Experiment was conducted at the Gongzhuling Experimental Station of Institute of Crop Sciences, Chinese Academy of Agricultural Sciences, Jilin Province, China, during 2009-2010. Six representative varieties of maize ...Experiment was conducted at the Gongzhuling Experimental Station of Institute of Crop Sciences, Chinese Academy of Agricultural Sciences, Jilin Province, China, during 2009-2010. Six representative varieties of maize （Baihe in the 1950s, Jidan 101 in the 1960s, Zhongdan 2 in the 1970s, Yedan 13 in the 1980s, Zhengdan 958 in the 1990s, and Xianyu 335 in the 2000s） were each planted under two different densities （52 500 and 82 500 plants ha-~） and two different nitrogen application levels （150 and 300 kg ha-l）. Root characteristics and distribution among soil layers were studied by the field root digging method. The results showed that root mass increased with the process of the growth and development of the plant, and it peaked at kernel filling stage, and decreased at maturity due to the root senesces. Root mass of different maize varieties from the 1950s to 1980s had a trend of increase, while it decreased for the modern varieties. Root length and root surface areas had the similar changing trend. The study suggested that early maize varieties may have root redundancy, and reducing root redundancy may be a direction for variety improvement for high yield. Root characteristics were affected by nitrogen application level and density; modern varieties were more suitable for higher fertilizer application level and density conditions. Root characteristics distribution among soil layers decreased by an exponent equation, but the regression coefficients of different varieties were different. Though the root length density （RLD） of every soil layer of different varieties also decreased by an exponent equation, there were large variations of RLD in every part of a layer.展开更多
The phosphorus uptake （PU） in above-ground parts of plant, root characteristics and root exudations as well as the quantitative trait loci （QTLs） associated with these characteristics were determined for a F2：3 p...The phosphorus uptake （PU） in above-ground parts of plant, root characteristics and root exudations as well as the quantitative trait loci （QTLs） associated with these characteristics were determined for a F2：3 population derived from the cross of two contrasting maize （Zea mays L.） genotypes, 082 and Yel07. A total of 241 F2：3 families were evaluated in replicated trials under deficient phosphorus conditions in 2007 at two sites （Kaixian County and Southwest University, Chongqing, P. R. China）. The results show pleiotropy and close linkage among QTLs. Four common regions in different environments were in bnlg100- bnlg1268b （bins 1.02） for QTL of H＋, bnlg1268a-umc1290a （bins 1.09） for QTL of AP （acid phospbatase activity）, dupssrl5- P 1MT/a （bins 6.06） for QTLs of PU （phosphorus uptake） and RW （root weight）, and P IM3/d-P1M3/g （bins9.04） for QTLs of PU and AP. These QTLs are non-environment or minor QTLs x environment. By epistatic analysis, three main QTLs and eighteen QTLs x QTLs interactions were detected for the seven measured characteristics. These QTLs may affect trait expression by epistatic interaction with the other loci, and make a substantial contribution to phosphorus utilization efficiency, which should be considered when breeding maize varieties with high P efficiency. Two regions were detected in dupssrl 5- P1MT/a （bins 6.06） for QTL of RW and P1M3/d- P 1M3/g （bins 9.04） for QTL of PU and AP. They were detected in two different environments and by two methods of QTL analysis, which were useful for marker-assisted selection.展开更多
Rice(Oryza sativa L.)root characteristics are closely associated with nitrogen(N)uptake,root growth and development are greatly influenced by ethylene.In this study,a hydroponic experiment was conducted using four ric...Rice(Oryza sativa L.)root characteristics are closely associated with nitrogen(N)uptake,root growth and development are greatly influenced by ethylene.In this study,a hydroponic experiment was conducted using four rice genotypes[Shanyou 63(SY63)and Zhonghua 11(ZH11)with well–developed aerenchyma;Yangdao 6(YD6)and mutant rcn1 from ZH11 with less–developed aerenchyma]to investigate the effects of exogenous ethephon(Eth)on root characteristics,N uptake,dry matter distribution,and clarify the underlying relationship.Compared with YD6 and rcn1,SY63 and ZH11 had higher N accumulation,higher root aerenchyma area to cortex area ratio(ACR),higher NH_(4)^(+)uptake via the apoplasmic pathway and root-to-shoot NH_(4)^(+)translocation under no ethephon application(NEth)and Eth treatment,and elevated expression of the three genes(OsAMT1;2,OsAMT2;2,and OsAMT4;1)for ammonium transporters under Eth treatment.Eth treatment increased shoot N and dry matter accumulation,decreased the total root length and root diameter,and increased ACR and the expression of OsAMT genes in four genotypes.In summary,Eth could increase N accumulation via modifying root characteristics in rice,particularly by enlarging root aerenchyma and thinning the roots.The findings provide implications for development of elite rice varieties and green rice production with higher N efficiency.展开更多
Forests play an important role in controlling the formation and movement processes of debris flows.They contribute to soil stabilization,regulation of soil water content,and act as robust structures impeding the downs...Forests play an important role in controlling the formation and movement processes of debris flows.They contribute to soil stabilization,regulation of soil water content,and act as robust structures impeding the downstream progression of debris flows.On the positive side,trees,to some extent,can intercept debris flows and effectively mitigate their velocity by increasing flow resistance.On the negative side,trees may suffer damage from debris-flow hazards,characterized by the generation of substantial quantities of wood fragments and consequential ramifications such as river channel blockage,resulting in backwater rise.In extreme cases,this blockage collapse can lead to instantaneous discharge amplification,thereby adversely impacting urban safety and impeding sustainable development.Therefore,in order to grasp the effects of tree characteristics on tree failure modes,the tree failure modes and corresponding parameters,diameters at breast height(DBH)and root-soil plate size,were identified and recorded through the post-event field investigation in Keze Gully,a region prone to debrisflow events in Sichuan,China,respectively.To investigate the impact of spatial variability in tree root distribution on tree failure modes,the root crosssectional area ratio(RAR),root density(RD),root length density(RLD)and soil detachment rate(SDR)were obtained.The findings indicated that:(1)Tree characteristics reflect the interactions of debris flows and trees,and influence the tree failure modes ultimately.The root distribution characteristics influence the size and shape of the root-soil plate to affect the resistance of trees.(2)Compared to burial and abrasion,stem breakage and overturning are the predominant modes of tree failure in debris-flow hazards.Trees with a smaller DBH primarily experience stem breakage and bending,and trees with a larger DBH mostly experience overturning.(3)The root-soil plate shapes of overturned trees,affected by the root architecture and root growth range,are generally semielliptical or semicircular,and the horizontal and vertical radii increase with DBH,but the correlation between the root-soil plate’s breadth-depth ratio and DBH is low.(4)The biomass and RAR decrease with distance.The RAR distribution exhibit the order of upslope direction>downslope direction>lateral direction.The coarse root biomass significantly increases with DBH,but no clear trend in fine root biomass.(5)The roots can significantly enhance the soil erosion resistance,but the erosion resistance of coarse roots is not as significant as that of fine roots.The erosion resistance increases with DBH,and follows the order of upslope direction>downslope direction>lateral direction.The results could provide new insights into the influences of tree and root distribution characteristics on tree failure modes during debris flows.展开更多
