Recently developed ‘super’ rice cultivars with greater yield potentials often suffer from the problem of poor grain filling, especially in inferior spikelets. Here, we studied the activities of enzymes related to st...Recently developed ‘super’ rice cultivars with greater yield potentials often suffer from the problem of poor grain filling, especially in inferior spikelets. Here, we studied the activities of enzymes related to starch metabolism in rice stems and grains, and the microstructures related to carbohydrate accumulation and transportation to investigate the effects of different water regimes on grain filling. Two ‘super’ rice cultivars were grown under two irrigation regimes of well-watered(WW) and alternate wetting and moderate soil drying(AWMD). Compared with the WW treatment,the activities of ADP glucose pyrophosphorylase(AGPase), starch synthase(StSase) and starch branching enzyme(SBE), and the accumulation of non-structural carbohydrates(NSCs) in the stems before heading were significantly improved, and more starch granules were stored in the stems in the AWMD treatment. After heading, the activities of α-amylase, β-amylase, sucrose phosphate synthase(SPS) and sucrose synthase in the synthetic direction(SSs)were increased in the stems to promote the remobilization of NSCs for grain filling under AWMD. During grain filling, the enzymatic activities of sucrose synthase in the cleavage direction(SSc), AGPase, StSase and SBE in the inferior spikelets were increased, which promoted grain filling, especially for the inferior spikelets under AWMD.However, there were no significant differences in vascular microstructures. The grain yield and grain weight could be improved by 13.1 and 7.5%, respectively, by optimizing of the irrigation regime. We concluded that the low activities of key enzymes in carbon metabolism is the key limitation for the poor grain filling, as opposed to the vascular microstructures, and AWMD can increase the amount of NSC accumulation in the stems before heading, improve the utilization rate of NSCs after heading, and increase the grain filling, especially in the inferior spikelets, by altering the activities of key enzymes in carbon metabolism.展开更多
Modern rice production faces the dual challenges of increasing grain yields while reducing inputs of chemical fertilizer.However,the disequilibrium between the nitrogen(N)supplement from the soil and the demand for N ...Modern rice production faces the dual challenges of increasing grain yields while reducing inputs of chemical fertilizer.However,the disequilibrium between the nitrogen(N)supplement from the soil and the demand for N of plants is a serious obstacle to achieving these goals.Plant-based diagnosis can help farmers make better choices regarding the timing and amount of topdressing N fertilizer.Our objective was to evaluate a non-destructive assessment of rice N demands based on the relative SPAD value(RSPAD)due to leaf positional differences.In this study,two field experiments were conducted,including a field experiment of different N rates(Exp.I)and an experiment to evaluate the new strategy of nitrogen-split application based on RSPAD(Exp.II).The results showed that higher N inputs significantly increased grain yield in modern high yielding super rice,but at the expense of lower nitrogen use efficiency(NUE).The N nutrition index(NNI)can adequately differentiate situations of excessive,optimal,and insufficient N nutrition in rice,and the optimal N rate for modern high yielding rice is higher than conventional cultivars.The RSPAD is calculated as the SPAD value of the top fully expanded leaf vs.the value of the third leaf,which takes into account the non-uniform N distribution within a canopy.The RSPAD can be used as an indicator for higher yield and NUE,and guide better management of N fertilizer application.Furthermore,we developed a new strategy of nitrogen-split application based on RSPAD,in which the N rate was reduced by 18.7%,yield was increased by 1.7%,and the agronomic N use efficiency was increased by 27.8%,when compared with standard farmers'practices.This strategy of N fertilization shows great potential for ensuring high yielding and improving NUE at lower N inputs.展开更多
Integrative cultivation practices(ICPs)are essential for enhancing cereal yield and resource use efficiency.However,the effects of ICP on the rhizosphere environment and roots of paddy rice are still poorly understood...Integrative cultivation practices(ICPs)are essential for enhancing cereal yield and resource use efficiency.However,the effects of ICP on the rhizosphere environment and roots of paddy rice are still poorly understood.In this study,four rice varieties were produced in the field.Each variety was treated with six different cultivation techniques,including zero nitrogen application(0 N),local farmers’practice(LFP),nitrogen reduction(NR),and three progressive ICP techniques comprised of enhanced fertilizer N practice and increased plant density(ICP1),a treatment similar to ICP1 but with alternate wetting and moderate drying instead of continuous flooding(ICP2),and the same practices as ICP2 with the application of organic fertilizer(ICP3).The ICPs had greater grain production and nitrogen use efficiency than the other three methods.Root length,dry weight,root diameter,activity of root oxidation,root bleeding rate,zeatin and zeatin riboside compositions,and total organic acids in root exudates were elevated with the introduction of the successive cultivation practices.ICPs enhanced nitrate nitrogen,the activities of urease and invertase,and the diversity of microbes(bacteria)in rhizosphere and non-rhizosphere soil,while reducing the ammonium nitrogen content.The nutrient contents(ammonium nitrogen,total nitrogen,total potassium,total phosphorus,nitrate,and available phosphorus)and urease activity in rhizosphere soil were reduced in all treatments in comparison with the non-rhizosphere soil,but the invertase activity and bacterial diversity were greater.The main root morphology and physiology,and the ammonium nitrogen contents in rhizosphere soil at the primary stages were closely correlated with grain yield and internal nitrogen use efficiency.These findings suggest that the coordinated enhancement of the root system and the environment of the rhizosphere under integrative cultivation approaches may lead to higher rice production.展开更多
