation strategy for the greenhouse tomato in autumn-winter season in northwest China.展开更多
基金funded by the National Key Research and Development Program of China (2017YFD0200106)
文摘In order to completely evaluate ammonia emission from greenhouse vegetable fields,crop canopy absorption should not be neglected.The foliar uptake of NH3 applied at two growth stages and the subsequent 15N-labeled N translocation to other plant components were investigated under greenhouse conditions using chambers covered with the soil of a tomato field.Treatments comprised three NH3-N application rates(70,140,and 210 mg/plot) using 15N-labeled ammonium sulfate.Plants were harvested immediately after exposure for 24 h,and the total N concentrations and 15N/14 N ratios were determined.With increased NH3 concentration,total 15NH3-N absorption increased considerably,whereas the applied 15NH3-N uptake decreased gradually.The tomato plants absorbed 33-38% and 24-31% of the 15NH3-N generated at the anthesis and fruit growth stages,respectively.A total of 71-80% of the recovered NH3 was observed in the leaves and 20-30% of the recovered NH3 was remobilized to other components.Among them,an average of 10% of the absorbed 15NH3-N was transferred into the tomato fruits.All these results indicated the potential of the tested tomatoes for the foliar uptake of atmospheric 15NH3 and the distribution of 15N-labeled vegetative N among different plant components.The results are of great importance for the complete evaluation of nitrogen use efficiency in the greenhouse tomato fields.
基金Supported by the National High-tech Research and Development Program of China(2013AA102903)
文摘Bacillus subtilis(B. subtilis) and Pseudomonas fluorescens(P. fluorescens) are two of the most important plant growth promoting rhizobacteria(PGPR) in agriculture. An in situ trial was conducted on greenhouse tomato(Lycopersicum esculentum Mill.) to examine the effect of two bacterial strains, Bacillus subtilis(CGMCC 1.3343) and Pseudomonas fluorescens(CGMCC 1.1802), on tomato growth, gray mold disease control, catabolic and genetic microbial features of indigenous rhizosphere bacteria under lownitrogen conditions. A commercial inoculant(ETS) was also tested as a comparison. Both B. subtilis and P. fluorescens promoted growth and biomass of seedlings, while only B. subtilis was effi cient in reducing gray mold incidence in greenhouse tomato. The two bacterial strains could colonization in tomato rhizosphere soil at the end of experiment(10 days after the last inoculation). Different AWCD trends and DGGE patterns were got in different bacterial treatments; however, analyses of microbial diversities showed that indigenous soil microbes did not seem to have signifi cant differences at either the catabolic or genetic level among treatments. ETS, as a commercial microbial agent, promoted plant growth and gave a higher microbial diversity in rhizosphere soil.
基金the senior personnel of Jiangsu University foundation(Grant No.13JDG31)the priority academic program development of Jiangsu Higher Education Institutions(Grant No.2014037).
文摘Sucrose is the main constituent of assimilation transport from source to sink.In order to study the transport mechanism of sucrose,the sucrose at stem was taken as a research object and the sucrose flow field in tomato stem was analyzed using CFD ANSYS FLUENT simulation.The results showed that the sucrose pressure distribution was lower at bottom node and higher at middle node.The velocity of sucrose at different nodes was higher at the bottom node and lower at middle node and assimilation flow direction of the first,second,and third leaf from the bottom was towards the roots.The result of verification experiment showed that sucrose content measured at different nodes was higher at middle node than that of bottom node.Results of this study confirmed that ANASYS FLUENT can better simulate sucrose migration in greenhouse tomato stem.This study provides a new method for studying the partitioning mechanism of tomato assimilates in greenhouse.
基金support from the National High-Tech 863 Project of China(2013AA103004)the program of Water Conservancy Science and Technology Plan of shaanxi Province(2014slkj-17).
文摘A pot experiment was conducted to investigate the effects of different water and nitrogen supply amounts on the comprehensive assessment of tomato fruit quality and root growth parameters under alternate partial root-zone irrigation.Three upper irrigation limitations(i.e.70%(W1),80%(W2)and 90%(W3)of field capacity,respectively)and three N-fertilizer levels(i.e.0.18(N1),0.30(N2)and 0.42(N3)g/kg soil,respectively)were arranged with a randomized complete block design,and alternate partial root-zone irrigation method was applied.Results showed that fruit yields under deficit irrigation(W1 and W2)were decreased by 6.9%and 2.0%respectively compared with W3 under N1 level.Yields of tomato under W1N1 and W1N2 combinations were also reduced by 10.3%and 7.2%,respectively compared with W1N3 combination.Root dry weight,root length,root surface area and root volume were all increased in W1N2 treatment.According to two-way ANOVA,the root parameters except root dry weight,were extremely sensitive to water,nitrogen and the cross effect of the two factors.TSS(total soluble solids),SS(soluble sugars)and OA(organic acid)in the fruits increased with the decrease in irrigation water,OA and NC reduced with decreasing amount of nitrogen.Moreover,within an appropriate range,as more irrigation water and nitrogen were applied,the higher VC(vitamin C)and lycopene contents were identified in the fruits.Eventually,the combinational evaluation method(i.e.entropy method and gray relational analysis)showed that W2N2 ranked highest in comprehensive fruit quality.Therefore,considering the tradeoff between fruit comprehensive quality and yields,upper irrigation limitation of 80%θf and N-fertilizer of 0.30 g/kg soil with alternate partial root-zone irrigation was the optimal cultivation strategy for the greenhouse tomato in autumn-winter season in northwest China.