Effects of different media,pH values,temperatures,carbon and nitrogen sources on mycelial growth and sporulation of root rot pathogen on Sambucus chinensis was determined in the paper.The results showed that root rot ...Effects of different media,pH values,temperatures,carbon and nitrogen sources on mycelial growth and sporulation of root rot pathogen on Sambucus chinensis was determined in the paper.The results showed that root rot pathogen on S.chinensis was identified as Fusariumsp.The mycelial growth and sporulation of Fusariumsp.in PSA medium was the best;the optimal temperature for mycelial growth and sporulation was from 25℃ to 30℃ and the optimal temperature was 28℃;the suitable pH values for mycelial growth and sporulation was from 5 to 7,and the optimum pH value was 6;the absence or presence of carbon sources had significant effect on growth of Fusariumsp.;sucrose was the best carbon source utilized in mycelial growth,while lactose was the worst; KNO3 was the best nitrogen source utilized in mycelial growth,while（NH4） 2 SO4 was the worst one.展开更多
In order to study the infiltration characteristics of grassland soil in the super large scale landslides distribution area in the upper reaches of the Yellow River,this study selected the Xiazangtan super large scale ...In order to study the infiltration characteristics of grassland soil in the super large scale landslides distribution area in the upper reaches of the Yellow River,this study selected the Xiazangtan super large scale distribution area in Jianzha County as the study area.Through experiments and numerical simulations,plant roots characteristics,soil physical properties and infiltration characteristics of naturally grazed grassland and enclosed grassland with different slope directions were compared and analyzed,and the influence of rainfall on seepage field and stability of the two grassland slopes were discussed.The results show that the highest soil moisture infiltration capacity(FIR)is found on the shady slope of the enclosed grassland(2.25),followed by the sunny slope of the enclosed grassland(1.23)and the shady slope of the naturally grazed grassland(-0.87).Correlation analysis show that soil water content,root dry weight density,total soil porosity,number of forks and root length are positively correlated with infiltration rate(P<0.05),whereas soil dry density is negatively correlated with infiltration rate(P<0.05).The results of stepwise regression analyses show that soil water content,total soil porosity,root length and number of forks are the main factors affecting soil infiltration capacity.And the ability of roots to increase soil infiltration by improving soil properties is higher than the effect of roots itself.After 60 min of simulated rainfall,the safety factors of the shady slopes of naturally grazed grassland and enclosed grassland are reduced by 29.56%and 19.63%,respectively,comparing to those before rainfall.Therefore,in this study,the roots play a crucial role in regulating soil infiltration and enhance slope stability by increasing soil water content,soil total porosity and shear strength while decreasing soil dry density.The results of this study provide theoretical evidence and practical guidance for the effective prevention and control of secondary geological disasters such as soil erosion and shallow landslide on the slope of river banks in the study area by using plant ecological measures.展开更多
Yield losses of bread wheat due to crown rot can be more severe when drought conditions occur during the grain-filling period.Root architecture characteristics are important for soil exploration and belowground resour...Yield losses of bread wheat due to crown rot can be more severe when drought conditions occur during the grain-filling period.Root architecture characteristics are important for soil exploration and belowground resource acquisition and are essential for adaptation to water-limited environments.Traits such as root angle,length and density have been strongly associated with acquisition efficiency and contribute to yield stability of the crop.The impact of crown rot pathogens on wheat root architecture is poorly understood.We examined differences in root angle,length and number,as well as dry root weight of the crown rot-susceptible bread wheat cultivar,Livingston inoculated with one of two crown rot pathogens Fusarium culmorum or Fusarium pseudograminearum in a transparent-sided root observation chamber.Significant adverse impacts on plant health and growth were revealed by visual discolouration of the leaf sheaths;fresh and dry shoot weight;leaf area of the oldest and the youngest fully expanded leaf and leaf number.Values of most recorded root system measurements were reduced when inoculated with either F.culmorum or F.pseudograminearum.In contrast,root angle was increased in the presence of F.culmorum but was not significantly changed by F.pseudograminearum.The development of whiteheads and grain losses in bread wheat caused by crown rot have previously been associated with blockages of the vascular systems.The method employed here was able to identify differences in the pathogen impacts on roots,which were not detected using previous systems.This research indicates that in the presence of F.culmorum and F.pseudograminearum infection,not only reductions in the size and biomass of the shoot system but also changes in the length,biomass and architecture of the root system could play an important role in yield loss.展开更多
Plough pans （PPs）, common in the black-soil region of northeastern China, have significant effects on the root systems of crops. We conducted a field experiment to study the distribution of soybean roots under the i...Plough pans （PPs）, common in the black-soil region of northeastern China, have significant effects on the root systems of crops. We conducted a field experiment to study the distribution of soybean roots under the influence of PPs. The soybean roots showed compensatory growth above the PP, with higher root length and weight in soil with a PP compared to those without a PP. Roots were heavier and longer in the 15-75 cm soil layer without a PP than with a PP. Soil porosity was lower in the PP and the soil below the PP, which likely decreased the oxygen content of the soil and induced more growth of roots above the PP. The PP is also likely to decrease infiltration of rain-water and hinder the migration of nitrate downward, which in turn increased the density and length of soybean root hairs, which, hence, promoted growth.展开更多
It was studied that the evolution of root characteristics among 42 soybean varieties developed in Heilongjiang and Jilin Province in different years. The results showed that there were differences on the root characte...It was studied that the evolution of root characteristics among 42 soybean varieties developed in Heilongjiang and Jilin Province in different years. The results showed that there were differences on the root characteristics among soybean varieties. From 1950s to 1990s, root fresh weight, root volume, root surface, root dry weight, lateral root length of main root characters tendedly increased with the variable development展开更多
Long-term excessive nitrogen(N)application neither increases nor enhances grain yield and N use efficiency(NUE)of maize,yet the mechanisms involving root morphological and physiological characteristics remain unclear....Long-term excessive nitrogen(N)application neither increases nor enhances grain yield and N use efficiency(NUE)of maize,yet the mechanisms involving root morphological and physiological characteristics remain unclear.This study aimed to elucidate the mechanisms underlying stagnant grain yield under excessive N application by examining root morphological and physiological characteristics.A 10-year N fertilizer trial was conducted in Jilin Province,Northeast China,cultivating maize at three N fertilizer levels(zero N,N0;recommended N,N2;and high N level,N4)from 2019 to 2021.Two widely cultivated maize genotypes,‘Xianyu 335’(XY335)and‘Zhengdan 958’(ZD958),were evaluated.Grain yield,N content,root morphology,and physiological characteristics were analyzed to assess the relationships between N uptake,N utilization,plant growth,and root systems under different N treatments.Compared to N0,root biomass,post-silking N uptake,and grain yield improved significantly with increased N input,while no significant differences emerged between recommended N and high N.High N application enhanced root length and root surface area but decreased root activity(measured by TTC(2,3,5-triphenyltetrazolium chloride)method),nitrate reductase activity,and root activity absorbing area across genotypes.Root length and root to shoot ratio negatively affected N uptake(by-1.2 and-24.6%),while root surface area,root activity,nitrate reductase activity,and root activity absorbing area contributed positively.The interaction between cultivar and N application significantly influenced NUE.XY335 achieved the highest NUE(11.6%)and N recovery efficiency(18.4%)through superior root surface area(23.6%),root activity(12.5%),nitrate reductase activity(8.3%),and root activity absorbing area(6.9%)compared to other treatments.Recommended N application enhanced Post N uptake,NUE,and grain yield through improved root characteristics,while high N application failed to increase or decreased NUE by reducing these parameters.This study demonstrates that root surface area,root activity,nitrate reductase activity,and root activity absorbing area limit NUE increase under high N application.展开更多