Leaf-color modification can affect canopy photosynthesis,with potential effects on rice yield and yield components.Modulating source-sink relationships through crop management is often used to improve crop productivit...Leaf-color modification can affect canopy photosynthesis,with potential effects on rice yield and yield components.Modulating source-sink relationships through crop management is often used to improve crop productivity.This study investigated whether and how modifying leaf color alters source-sink relationships and whether current crop cultivation practices remain applicable for leaf-color modified genotypes.Periodically collected data of total biomass and nitrogen(N)accumulation in rice genotypes of four genetic backgrounds and their leaf-color modified variants(greener or yellower)were analyzed,using a recently established modelling method to quantify the source-sink(im)balance during grain filling.Among all leaf-color variants,only one yellower-leaf variant showed a higher source capacity than its normal genotype.This was associated with greater post-flowering N-uptake that prolonged the functional leaf-N duration,and this greater post-flowering N-uptake was possible because of reduced pre-flowering N-uptake.A density experiment showed that current management practices(insufficient planting density accompanied by abundant N application)are unsuitable for the yellower-leaf genotype,ultimately limiting its yield potential.Leaf-color modification affects source-sink relationships by regulating the N trade-off between pre-and post-flowering uptake,as well as N translocation between source and sink organs.To best exploit leaf-color modification for improving crop productivity,adjustments of crop management practices are required.展开更多
Phosphorus use efficiency(PUE)can be improved through cultivation techniques and breeding.However,little is known about rice(Oryza sativa L.)agronomic and physiological traits associated with high PUE.We characterized...Phosphorus use efficiency(PUE)can be improved through cultivation techniques and breeding.However,little is known about rice(Oryza sativa L.)agronomic and physiological traits associated with high PUE.We characterized the agronomic and physiological traits of rice varieties with different tolerances to low phosphorus in nutrient solution.Two varieties with strong tolerance to low phosphorus(STVs)and two with weak tolerance(WTVs)were grown at normal(NP,control)and low phosphorus(LP,1/20 of NP)concentrations.Plants grown at LP produced significantly lower grain yield than those grown at NP.WTVs yields were lower than STVs yields.Compared to NP,LP significantly increased phosphorus translocation efficiency(PTE),internal phosphorus efficiency(IPE)and phosphorus harvest index(PHI).Under the LP condition,PTE and IPE were higher for STVs than for WTVs.LP also reduced tiller number,shoot biomass,leaf area index(LAI),leaf photosynthetic rate,and mean root diameter of both kinds of varieties at the main growth stages,but to a lower extent in STVs.LP significantly increased the number of productive tillers,root biomass,root-shoot ratio,root bleeding rate,and root acid phosphatase(RAP)activity.Total root length,root oxidation activity(ROA),and root total and active absorbing surface areas for STVs were significantly increased under LP,whereas the opposite responses were observed for WTVs.Total root length,ROA,root bleeding rate,root active absorbing surface area,and RAP activity were positively and significantly correlated with grain yield,PTE,and IPE.These results suggest that the tolerance of rice varieties to a low-phosphorus growth condition is closely associated with root growth with higher biomass and activity.展开更多
Root morphology and physiology influence aboveground growth and yield formation in rice.However,root morphological and physiological differences among rice varieties with differing nitrogen(N)sensitivities and their r...Root morphology and physiology influence aboveground growth and yield formation in rice.However,root morphological and physiological differences among rice varieties with differing nitrogen(N)sensitivities and their relationship with grain yield are still unclear.In this study,rice varieties differing in N sensitivity over many years of experiments were used.A field experiment with multiple N rates(0,90,180,270,and 360 kg ha^(-1))was conducted to elucidate the effects of N application on root morphology,root physiology,and grain yield.A pot experiment with root excision and exogenous application of 6-benzyladenine(6-BA)at heading stage was used to further verify the above effects.The findings revealed that(1)under the same N application rate,N-insensitive varieties(NIV)had relatively large root biomass(root dry weight,length,and number).Grain yield was associated with root biomass in NIV.The oxidation activity and zeatin(Z)+zeatin riboside(ZR)contents in roots obviously and positively correlated with grain yield in N-sensitive varieties(NSV),and accounted for its higher grain yield than that of NIV at lower N application rates(90 and 180 kg ha^(-1)).