A solution culture experiment was performed to investigate the effects of oxytetracycline （OTC） on wheat （Triticum aestivum L.） growth, chlorophyll contents, and photosynthesis at five levels of 0, 10, 20, 40, and...A solution culture experiment was performed to investigate the effects of oxytetracycline （OTC） on wheat （Triticum aestivum L.） growth, chlorophyll contents, and photosynthesis at five levels of 0, 10, 20, 40, and 80 mmol L-1 OTC. OTC is toxic to wheat. The wheat growth, especially wheat root was significantly decreased. Further OTC also significantly decreased root activity, chlorophyll contents, and photosynthetic parameters except for intercellular CO2 concentrations. The different responses of indicators such as root number, root activity and so on to OTC were also observed. The IC50 values for the tested indicators to OTC ranged from 7.1 to 113.4 mmol L-1 OTC. The order of indicator sensitivity to OTC was root number stomatal conductance chlorophyll a total chlorophyll photosynthetic rates total surface area transpiration rate chlorophyll b fresh weight of root dry weight of root total length dry weight of shoot = fresh weight of shoot total volume. The root number was more sensitive than other indicators with the IC50 value of 7.1 mmol L-1 OTC, and could be taken as the sensitive indicator to predict the hazards of OTC to wheat.展开更多
This study aimed to investigate the differences in shoot and root traits, and water use and water use efficiency（WUE） in drought tolerant（DT） maize（Zea mays L.） hybrids under full and deficit irrigated condition...This study aimed to investigate the differences in shoot and root traits, and water use and water use efficiency（WUE） in drought tolerant（DT） maize（Zea mays L.） hybrids under full and deficit irrigated conditions. A two-year greenhouse study was conducted with four hybrids（one conventional hybrid, 33D53AM, two commercial DT hybrids, P1151 AM, N75H, and an experimental hybrid, Exp HB） grown under two water regimes（I（100） and I（50）, referring to 100 and 50% of evapotranspiration requirements）. Under water stress, the hybids P1151 AM, N75, and Exp HB showed more drought tolerance and had either greater shoot dry weight or less dry weight reduction than the conventional hybrid（33 D53 AM）. However, these three hybrids responded to water stress using different mechanisms. Compared with the conventional hybrid, the two commercial DT hybrids（P1151 AM and N75H） had a smaller leaf area, shoot dry weight, and root system per plant. As a result, these hybrids used less water but had a higher WUE compared with the conventional hybrid. In contrast, the experimental hybrid（ExpHB） produced more shoot biomass by silking stage at both irrigation levels than all other hybrids, but it had relatively lower WUE. The hybrids demonstrated different drought response mechanisms that may require different irrigation management strategies. More investigation and validation are needed under field conditions and in different soil types.展开更多
This paper discusses the problem of the extraction of characteristic roots on Bessel-Neumann's mixed equations. It gives the expressions and the evaluation of the minimum root. The advantage of the method has no u...This paper discusses the problem of the extraction of characteristic roots on Bessel-Neumann's mixed equations. It gives the expressions and the evaluation of the minimum root. The advantage of the method has no use for the table of the multi-figure number Bessel function and it does not need computer but can calculate all the characteristic roots The precision of these roots is still high.展开更多
Soil erosion on the Loess Plateau of China is effectively controlled due to the implementation of several ecological restoration projects that improve soil properties and reduce soil erodibility. However, few studies ...Soil erosion on the Loess Plateau of China is effectively controlled due to the implementation of several ecological restoration projects that improve soil properties and reduce soil erodibility. However, few studies have examined the effects of vegetation restoration on soil properties and erodibility of gully head in the gully regions of the Loess Plateau. The objectives of this study were to quantify the effects of vegetation restoration on soil properties and erodibility in this region. Specifically, a control site in a slope cropland and 9 sites in 3 restored land-use types （5 sites in grassland, 3 in woodland and 1 in shrubland） in the Nanxiaohegou watershed of a typical gully region on the Loess Plateau were selected, and soil and root samples were collected to assess soil properties and root characteristics. Soil erodibility factor was calculated by the Erosion Productivity Impact Calculator method. Our results revealed that vegetation restoration increased soil sand content, soil saturated hydraulic conductivity, organic matter content and mean weight diameter of water-stable aggregate but decreased soil silt and clay contents and soil disintegration rate. A significant difference in soil erodibility was observed among different vegetation restoration patterns or land-use types. Compared with cropland, soil erodibility decreased in the restored lands by 3.99% to 21.43%. The restoration patterns of Cleistogenes caespitosa K. and Artemisia sacrorum L. in the grassland showed the lowest soil erodibility and can be considered as the optimal vegetation restoration pattern for improving soil anti-erodibility of the gully heads. Additionally, the negative linear change in soil erodibility for grassland with restoration time was faster than those of woodland and shrubland. Soil erodibility was significantly correlated with soil particle size distribution, soil disintegration rate, soil saturated hydraulic conductivity, water-stable aggregate stability, organic matter content and root characteristics （including root average diameter, root length density, root surface density and root biomass density）, but it showed no association with soil bulk density and soil total porosity. These findings indicate that although vegetation destruction is a short-term process, returning the soil erodibility of cropland to the level of grassland, woodland and shrubland is a long-term process （8-50 years）.展开更多
In the dynamics analysis and synthesis of a controlled system, it is important to know for what feedback gains can the controlled system decay to the demanded steady state as fast as possible. This article presents a ...In the dynamics analysis and synthesis of a controlled system, it is important to know for what feedback gains can the controlled system decay to the demanded steady state as fast as possible. This article presents a systematic method for finding the optimal feedback gains by taking the stability of an inverted pendulum system with a delayed proportional-derivative controller as an example. First, the condition for the existence and uniqueness of the stable region in the gain plane is obtained by using the D-subdivision method and the method of stability switch. Then the same procedure is used repeatedly to shrink the stable region by decreasing the real part of the rightmost characteristic root. Finally, the optimal feedback gains within the stable region that minimizes the real part of the rightmost root are expressed by an explicit formula. With the optimal feedback gains, the controlled inverted pendulum decays to its trivial equilibrium at the fastest speed when the initial values around the origin are fixed. The main results are checked by numerical simulation.展开更多
Techniques have been developed for the vegetative propagation of Tetraena mongolica,a rare and endangered species endemic to the western Ordos Plateau in the northcentral portion of China.The purpose of the study was ...Techniques have been developed for the vegetative propagation of Tetraena mongolica,a rare and endangered species endemic to the western Ordos Plateau in the northcentral portion of China.The purpose of the study was to investigate the rooting characteris-tics of the plant species from the aspects of length and ages of cuttings,external hormone concentration,leaf retention,cutting orientations,and cutting positions.The results obtained from the experiments indicated that the rooting ratio of 2-year or 3-year old cuttings was larger than more than of 4-year old cuttings.The influence of external hormone concentration on rooting was ob-vious;the rooting ratio of cuttings was increased by external hormone treatment,especially when treated by ABT1(ABT No.1 Rooting Powder) 50 mg/L for 3 hours,in which case,the rooting ratio reached 91 percent.Leaf retention influenced rooting sig-nificantly;the rooting rate of cuttings became greater as the leaf retention increased.There was no significant difference in rooting capability between south and north orientations of the ortets.The rooting ratio of the cuttings obtained from the distal portions of shoots was significantly larger than those obtained from the middle and the basal portions of the shoots.On day three after treat-ment,calluses started appearing at the incisions of some cuttings dipped in 500 mg/L IAA(indole acetic acid).Most cuttings were healed or swelled,and 6 percent of cuttings rooted on day 6 after treatment.Higher rooting period occurred 7-10 days after the experiment was set up.展开更多
This paper advances a new simplified formula for estimating variance components ,sums up the basic law to calculate the weights of observed values and a circulation method using the increaments of weights when estimat...This paper advances a new simplified formula for estimating variance components ,sums up the basic law to calculate the weights of observed values and a circulation method using the increaments of weights when estimating the variance components of traverse nets,advances the charicteristic roots method to estimate the variance components of traveres nets and presents a practical method to make two real and symmetric matrices two diagonal ones.展开更多
Improving rice yield and nitrogen use efficiency(NUE)are crucial challenges for coordinating food production and environmental health.However,little is known about the physiological mechanisms underlying the synergist...Improving rice yield and nitrogen use efficiency(NUE)are crucial challenges for coordinating food production and environmental health.However,little is known about the physiological mechanisms underlying the synergistic effects of high yield and NUE in rice.Using two near-isogenic rice lines(named DEP1 and dep1),a two-year field experiment was conducted to assess agronomic characteristics and the physiological characteristics of carbon and nitrogen translocation under three nitrogen levels.Compared with DEP1,dep1 had higher grain yield,grain filling percentage,nitrogen(N)uptake,and NUE.More non-structural carbohydrates(NSCs)and N in the stems were translocated to grains during grain filling in dep1 than in DEP1.Furthermore,stem NSCs translocation was significantly positively correlated with grain yield,while stem N translocation was significantly positively correlated with NUE.Key carbon metabolism enzyme activities(α-amylase,β-amylase and sucrose-phosphate synthase in stems,and sucrose synthase,ADP-glucose pyrophosphorylase and starch synthase in grains)and stem sucrose transporter gene(OsSUT1 and OsSWEET13)expression were higher in dep1 than in DEP1.This contributed to high stem NSCs translocation.Higher N translocation in the stems occurred due to the higher expression of OsNPF2.4.Moreover,the higher values of root morphological traits(root dry weight,root surface area,root length and root volume)and structural characteristics(stele diameter,cortical thickness and vessel section area)in dep1 explained its high nitrogen uptake.In addition,higher expression of OsNADH-GOGAT1 and OsGS1.3 promoted the assimilation of ammonium and contributed to higher nitrogen uptake in dep1.The application of N reduced carbon translocation but enhanced N translocation by regulating the corresponding metabolic enzyme activities and gene expression.Overall,these findings highlighted the roles of nitrogen uptake,and carbon and nitrogen translocation from stems as crucial characteristics for synergistically improving yield and NUE in the dep1 rice line.展开更多
This paper focuses on the stability testing of fractional-delay systems. It begins with a brief introduction of a recently reportedalgorithm, a detailed demonstration of a failure in applications of the algorithm and ...This paper focuses on the stability testing of fractional-delay systems. It begins with a brief introduction of a recently reportedalgorithm, a detailed demonstration of a failure in applications of the algorithm and the key points behind the failure. Then,it presents a criterion via integration, in terms of the characteristic function of the fractional-delay system directly, for testingwhether the characteristic function has roots with negative real parts only or not. As two applications of the proposed criterion,an algorithm for calculating the rightmost characteristic root and an algorithm for determining the stability switches, are proposed.The illustrative examples show that the algorithms work effectively in the stability testing of fractional-delay systems.展开更多
In this paper, we study a fractional order hybrid non-homogeneous ordinary diffe- rential equation. We gain r^ae^rt for the a order derivatives of both Riemann-Liouville type and Caputo type of function f（t） = e^rt ...In this paper, we study a fractional order hybrid non-homogeneous ordinary diffe- rential equation. We gain r^ae^rt for the a order derivatives of both Riemann-Liouville type and Caputo type of function f（t） = e^rt by letting integral lower limit of fractional derivative be -∞. It is first time for us to use the traditional eigenvalue method to solve fractional order ordinary differential equation. However, the law of the number of mutually independent arbitrary constants in general solutions to fractional order hy- brid non-homogeneous ordinary differential equation and general ordinary differential equation are very different.展开更多
基金supported by the National Basic Research Program of China (2009CB118605)the National Natural Sciences Foundation of China (31071362)the Key Technologies R&D Program of China during the 12th Five-Year Plan period (2011BAD16B08)
文摘Experiment was conducted at the Gongzhuling Experimental Station of Institute of Crop Sciences, Chinese Academy of Agricultural Sciences, Jilin Province, China, during 2009-2010. Six representative varieties of maize （Baihe in the 1950s, Jidan 101 in the 1960s, Zhongdan 2 in the 1970s, Yedan 13 in the 1980s, Zhengdan 958 in the 1990s, and Xianyu 335 in the 2000s） were each planted under two different densities （52 500 and 82 500 plants ha-~） and two different nitrogen application levels （150 and 300 kg ha-l）. Root characteristics and distribution among soil layers were studied by the field root digging method. The results showed that root mass increased with the process of the growth and development of the plant, and it peaked at kernel filling stage, and decreased at maturity due to the root senesces. Root mass of different maize varieties from the 1950s to 1980s had a trend of increase, while it decreased for the modern varieties. Root length and root surface areas had the similar changing trend. The study suggested that early maize varieties may have root redundancy, and reducing root redundancy may be a direction for variety improvement for high yield. Root characteristics were affected by nitrogen application level and density; modern varieties were more suitable for higher fertilizer application level and density conditions. Root characteristics distribution among soil layers decreased by an exponent equation, but the regression coefficients of different varieties were different. Though the root length density （RLD） of every soil layer of different varieties also decreased by an exponent equation, there were large variations of RLD in every part of a layer.