(2)The root dry weight required for equal grain yield of NIV was greater than that of NSV.Excision of 1/10 and 1/8 of roots at heading stage had no discernible effect on the yield of Liangyoupeijiu(NIV),and it significantly reduced yield by 11.5%and 21.3%in Tianyouhuazhan(NSV),respectively,compared to the treatment without root excision.The decrease of filled kernels and grain weight after root excision was the primary cause for the yield reduction.Root excision and exogenous 6-BA application after root excision had little influence on the root activity of NIV.The oxidation activity and Z+ZR contents in roots of NSV decreased under root excision,and the increase in the proportion of excised roots aggravated these effects.The application of exogenous 6-BA increased the root activity of NSV and increased filled kernels and grain weight,thereby reducing yield loss after root excision.Thus,the root biomass of NIV was large,and there may be a phenomenon of"root growth redundancy."Vigorous root activity was an essential feature of NSV.Selecting rice varieties with high root activity or increasing root activity by cultivation measures could lead to higher grain yield under lower N application rates.展开更多
While the yield potential of rice has increased but little is known about the impact of breeding on grain quality, especially under different levels of N availability. In order to investigate the integrated effects of...While the yield potential of rice has increased but little is known about the impact of breeding on grain quality, especially under different levels of N availability. In order to investigate the integrated effects of breeding and N levels on rice quality 12 japonica rice cultivars bred in the past60 years in the Yangtze River Basin were used with three levels of N: 0 kg N ha-1, 240 kg N ha-1,and 360 kg N ha-1. During the period, milling quality(brown rice percentage, milled rice percentage, and head rice percentage), appearance quality(chalky kernels percentage, chalky size, and chalkiness), and eating and cooking quality(amylose content, gel consistency, peak viscosity, breakdown, and setback) were significantly improved, but the nutritive value of the grain has declined due to a reduction in protein content. Micronutrients, such as Cu, Mg, and S contents, were decreased, and Fe, Mn, Zn, Na, Ca, K, P, B contents were increased. These changes in grain quality imply that simultaneous improvements in grain yield and grain quality are possible through selection. Overall, application of N fertilizer decreased grain quality, especially in terms of eating and cooking quality. Under higher N levels, higher protein content was the main reason for deterioration of grain quality, although lower amylose content might contribute to improving starch pasting properties. These results suggest that further improvement in grain quality will depend on both breeding and cultivation practices, especially in regard to nitrogen and water management.展开更多
In previous studies, integrative crop management (ICM) improved shoot growth and grain yield of rice (Oryza sativa L.). However, little is known about the effect of ICM on root growth and methane (CH4) emission of pad...In previous studies, integrative crop management (ICM) improved shoot growth and grain yield of rice (Oryza sativa L.). However, little is known about the effect of ICM on root growth and methane (CH4) emission of paddy rice. In this study, two rice varieties, Wuyunjing 24 and Yongyou 2640, were grown. A field experiment was conducted with three crop management treatments including zero nitrogen fertilization (0N), local farmer practice (LFP), and ICM. Root morphophysiological traits and CH4 emission from the paddy field were investigated. ICM significantly increased mean grain yield by 29.9%, with the effect attributed mainly to an increase in mean total number of spikelets by 26.4% compared to LFP. ICM increased root and shoot biomass, root length, number of roots, root oxidation activity (ROA), root bleeding rate, and root total and active absorbing surface area by respectively 24.4%, 25.7%, 17.1%, 9.3%, 18.7%, 29.5%, 12.1%, and 24.7%. The concentrations of malic, succinic, and acetic acids in root exudates were respectively 5.8%, 6.0%, and 10.5% higher in ICM than in LFP. Compared to LFP, ICM significantly decreased the rate of CH4 emission during emission peak stages and reduced total CH4 emission by 17.1%. The root morphophysiological traits were positively and significantly correlated with grain yield, whereas root length, specific root length, ROA, and root total and active absorbing surface area were negatively and significantly correlated with total CH4 emission. These results suggest that ICM could achieve the dual goals of increasing grain yield and reducing the greenhouse gas effect by improving the root morphology and physiological traits of paddy rice.展开更多
Polyamines(PAs) are important endogenous plant growth regulators responding to environmental stress and mediating many physiological processes including grain filling in cereals.This study investigated whether PAs med...Polyamines(PAs) are important endogenous plant growth regulators responding to environmental stress and mediating many physiological processes including grain filling in cereals.This study investigated whether PAs mediate the effect of post-anthesis soil drying on starch granule size distribution,starch content,and weight of superior and inferior kernels of wheat(Triticum aestivum L.).Two wheat cultivars were grown in pots.Three treatments,well-watered(WW),moderate soil drying(MD) and severe soil drying(SD),were imposed from 9 days post-anthesis until maturity.PA levels in kernels and small,medium and large granules were measured.The results showed that superior kernels had much higher free spermidine(Spd) and free spermine(Spm) concentrations,larger volumes of medium starch granules,and smaller-sized large granules than did inferior kernels under all the treatments.Compared to WW,MD significantly increased the concentrations of free Spd and free Spm,activities of soluble starch synthase and granule-bound starch synthase,volume of medium granules,and starch content and kernel weight of inferior kernels,and decreased the size of large granules.SD produced the opposite effect.Application of Spd or Spm to spikes produced effects similar to those of MD,and application of an inhibitor of Spd and Spm synthesis produced effects similar to those of SD.These results suggest that PAs mediate the effect of post-anthesis soil drying on starch biosynthesis in wheat kernels by regulating key enzymes in starch synthesis and that elevated PA levels under MD increase the volume of medium granules and kernel weight of inferior kernels.展开更多