基金Funded by Chongqing Key Scientific and Technological Project (No. CSTC2007AB1045)Chinese Key Scientific and Technological Project (No. 2006BAD13B03)
文摘The phosphorus uptake （PU） in above-ground parts of plant, root characteristics and root exudations as well as the quantitative trait loci （QTLs） associated with these characteristics were determined for a F2：3 population derived from the cross of two contrasting maize （Zea mays L.） genotypes, 082 and Yel07. A total of 241 F2：3 families were evaluated in replicated trials under deficient phosphorus conditions in 2007 at two sites （Kaixian County and Southwest University, Chongqing, P. R. China）. The results show pleiotropy and close linkage among QTLs. Four common regions in different environments were in bnlg100- bnlg1268b （bins 1.02） for QTL of H＋, bnlg1268a-umc1290a （bins 1.09） for QTL of AP （acid phospbatase activity）, dupssrl5- P 1MT/a （bins 6.06） for QTLs of PU （phosphorus uptake） and RW （root weight）, and P IM3/d-P1M3/g （bins9.04） for QTLs of PU and AP. These QTLs are non-environment or minor QTLs x environment. By epistatic analysis, three main QTLs and eighteen QTLs x QTLs interactions were detected for the seven measured characteristics. These QTLs may affect trait expression by epistatic interaction with the other loci, and make a substantial contribution to phosphorus utilization efficiency, which should be considered when breeding maize varieties with high P efficiency. Two regions were detected in dupssrl 5- P1MT/a （bins 6.06） for QTL of RW and P1M3/d- P 1M3/g （bins 9.04） for QTL of PU and AP. They were detected in two different environments and by two methods of QTL analysis, which were useful for marker-assisted selection.
基金supported by the National Natural Science Foundation of China(31671598).
文摘Rice(Oryza sativa L.)root characteristics are closely associated with nitrogen(N)uptake,root growth and development are greatly influenced by ethylene.In this study,a hydroponic experiment was conducted using four rice genotypes[Shanyou 63(SY63)and Zhonghua 11(ZH11)with well–developed aerenchyma;Yangdao 6(YD6)and mutant rcn1 from ZH11 with less–developed aerenchyma]to investigate the effects of exogenous ethephon(Eth)on root characteristics,N uptake,dry matter distribution,and clarify the underlying relationship.Compared with YD6 and rcn1,SY63 and ZH11 had higher N accumulation,higher root aerenchyma area to cortex area ratio(ACR),higher NH_(4)^(+)uptake via the apoplasmic pathway and root-to-shoot NH_(4)^(+)translocation under no ethephon application(NEth)and Eth treatment,and elevated expression of the three genes(OsAMT1;2,OsAMT2;2,and OsAMT4;1)for ammonium transporters under Eth treatment.Eth treatment increased shoot N and dry matter accumulation,decreased the total root length and root diameter,and increased ACR and the expression of OsAMT genes in four genotypes.In summary,Eth could increase N accumulation via modifying root characteristics in rice,particularly by enlarging root aerenchyma and thinning the roots.The findings provide implications for development of elite rice varieties and green rice production with higher N efficiency.
基金supported by the National Natural Science Foundation of China (Grant No.41925030)the Nyingchi National Sustainable Development Experimental Zone Project (2023-SYQ-007)+1 种基金the Science and Technology Research Program of Institute of Mountain Hazards and Environment, Chinese Academy of Sciences (Grant No. IMHE-ZDRW-02)the Chinese Academy of Sciences Light of West China Program
文摘Forests play an important role in controlling the formation and movement processes of debris flows.They contribute to soil stabilization,regulation of soil water content,and act as robust structures impeding the downstream progression of debris flows.On the positive side,trees,to some extent,can intercept debris flows and effectively mitigate their velocity by increasing flow resistance.On the negative side,trees may suffer damage from debris-flow hazards,characterized by the generation of substantial quantities of wood fragments and consequential ramifications such as river channel blockage,resulting in backwater rise.In extreme cases,this blockage collapse can lead to instantaneous discharge amplification,thereby adversely impacting urban safety and impeding sustainable development.Therefore,in order to grasp the effects of tree characteristics on tree failure modes,the tree failure modes and corresponding parameters,diameters at breast height(DBH)and root-soil plate size,were identified and recorded through the post-event field investigation in Keze Gully,a region prone to debrisflow events in Sichuan,China,respectively.To investigate the impact of spatial variability in tree root distribution on tree failure modes,the root crosssectional area ratio(RAR),root density(RD),root length density(RLD)and soil detachment rate(SDR)were obtained.The findings indicated that:(1)Tree characteristics reflect the interactions of debris flows and trees,and influence the tree failure modes ultimately.The root distribution characteristics influence the size and shape of the root-soil plate to affect the resistance of trees.(2)Compared to burial and abrasion,stem breakage and overturning are the predominant modes of tree failure in debris-flow hazards.Trees with a smaller DBH primarily experience stem breakage and bending,and trees with a larger DBH mostly experience overturning.(3)The root-soil plate shapes of overturned trees,affected by the root architecture and root growth range,are generally semielliptical or semicircular,and the horizontal and vertical radii increase with DBH,but the correlation between the root-soil plate’s breadth-depth ratio and DBH is low.(4)The biomass and RAR decrease with distance.The RAR distribution exhibit the order of upslope direction>downslope direction>lateral direction.The coarse root biomass significantly increases with DBH,but no clear trend in fine root biomass.(5)The roots can significantly enhance the soil erosion resistance,but the erosion resistance of coarse roots is not as significant as that of fine roots.The erosion resistance increases with DBH,and follows the order of upslope direction>downslope direction>lateral direction.The results could provide new insights into the influences of tree and root distribution characteristics on tree failure modes during debris flows.