Moutan Cortex (MC) has been demonstrated to have an inhibitive effect on inflammation and oxidative stress responses in mesangial cells in our previous study. However, little is known about the components of MC contri...Moutan Cortex (MC) has been demonstrated to have an inhibitive effect on inflammation and oxidative stress responses in mesangial cells in our previous study. However, little is known about the components of MC contributing to this benefit. In the present study, cell membrane immobilized chromatography (CMC), a fast and useful method, was presented for screening potential active components of MC. HBZY-1 cells were incubated with MC (200 μg/mL) at the optimal incubation time (90 min). HPLC-DAD analysis and LC/ESI/MS/MS were performed to distinguish the active components and identify its structural ion fragments. The results showed that eight components binding to HBZY-1 cells were mudanoside B, paeoniflorin sulfonate, paeoniflorin, tetragalloyl glucose (isomeride), hexagalloyl glucose, mudanopiside A, and paeonol. In conclusion, our established CMC might be a useful method for screening potential active components in complicated traditional Chinese medicines. These components might be associated with the efficacy of MC on prevention and treatment of diabetic nephropathy.展开更多
Permanent damage to hair cells(HCs)is the leading cause of sensory deafness.Supporting cells(SCs)are essential in the restoration of hearing in mammals because they can proliferate and differentiate to HCs.MDS1 and EV...Permanent damage to hair cells(HCs)is the leading cause of sensory deafness.Supporting cells(SCs)are essential in the restoration of hearing in mammals because they can proliferate and differentiate to HCs.MDS1 and EVI1 complex locus(MECOM)is vital in early development and cell differentiation and regulates the TGF-βsignaling pathway to adapt to pathophysiological events,such as hematopoietic proliferation,differentiation and cells death.In addition,MECOM plays an essential role in neurogenesis and craniofacial development.However,the role of MECOM in the development of cochlea and its way to regulate related signaling are not fully understood.To address this problem,this study examined the expression of MECOM during the development of cochlea and observed a significant increase of MECOM at the key point of auditory epithelial morphogenesis,indicating that MECOM may have a vital function in the formation of cochlea and regeneration of HCs.Meanwhile,we tried to explore the possible effect and potential mechanism of MECOM in SC proliferation and HC regeneration.Findings from this study indicate that overexpression of MECOM markedly increases the proliferation of SCs in the inner ear,and the expression of Smad3 and Cdkn2b related to TGF signaling is significantly down-regulated,corresponding to the overexpression of MECOM.Collectively,these data may provide an explanation of the vital function of MECOM in SC proliferation and trans-differentiation into HCs,as well as its regulation.The interaction between MECOM,Wnt,Notch and the TGF-βsignaling may provide a feasible approach to induce the regeneration of HCs.展开更多
Brassinosteroids(BRs) play crucial roles in many aspects of plant development. However, their function in spikelet differentiation and degeneration in rice(Oryza sativa L.) remains unclear. Here, we investigated the r...Brassinosteroids(BRs) play crucial roles in many aspects of plant development. However, their function in spikelet differentiation and degeneration in rice(Oryza sativa L.) remains unclear. Here, we investigated the roles of these phytohormones in spikelet development in fieldgrown rice subjected to five different nitrogen(N)fertilization treatments during panicle differentiation. BR levels and expression of genes involved in BR biosynthesis and signal transduction were measured in spikelets. Pollen fertility and the number of differentiated spikelets were closely associated with 24-epicastasterone(24-epiCS) and 28-homobrassinolide(28-homoBL) levels in spikelets.Enhanced BR biosynthesis and signal transduction, in response to N treatment, enhanced spikelet differentiation, reduced spikelet degeneration, and increased grain yield. Increases in proton-pumping ATPase activity, ATPconcentration, energy charge, and antioxidant system(AOS) levels were consistent with 24-epiCS and28-homoBL concentrations. Exogenous application of 24-epiCS or 28-homoBL on young panicles induced a marked increase in endogenous 24-epiCS or 28-homoBL levels, energy charge, AOS levels, spikelet differentiation, and panicle weight. The opposite effects were observed following treatment with a BR biosynthesis inhibitor. Our findings indicate that, in rice, BRs mediate the effects of N fertilization on spikelet development and play a role in promoting spikelet development through increasing AOS levels and energy charge during panicle development.展开更多
基金This project was finically supported by the R&D Foundation of Jiangsu Province,China(BE2022425)the National Key Research and Development Program of China(2022YFD2300304)the Priority Academic Program Development of Jiangsu Higher-Education Institutions,China(PAPD).
文摘Recently developed ‘super’ rice cultivars with greater yield potentials often suffer from the problem of poor grain filling, especially in inferior spikelets. Here, we studied the activities of enzymes related to starch metabolism in rice stems and grains, and the microstructures related to carbohydrate accumulation and transportation to investigate the effects of different water regimes on grain filling. Two ‘super’ rice cultivars were grown under two irrigation regimes of well-watered(WW) and alternate wetting and moderate soil drying(AWMD). Compared with the WW treatment,the activities of ADP glucose pyrophosphorylase(AGPase), starch synthase(StSase) and starch branching enzyme(SBE), and the accumulation of non-structural carbohydrates(NSCs) in the stems before heading were significantly improved, and more starch granules were stored in the stems in the AWMD treatment. After heading, the activities of α-amylase, β-amylase, sucrose phosphate synthase(SPS) and sucrose synthase in the synthetic direction(SSs)were increased in the stems to promote the remobilization of NSCs for grain filling under AWMD. During grain filling, the enzymatic activities of sucrose synthase in the cleavage direction(SSc), AGPase, StSase and SBE in the inferior spikelets were increased, which promoted grain filling, especially for the inferior spikelets under AWMD.However, there were no significant differences in vascular microstructures. The grain yield and grain weight could be improved by 13.1 and 7.5%, respectively, by optimizing of the irrigation regime. We concluded that the low activities of key enzymes in carbon metabolism is the key limitation for the poor grain filling, as opposed to the vascular microstructures, and AWMD can increase the amount of NSC accumulation in the stems before heading, improve the utilization rate of NSCs after heading, and increase the grain filling, especially in the inferior spikelets, by altering the activities of key enzymes in carbon metabolism.
基金finically supported by the National Key Research and Development Program of China(2022YFD2300304)the R&D Foundation of Jiangsu Province,China(BE2022425)the Priority Academic Program Development of Jiangsu Higher-Education Institutions,China(PAPD)。
文摘Modern rice production faces the dual challenges of increasing grain yields while reducing inputs of chemical fertilizer.However,the disequilibrium between the nitrogen(N)supplement from the soil and the demand for N of plants is a serious obstacle to achieving these goals.Plant-based diagnosis can help farmers make better choices regarding the timing and amount of topdressing N fertilizer.Our objective was to evaluate a non-destructive assessment of rice N demands based on the relative SPAD value(RSPAD)due to leaf positional differences.In this study,two field experiments were conducted,including a field experiment of different N rates(Exp.I)and an experiment to evaluate the new strategy of nitrogen-split application based on RSPAD(Exp.II).The results showed that higher N inputs significantly increased grain yield in modern high yielding super rice,but at the expense of lower nitrogen use efficiency(NUE).The N nutrition index(NNI)can adequately differentiate situations of excessive,optimal,and insufficient N nutrition in rice,and the optimal N rate for modern high yielding rice is higher than conventional cultivars.The RSPAD is calculated as the SPAD value of the top fully expanded leaf vs.the value of the third leaf,which takes into account the non-uniform N distribution within a canopy.The RSPAD can be used as an indicator for higher yield and NUE,and guide better management of N fertilizer application.Furthermore,we developed a new strategy of nitrogen-split application based on RSPAD,in which the N rate was reduced by 18.7%,yield was increased by 1.7%,and the agronomic N use efficiency was increased by 27.8%,when compared with standard farmers'practices.This strategy of N fertilization shows great potential for ensuring high yielding and improving NUE at lower N inputs.
基金supported by the National Key Research and Development Program of China (2022YFD2300304)the National Natural Science Foundation of China (32071944 and 32272197)+2 种基金the Hong Kong Research Grants Council, China (GRF 14177617, 12103219, 12103220, and AoE/M-403/16)the State Key Laboratory of Agrobiotechnology (Strategic Collaborative Projects) in The Chinese University of Hong Kong, China, the Six Talent Peaks Project in Jiangsu Province, China (SWYY151)the Project Funded by the Priority Academic Program Development of Jiangsu Higher Education Institutions, China (PAPD).
文摘Integrative cultivation practices(ICPs)are essential for enhancing cereal yield and resource use efficiency.However,the effects of ICP on the rhizosphere environment and roots of paddy rice are still poorly understood.In this study,four rice varieties were produced in the field.Each variety was treated with six different cultivation techniques,including zero nitrogen application(0 N),local farmers’practice(LFP),nitrogen reduction(NR),and three progressive ICP techniques comprised of enhanced fertilizer N practice and increased plant density(ICP1),a treatment similar to ICP1 but with alternate wetting and moderate drying instead of continuous flooding(ICP2),and the same practices as ICP2 with the application of organic fertilizer(ICP3).The ICPs had greater grain production and nitrogen use efficiency than the other three methods.Root length,dry weight,root diameter,activity of root oxidation,root bleeding rate,zeatin and zeatin riboside compositions,and total organic acids in root exudates were elevated with the introduction of the successive cultivation practices.ICPs enhanced nitrate nitrogen,the activities of urease and invertase,and the diversity of microbes(bacteria)in rhizosphere and non-rhizosphere soil,while reducing the ammonium nitrogen content.The nutrient contents(ammonium nitrogen,total nitrogen,total potassium,total phosphorus,nitrate,and available phosphorus)and urease activity in rhizosphere soil were reduced in all treatments in comparison with the non-rhizosphere soil,but the invertase activity and bacterial diversity were greater.The main root morphology and physiology,and the ammonium nitrogen contents in rhizosphere soil at the primary stages were closely correlated with grain yield and internal nitrogen use efficiency.These findings suggest that the coordinated enhancement of the root system and the environment of the rhizosphere under integrative cultivation approaches may lead to higher rice production.