文摘Effects of different media,pH values,temperatures,carbon and nitrogen sources on mycelial growth and sporulation of root rot pathogen on Sambucus chinensis was determined in the paper.The results showed that root rot pathogen on S.chinensis was identified as Fusariumsp.The mycelial growth and sporulation of Fusariumsp.in PSA medium was the best;the optimal temperature for mycelial growth and sporulation was from 25℃ to 30℃ and the optimal temperature was 28℃;the suitable pH values for mycelial growth and sporulation was from 5 to 7,and the optimum pH value was 6;the absence or presence of carbon sources had significant effect on growth of Fusariumsp.;sucrose was the best carbon source utilized in mycelial growth,while lactose was the worst; KNO3 was the best nitrogen source utilized in mycelial growth,while（NH4） 2 SO4 was the worst one.
基金supported by the National Natural Science Foundation of China(42041006)the Natural Science Foundation of Qinghai Province(2020-ZJ-906).
文摘In order to study the infiltration characteristics of grassland soil in the super large scale landslides distribution area in the upper reaches of the Yellow River,this study selected the Xiazangtan super large scale distribution area in Jianzha County as the study area.Through experiments and numerical simulations,plant roots characteristics,soil physical properties and infiltration characteristics of naturally grazed grassland and enclosed grassland with different slope directions were compared and analyzed,and the influence of rainfall on seepage field and stability of the two grassland slopes were discussed.The results show that the highest soil moisture infiltration capacity(FIR)is found on the shady slope of the enclosed grassland(2.25),followed by the sunny slope of the enclosed grassland(1.23)and the shady slope of the naturally grazed grassland(-0.87).Correlation analysis show that soil water content,root dry weight density,total soil porosity,number of forks and root length are positively correlated with infiltration rate(P<0.05),whereas soil dry density is negatively correlated with infiltration rate(P<0.05).The results of stepwise regression analyses show that soil water content,total soil porosity,root length and number of forks are the main factors affecting soil infiltration capacity.And the ability of roots to increase soil infiltration by improving soil properties is higher than the effect of roots itself.After 60 min of simulated rainfall,the safety factors of the shady slopes of naturally grazed grassland and enclosed grassland are reduced by 29.56%and 19.63%,respectively,comparing to those before rainfall.Therefore,in this study,the roots play a crucial role in regulating soil infiltration and enhance slope stability by increasing soil water content,soil total porosity and shear strength while decreasing soil dry density.The results of this study provide theoretical evidence and practical guidance for the effective prevention and control of secondary geological disasters such as soil erosion and shallow landslide on the slope of river banks in the study area by using plant ecological measures.
基金supported by a USQ Postgraduate Research Scholarship and the Queensland Government。
文摘Yield losses of bread wheat due to crown rot can be more severe when drought conditions occur during the grain-filling period.Root architecture characteristics are important for soil exploration and belowground resource acquisition and are essential for adaptation to water-limited environments.Traits such as root angle,length and density have been strongly associated with acquisition efficiency and contribute to yield stability of the crop.The impact of crown rot pathogens on wheat root architecture is poorly understood.We examined differences in root angle,length and number,as well as dry root weight of the crown rot-susceptible bread wheat cultivar,Livingston inoculated with one of two crown rot pathogens Fusarium culmorum or Fusarium pseudograminearum in a transparent-sided root observation chamber.Significant adverse impacts on plant health and growth were revealed by visual discolouration of the leaf sheaths;fresh and dry shoot weight;leaf area of the oldest and the youngest fully expanded leaf and leaf number.Values of most recorded root system measurements were reduced when inoculated with either F.culmorum or F.pseudograminearum.In contrast,root angle was increased in the presence of F.culmorum but was not significantly changed by F.pseudograminearum.The development of whiteheads and grain losses in bread wheat caused by crown rot have previously been associated with blockages of the vascular systems.The method employed here was able to identify differences in the pathogen impacts on roots,which were not detected using previous systems.This research indicates that in the presence of F.culmorum and F.pseudograminearum infection,not only reductions in the size and biomass of the shoot system but also changes in the length,biomass and architecture of the root system could play an important role in yield loss.
基金supported by the National Natural Science Foundation of China (51239009,41301288,51479032 and 51409213)the Postdoctoral Science Foundation of China (2014M561317)+2 种基金the Heilongjiang Postdoctoral Financial Assistance,China (LBH-Z13023)the Heilongjiang Provincial Department of Education Science and Technology Research Project,China (12541039)the Young Talents Project of Northeast Agricultural University,China (14QC48)
文摘Plough pans （PPs）, common in the black-soil region of northeastern China, have significant effects on the root systems of crops. We conducted a field experiment to study the distribution of soybean roots under the influence of PPs. The soybean roots showed compensatory growth above the PP, with higher root length and weight in soil with a PP compared to those without a PP. Roots were heavier and longer in the 15-75 cm soil layer without a PP than with a PP. Soil porosity was lower in the PP and the soil below the PP, which likely decreased the oxygen content of the soil and induced more growth of roots above the PP. The PP is also likely to decrease infiltration of rain-water and hinder the migration of nitrate downward, which in turn increased the density and length of soybean root hairs, which, hence, promoted growth.
文摘It was studied that the evolution of root characteristics among 42 soybean varieties developed in Heilongjiang and Jilin Province in different years. The results showed that there were differences on the root characteristics among soybean varieties. From 1950s to 1990s, root fresh weight, root volume, root surface, root dry weight, lateral root length of main root characters tendedly increased with the variable development
基金supported by the National Key Research and Development Program of China(2023YFD2301702)the earmarked Fund for China Agriculture Research System(CARS-02)the National Natural Science Foundation of China(31971852).