文摘Leaf-color modification can affect canopy photosynthesis,with potential effects on rice yield and yield components.Modulating source-sink relationships through crop management is often used to improve crop productivity.This study investigated whether and how modifying leaf color alters source-sink relationships and whether current crop cultivation practices remain applicable for leaf-color modified genotypes.Periodically collected data of total biomass and nitrogen(N)accumulation in rice genotypes of four genetic backgrounds and their leaf-color modified variants(greener or yellower)were analyzed,using a recently established modelling method to quantify the source-sink(im)balance during grain filling.Among all leaf-color variants,only one yellower-leaf variant showed a higher source capacity than its normal genotype.This was associated with greater post-flowering N-uptake that prolonged the functional leaf-N duration,and this greater post-flowering N-uptake was possible because of reduced pre-flowering N-uptake.A density experiment showed that current management practices(insufficient planting density accompanied by abundant N application)are unsuitable for the yellower-leaf genotype,ultimately limiting its yield potential.Leaf-color modification affects source-sink relationships by regulating the N trade-off between pre-and post-flowering uptake,as well as N translocation between source and sink organs.To best exploit leaf-color modification for improving crop productivity,adjustments of crop management practices are required.
基金supported by the National Key Research and Development Program(2016YFD0300206-4,2018YFD0300800)the National Natural Science Foundation of China(31461143015,31771710,31871559)+4 种基金Young Elite Scientists Sponsorship Program by CAST(2016QNRC001)Six Talent Peaks Project in Jiangsu Province(SWYY-151)the Jiangsu Provincial Key Research and Development Program(Modern Agriculture)(BE2015320)the Project Funded by the Priority Academic Program Development of Jiangsu Higher Education Institutionsthe Top Talent Supporting Program of Yangzhou University(2015-01)。
文摘Phosphorus use efficiency(PUE)can be improved through cultivation techniques and breeding.However,little is known about rice(Oryza sativa L.)agronomic and physiological traits associated with high PUE.We characterized the agronomic and physiological traits of rice varieties with different tolerances to low phosphorus in nutrient solution.Two varieties with strong tolerance to low phosphorus(STVs)and two with weak tolerance(WTVs)were grown at normal(NP,control)and low phosphorus(LP,1/20 of NP)concentrations.Plants grown at LP produced significantly lower grain yield than those grown at NP.WTVs yields were lower than STVs yields.Compared to NP,LP significantly increased phosphorus translocation efficiency(PTE),internal phosphorus efficiency(IPE)and phosphorus harvest index(PHI).Under the LP condition,PTE and IPE were higher for STVs than for WTVs.LP also reduced tiller number,shoot biomass,leaf area index(LAI),leaf photosynthetic rate,and mean root diameter of both kinds of varieties at the main growth stages,but to a lower extent in STVs.LP significantly increased the number of productive tillers,root biomass,root-shoot ratio,root bleeding rate,and root acid phosphatase(RAP)activity.Total root length,root oxidation activity(ROA),and root total and active absorbing surface areas for STVs were significantly increased under LP,whereas the opposite responses were observed for WTVs.Total root length,ROA,root bleeding rate,root active absorbing surface area,and RAP activity were positively and significantly correlated with grain yield,PTE,and IPE.These results suggest that the tolerance of rice varieties to a low-phosphorus growth condition is closely associated with root growth with higher biomass and activity.
基金the National Natural Science Foundation of China(32071947,32071944,31871557)the Open Project of Jiangsu Key Laboratory of Crop Genetics and Physiology(YCSL202102)+1 种基金the Priority Academic Program Development of Jiangsu Higher Education Institutions(PAPD)the Postgraduate Research&Practice Innovation Program of Jiangsu province(KYCX21_3235).
文摘Root morphology and physiology influence aboveground growth and yield formation in rice.However,root morphological and physiological differences among rice varieties with differing nitrogen(N)sensitivities and their relationship with grain yield are still unclear.In this study,rice varieties differing in N sensitivity over many years of experiments were used.A field experiment with multiple N rates(0,90,180,270,and 360 kg ha^(-1))was conducted to elucidate the effects of N application on root morphology,root physiology,and grain yield.A pot experiment with root excision and exogenous application of 6-benzyladenine(6-BA)at heading stage was used to further verify the above effects.The findings revealed that(1)under the same N application rate,N-insensitive varieties(NIV)had relatively large root biomass(root dry weight,length,and number).Grain yield was associated with root biomass in NIV.The oxidation activity and zeatin(Z)+zeatin riboside(ZR)contents in roots obviously and positively correlated with grain yield in N-sensitive varieties(NSV),and accounted for its higher grain yield than that of NIV at lower N application rates(90 and 180 kg ha^(-1)).(2)The root dry weight required for equal grain yield of NIV was greater than that of NSV.Excision of 1/10 and 1/8 of roots at heading stage had no discernible effect on the yield of Liangyoupeijiu(NIV),and it significantly reduced yield by 11.5%and 21.3%in Tianyouhuazhan(NSV),respectively,compared to the treatment without root excision.The decrease of filled kernels and grain weight after root excision was the primary cause for the yield reduction.Root excision and exogenous 6-BA application after root excision had little influence on the root activity of NIV.The oxidation activity and Z+ZR contents in roots of NSV decreased under root excision,and the increase in the proportion of excised roots aggravated these effects.The application of exogenous 6-BA increased the root activity of NSV and increased filled kernels and grain weight,thereby reducing yield loss after root excision.Thus,the root biomass of NIV was large,and there may be a phenomenon of"root growth redundancy."Vigorous root activity was an essential feature of NSV.Selecting rice varieties with high root activity or increasing root activity by cultivation measures could lead to higher grain yield under lower N application rates.