文摘Long-term excessive nitrogen(N)application neither increases nor enhances grain yield and N use efficiency(NUE)of maize,yet the mechanisms involving root morphological and physiological characteristics remain unclear.This study aimed to elucidate the mechanisms underlying stagnant grain yield under excessive N application by examining root morphological and physiological characteristics.A 10-year N fertilizer trial was conducted in Jilin Province,Northeast China,cultivating maize at three N fertilizer levels(zero N,N0;recommended N,N2;and high N level,N4)from 2019 to 2021.Two widely cultivated maize genotypes,‘Xianyu 335’(XY335)and‘Zhengdan 958’(ZD958),were evaluated.Grain yield,N content,root morphology,and physiological characteristics were analyzed to assess the relationships between N uptake,N utilization,plant growth,and root systems under different N treatments.Compared to N0,root biomass,post-silking N uptake,and grain yield improved significantly with increased N input,while no significant differences emerged between recommended N and high N.High N application enhanced root length and root surface area but decreased root activity(measured by TTC(2,3,5-triphenyltetrazolium chloride)method),nitrate reductase activity,and root activity absorbing area across genotypes.Root length and root to shoot ratio negatively affected N uptake(by-1.2 and-24.6%),while root surface area,root activity,nitrate reductase activity,and root activity absorbing area contributed positively.The interaction between cultivar and N application significantly influenced NUE.XY335 achieved the highest NUE(11.6%)and N recovery efficiency(18.4%)through superior root surface area(23.6%),root activity(12.5%),nitrate reductase activity(8.3%),and root activity absorbing area(6.9%)compared to other treatments.Recommended N application enhanced Post N uptake,NUE,and grain yield through improved root characteristics,while high N application failed to increase or decreased NUE by reducing these parameters.This study demonstrates that root surface area,root activity,nitrate reductase activity,and root activity absorbing area limit NUE increase under high N application.
基金supported by the National Natural Science Foundation of China (40701163)the Natural Science Foundation of Beijing City, China (6092019)+1 种基金the International Foundation for Science, Stockholm, Sweden, the Organization for the Prohibition of Chemical Weapons, the Hague, and the Netherlands, through a grant to Li Zhaojun (C/4076)the National Basic Research Program of China (973 Program, 2007CB109305)
文摘A solution culture experiment was performed to investigate the effects of oxytetracycline （OTC） on wheat （Triticum aestivum L.） growth, chlorophyll contents, and photosynthesis at five levels of 0, 10, 20, 40, and 80 mmol L-1 OTC. OTC is toxic to wheat. The wheat growth, especially wheat root was significantly decreased. Further OTC also significantly decreased root activity, chlorophyll contents, and photosynthetic parameters except for intercellular CO2 concentrations. The different responses of indicators such as root number, root activity and so on to OTC were also observed. The IC50 values for the tested indicators to OTC ranged from 7.1 to 113.4 mmol L-1 OTC. The order of indicator sensitivity to OTC was root number stomatal conductance chlorophyll a total chlorophyll photosynthetic rates total surface area transpiration rate chlorophyll b fresh weight of root dry weight of root total length dry weight of shoot = fresh weight of shoot total volume. The root number was more sensitive than other indicators with the IC50 value of 7.1 mmol L-1 OTC, and could be taken as the sensitive indicator to predict the hazards of OTC to wheat.
基金supported in part by the UDSA-Ogallala Aquifer ProgramTexas A&M Agri Life Research Cropping System Program, USAthe USDA National Institute of Food and Agriculture Hatch Project, USA (TEX09438)
文摘This study aimed to investigate the differences in shoot and root traits, and water use and water use efficiency（WUE） in drought tolerant（DT） maize（Zea mays L.） hybrids under full and deficit irrigated conditions. A two-year greenhouse study was conducted with four hybrids（one conventional hybrid, 33D53AM, two commercial DT hybrids, P1151 AM, N75H, and an experimental hybrid, Exp HB） grown under two water regimes（I（100） and I（50）, referring to 100 and 50% of evapotranspiration requirements）. Under water stress, the hybids P1151 AM, N75, and Exp HB showed more drought tolerance and had either greater shoot dry weight or less dry weight reduction than the conventional hybrid（33 D53 AM）. However, these three hybrids responded to water stress using different mechanisms. Compared with the conventional hybrid, the two commercial DT hybrids（P1151 AM and N75H） had a smaller leaf area, shoot dry weight, and root system per plant. As a result, these hybrids used less water but had a higher WUE compared with the conventional hybrid. In contrast, the experimental hybrid（ExpHB） produced more shoot biomass by silking stage at both irrigation levels than all other hybrids, but it had relatively lower WUE. The hybrids demonstrated different drought response mechanisms that may require different irrigation management strategies. More investigation and validation are needed under field conditions and in different soil types.
文摘This paper discusses the problem of the extraction of characteristic roots on Bessel-Neumann's mixed equations. It gives the expressions and the evaluation of the minimum root. The advantage of the method has no use for the table of the multi-figure number Bessel function and it does not need computer but can calculate all the characteristic roots The precision of these roots is still high.
基金supported by the National Natural Science Foundation of China(41571275)the Western Action Plan Project of the Chinese Academy of Sciences(KZCX-XB3-13)the Major Program of the National Natural Science Foundation of China(41790444/D0214)
文摘Soil erosion on the Loess Plateau of China is effectively controlled due to the implementation of several ecological restoration projects that improve soil properties and reduce soil erodibility. However, few studies have examined the effects of vegetation restoration on soil properties and erodibility of gully head in the gully regions of the Loess Plateau. The objectives of this study were to quantify the effects of vegetation restoration on soil properties and erodibility in this region. Specifically, a control site in a slope cropland and 9 sites in 3 restored land-use types （5 sites in grassland, 3 in woodland and 1 in shrubland） in the Nanxiaohegou watershed of a typical gully region on the Loess Plateau were selected, and soil and root samples were collected to assess soil properties and root characteristics. Soil erodibility factor was calculated by the Erosion Productivity Impact Calculator method. Our results revealed that vegetation restoration increased soil sand content, soil saturated hydraulic conductivity, organic matter content and mean weight diameter of water-stable aggregate but decreased soil silt and clay contents and soil disintegration rate. A significant difference in soil erodibility was observed among different vegetation restoration patterns or land-use types. Compared with cropland, soil erodibility decreased in the restored lands by 3.99% to 21.43%. The restoration patterns of Cleistogenes caespitosa K. and Artemisia sacrorum L. in the grassland showed the lowest soil erodibility and can be considered as the optimal vegetation restoration pattern for improving soil anti-erodibility of the gully heads. Additionally, the negative linear change in soil erodibility for grassland with restoration time was faster than those of woodland and shrubland. Soil erodibility was significantly correlated with soil particle size distribution, soil disintegration rate, soil saturated hydraulic conductivity, water-stable aggregate stability, organic matter content and root characteristics （including root average diameter, root length density, root surface density and root biomass density）, but it showed no association with soil bulk density and soil total porosity. These findings indicate that although vegetation destruction is a short-term process, returning the soil erodibility of cropland to the level of grassland, woodland and shrubland is a long-term process （8-50 years）.
基金supported by the National Natural Science Foundation of China (Grant 11372354)the Fund of the State Key Lab of Mechanics and Control of Mechanical Structures (Grant MCMS-0116K01)
文摘In the dynamics analysis and synthesis of a controlled system, it is important to know for what feedback gains can the controlled system decay to the demanded steady state as fast as possible. This article presents a systematic method for finding the optimal feedback gains by taking the stability of an inverted pendulum system with a delayed proportional-derivative controller as an example. First, the condition for the existence and uniqueness of the stable region in the gain plane is obtained by using the D-subdivision method and the method of stability switch. Then the same procedure is used repeatedly to shrink the stable region by decreasing the real part of the rightmost characteristic root. Finally, the optimal feedback gains within the stable region that minimizes the real part of the rightmost root are expressed by an explicit formula. With the optimal feedback gains, the controlled inverted pendulum decays to its trivial equilibrium at the fastest speed when the initial values around the origin are fixed. The main results are checked by numerical simulation.
基金funded by the Natural Science Foundation of Inner Mongolia
文摘Techniques have been developed for the vegetative propagation of Tetraena mongolica,a rare and endangered species endemic to the western Ordos Plateau in the northcentral portion of China.The purpose of the study was to investigate the rooting characteris-tics of the plant species from the aspects of length and ages of cuttings,external hormone concentration,leaf retention,cutting orientations,and cutting positions.The results obtained from the experiments indicated that the rooting ratio of 2-year or 3-year old cuttings was larger than more than of 4-year old cuttings.The influence of external hormone concentration on rooting was ob-vious;the rooting ratio of cuttings was increased by external hormone treatment,especially when treated by ABT1(ABT No.1 Rooting Powder) 50 mg/L for 3 hours,in which case,the rooting ratio reached 91 percent.Leaf retention influenced rooting sig-nificantly;the rooting rate of cuttings became greater as the leaf retention increased.There was no significant difference in rooting capability between south and north orientations of the ortets.The rooting ratio of the cuttings obtained from the distal portions of shoots was significantly larger than those obtained from the middle and the basal portions of the shoots.On day three after treat-ment,calluses started appearing at the incisions of some cuttings dipped in 500 mg/L IAA(indole acetic acid).Most cuttings were healed or swelled,and 6 percent of cuttings rooted on day 6 after treatment.Higher rooting period occurred 7-10 days after the experiment was set up.
文摘This paper advances a new simplified formula for estimating variance components ,sums up the basic law to calculate the weights of observed values and a circulation method using the increaments of weights when estimating the variance components of traverse nets,advances the charicteristic roots method to estimate the variance components of traveres nets and presents a practical method to make two real and symmetric matrices two diagonal ones.
基金funded by the National Natural Science Foundation of China(32272200 and 31901425)the Jiangsu Provincial Key Research and Development Program,China(BE2021361)+2 种基金the Jiangsu Provincial Carbon Peak and Carbon Neutrality Technology Innovation Special Fund Project,China(BE2022425)the Priority Academic Program Development of Jiangsu Higher Education Institutions,China(PAPD)the Lv Yang Jin Feng Talent Plan of Yangzhou City,China(YZLYJFJH2022YXBS020)。
文摘Improving rice yield and nitrogen use efficiency(NUE)are crucial challenges for coordinating food production and environmental health.However,little is known about the physiological mechanisms underlying the synergistic effects of high yield and NUE in rice.Using two near-isogenic rice lines(named DEP1 and dep1),a two-year field experiment was conducted to assess agronomic characteristics and the physiological characteristics of carbon and nitrogen translocation under three nitrogen levels.Compared with DEP1,dep1 had higher grain yield,grain filling percentage,nitrogen(N)uptake,and NUE.More non-structural carbohydrates(NSCs)and N in the stems were translocated to grains during grain filling in dep1 than in DEP1.Furthermore,stem NSCs translocation was significantly positively correlated with grain yield,while stem N translocation was significantly positively correlated with NUE.Key carbon metabolism enzyme activities(α-amylase,β-amylase and sucrose-phosphate synthase in stems,and sucrose synthase,ADP-glucose pyrophosphorylase and starch synthase in grains)and stem sucrose transporter gene(OsSUT1 and OsSWEET13)expression were higher in dep1 than in DEP1.This contributed to high stem NSCs translocation.Higher N translocation in the stems occurred due to the higher expression of OsNPF2.4.Moreover,the higher values of root morphological traits(root dry weight,root surface area,root length and root volume)and structural characteristics(stele diameter,cortical thickness and vessel section area)in dep1 explained its high nitrogen uptake.In addition,higher expression of OsNADH-GOGAT1 and OsGS1.3 promoted the assimilation of ammonium and contributed to higher nitrogen uptake in dep1.The application of N reduced carbon translocation but enhanced N translocation by regulating the corresponding metabolic enzyme activities and gene expression.Overall,these findings highlighted the roles of nitrogen uptake,and carbon and nitrogen translocation from stems as crucial characteristics for synergistically improving yield and NUE in the dep1 rice line.
基金supported by the National Natural Science Foundation of China (Grant Nos. 10825207 and 11032009)the Program for Changjiang Scholars and Innovative Research Team in University (Grant No. IRT0968)
文摘This paper focuses on the stability testing of fractional-delay systems. It begins with a brief introduction of a recently reportedalgorithm, a detailed demonstration of a failure in applications of the algorithm and the key points behind the failure. Then,it presents a criterion via integration, in terms of the characteristic function of the fractional-delay system directly, for testingwhether the characteristic function has roots with negative real parts only or not. As two applications of the proposed criterion,an algorithm for calculating the rightmost characteristic root and an algorithm for determining the stability switches, are proposed.The illustrative examples show that the algorithms work effectively in the stability testing of fractional-delay systems.
基金jointly supported by the education department of Fujian provincial science and technology project Class A(JA13352)
文摘In this paper, we study a fractional order hybrid non-homogeneous ordinary diffe- rential equation. We gain r^ae^rt for the a order derivatives of both Riemann-Liouville type and Caputo type of function f（t） = e^rt by letting integral lower limit of fractional derivative be -∞. It is first time for us to use the traditional eigenvalue method to solve fractional order ordinary differential equation. However, the law of the number of mutually independent arbitrary constants in general solutions to fractional order hy- brid non-homogeneous ordinary differential equation and general ordinary differential equation are very different.