基金supported by grants from the National Natural Science Foundation of China (31461143105, 31271641, 31471438)the National Key Technology R&D Program of China (2011BAD16B14, 2012BAD04B08, 2014AA10A605)the Priority Academic Program Development of Jiangsu Higher Education Institutions (PAPD-2014-2)
文摘While the yield potential of rice has increased but little is known about the impact of breeding on grain quality, especially under different levels of N availability. In order to investigate the integrated effects of breeding and N levels on rice quality 12 japonica rice cultivars bred in the past60 years in the Yangtze River Basin were used with three levels of N: 0 kg N ha-1, 240 kg N ha-1,and 360 kg N ha-1. During the period, milling quality(brown rice percentage, milled rice percentage, and head rice percentage), appearance quality(chalky kernels percentage, chalky size, and chalkiness), and eating and cooking quality(amylose content, gel consistency, peak viscosity, breakdown, and setback) were significantly improved, but the nutritive value of the grain has declined due to a reduction in protein content. Micronutrients, such as Cu, Mg, and S contents, were decreased, and Fe, Mn, Zn, Na, Ca, K, P, B contents were increased. These changes in grain quality imply that simultaneous improvements in grain yield and grain quality are possible through selection. Overall, application of N fertilizer decreased grain quality, especially in terms of eating and cooking quality. Under higher N levels, higher protein content was the main reason for deterioration of grain quality, although lower amylose content might contribute to improving starch pasting properties. These results suggest that further improvement in grain quality will depend on both breeding and cultivation practices, especially in regard to nitrogen and water management.
基金supported by the National Basic Research Program of China (2015CB150404)the National Key Research and Development Program of China (2016YFD0300206-4, 2018YFD0300801)+4 种基金the National Natural Science Foundation of China (31871559, 31671614)Young Elite Scientists Sponsorship Program by CAST (2016QNRC001)the Natural Science Foundation of the Jiangsu Higher Education Institutions (15KJA210005)the Project Funded by the Priority Academic Program Development of Jiangsu Higher Education Institutionsthe Top Talent Supporting Program of Yangzhou University (2015-01)
文摘In previous studies, integrative crop management (ICM) improved shoot growth and grain yield of rice (Oryza sativa L.). However, little is known about the effect of ICM on root growth and methane (CH4) emission of paddy rice. In this study, two rice varieties, Wuyunjing 24 and Yongyou 2640, were grown. A field experiment was conducted with three crop management treatments including zero nitrogen fertilization (0N), local farmer practice (LFP), and ICM. Root morphophysiological traits and CH4 emission from the paddy field were investigated. ICM significantly increased mean grain yield by 29.9%, with the effect attributed mainly to an increase in mean total number of spikelets by 26.4% compared to LFP. ICM increased root and shoot biomass, root length, number of roots, root oxidation activity (ROA), root bleeding rate, and root total and active absorbing surface area by respectively 24.4%, 25.7%, 17.1%, 9.3%, 18.7%, 29.5%, 12.1%, and 24.7%. The concentrations of malic, succinic, and acetic acids in root exudates were respectively 5.8%, 6.0%, and 10.5% higher in ICM than in LFP. Compared to LFP, ICM significantly decreased the rate of CH4 emission during emission peak stages and reduced total CH4 emission by 17.1%. The root morphophysiological traits were positively and significantly correlated with grain yield, whereas root length, specific root length, ROA, and root total and active absorbing surface area were negatively and significantly correlated with total CH4 emission. These results suggest that ICM could achieve the dual goals of increasing grain yield and reducing the greenhouse gas effect by improving the root morphology and physiological traits of paddy rice.
基金supported by grants from the National Basic Research Program of China(No.2012CB114306)the National Natural Science Foundation of China(Nos.31461143015,31271641,and 31471438)+3 种基金the National Key Technology R&D Program of China(Nos.2012BAD04B08 and 2014AA10A605)the Priority Academic Program Development of Jiangsu Higher Education Institutions(PAPD)the Top Talent Supporting Program of Yangzhou University(No.2015-01)Jiangsu Creation Program for Post-graduation Students(No.KYZZ15_0364)
文摘Polyamines(PAs) are important endogenous plant growth regulators responding to environmental stress and mediating many physiological processes including grain filling in cereals.This study investigated whether PAs mediate the effect of post-anthesis soil drying on starch granule size distribution,starch content,and weight of superior and inferior kernels of wheat(Triticum aestivum L.).Two wheat cultivars were grown in pots.Three treatments,well-watered(WW),moderate soil drying(MD) and severe soil drying(SD),were imposed from 9 days post-anthesis until maturity.PA levels in kernels and small,medium and large granules were measured.The results showed that superior kernels had much higher free spermidine(Spd) and free spermine(Spm) concentrations,larger volumes of medium starch granules,and smaller-sized large granules than did inferior kernels under all the treatments.Compared to WW,MD significantly increased the concentrations of free Spd and free Spm,activities of soluble starch synthase and granule-bound starch synthase,volume of medium granules,and starch content and kernel weight of inferior kernels,and decreased the size of large granules.SD produced the opposite effect.Application of Spd or Spm to spikes produced effects similar to those of MD,and application of an inhibitor of Spd and Spm synthesis produced effects similar to those of SD.These results suggest that PAs mediate the effect of post-anthesis soil drying on starch biosynthesis in wheat kernels by regulating key enzymes in starch synthesis and that elevated PA levels under MD increase the volume of medium granules and kernel weight of inferior kernels.
文摘Moutan Cortex (MC) has been demonstrated to have an inhibitive effect on inflammation and oxidative stress responses in mesangial cells in our previous study. However, little is known about the components of MC contributing to this benefit. In the present study, cell membrane immobilized chromatography (CMC), a fast and useful method, was presented for screening potential active components of MC. HBZY-1 cells were incubated with MC (200 μg/mL) at the optimal incubation time (90 min). HPLC-DAD analysis and LC/ESI/MS/MS were performed to distinguish the active components and identify its structural ion fragments. The results showed that eight components binding to HBZY-1 cells were mudanoside B, paeoniflorin sulfonate, paeoniflorin, tetragalloyl glucose (isomeride), hexagalloyl glucose, mudanopiside A, and paeonol. In conclusion, our established CMC might be a useful method for screening potential active components in complicated traditional Chinese medicines. These components might be associated with the efficacy of MC on prevention and treatment of diabetic nephropathy.
基金was supported by the Chinese National Natural Science Foundation of China(grant number 81371089)the Research Project of Wannan Medical College(grant number WK202122).
文摘Permanent damage to hair cells(HCs)is the leading cause of sensory deafness.Supporting cells(SCs)are essential in the restoration of hearing in mammals because they can proliferate and differentiate to HCs.MDS1 and EVI1 complex locus(MECOM)is vital in early development and cell differentiation and regulates the TGF-βsignaling pathway to adapt to pathophysiological events,such as hematopoietic proliferation,differentiation and cells death.In addition,MECOM plays an essential role in neurogenesis and craniofacial development.However,the role of MECOM in the development of cochlea and its way to regulate related signaling are not fully understood.To address this problem,this study examined the expression of MECOM during the development of cochlea and observed a significant increase of MECOM at the key point of auditory epithelial morphogenesis,indicating that MECOM may have a vital function in the formation of cochlea and regeneration of HCs.Meanwhile,we tried to explore the possible effect and potential mechanism of MECOM in SC proliferation and HC regeneration.Findings from this study indicate that overexpression of MECOM markedly increases the proliferation of SCs in the inner ear,and the expression of Smad3 and Cdkn2b related to TGF signaling is significantly down-regulated,corresponding to the overexpression of MECOM.Collectively,these data may provide an explanation of the vital function of MECOM in SC proliferation and trans-differentiation into HCs,as well as its regulation.The interaction between MECOM,Wnt,Notch and the TGF-βsignaling may provide a feasible approach to induce the regeneration of HCs.
基金supported by the National Natural Science Foundation of China (31471438, 31461143015, 31771710)the National Key Technology Support Program of China (2014AA10A605)+3 种基金the National Key Research and Development Program of China (2016YFD0300206-4)a Project Funded by the Priority Academic Program Development of Jiangsu Higher Education Institutions (PAPD)Jiangsu Creation Program for Post-graduation Students (KYLX16_1398)the Top Talent Supporting Program of Yangzhou University (2015-01)
文摘Brassinosteroids(BRs) play crucial roles in many aspects of plant development. However, their function in spikelet differentiation and degeneration in rice(Oryza sativa L.) remains unclear. Here, we investigated the roles of these phytohormones in spikelet development in fieldgrown rice subjected to five different nitrogen(N)fertilization treatments during panicle differentiation. BR levels and expression of genes involved in BR biosynthesis and signal transduction were measured in spikelets. Pollen fertility and the number of differentiated spikelets were closely associated with 24-epicastasterone(24-epiCS) and 28-homobrassinolide(28-homoBL) levels in spikelets.Enhanced BR biosynthesis and signal transduction, in response to N treatment, enhanced spikelet differentiation, reduced spikelet degeneration, and increased grain yield. Increases in proton-pumping ATPase activity, ATPconcentration, energy charge, and antioxidant system(AOS) levels were consistent with 24-epiCS and28-homoBL concentrations. Exogenous application of 24-epiCS or 28-homoBL on young panicles induced a marked increase in endogenous 24-epiCS or 28-homoBL levels, energy charge, AOS levels, spikelet differentiation, and panicle weight. The opposite effects were observed following treatment with a BR biosynthesis inhibitor. Our findings indicate that, in rice, BRs mediate the effects of N fertilization on spikelet development and play a role in promoting spikelet development through increasing AOS levels and energy charge during panicle development.
