Unbalanced fertilizer application with high intensity nitrogen(N)and insufficient potassium(K)results in declining soil fertility.Balanced fertilization represents an effective approach to reduce fertilizer usage whil...Unbalanced fertilizer application with high intensity nitrogen(N)and insufficient potassium(K)results in declining soil fertility.Balanced fertilization represents an effective approach to reduce fertilizer usage while enhancing maize yield and efficiency.This study examined two N levels(180 and 225 kg N ha^(-1),abbreviated N12 and N15)and four K treatments(0,75,150,and 75+75 kg K_(2)O ha^(-1),abbreviated K0,K5,K10,and K5+5)to investigate the effects of combined N and K application on biomass,nutrient accumulation,and remobilization characteristics in waxy maize.Results indicated that grain yield increased with higher K application at constant N levels,demonstrating an average increase of 1,254.8 kg ha^(-1)(2020)and 727.3 kg ha^(-1)(2021)compared with K0.Under identical N and K applications,K5+5 enhanced grain yield through increased kernel weight.The K5+5 treatment showed no significant difference in biomass and nutrient accumulation between N12 and N15.Compared to K10,K5+5 enhanced both the average remobilization amount(RBA)of biomass and increased RBA of N,phosphorus(P)and K.Additionally,the average remobilization efficiency(RBE)of biomass,N,P,and K in K5+5 increased by 3.3,4.6,10.6,and 4.2%,respectively.Moreover,topdressing K improved the apparent contribution to grain(AC)of biomass,N,P and K,facilitating greater nutrient transfer to grains and significantly increasing nutrient harvest index.Based on yield and fertilizer use efficiency,this study recommends optimized K application(basal and topdressing 75 kg ha^(-1))and moderate reduction in N application(from 225 to 180 kg ha^(-1))for spring-sown waxy maize production in southern China.展开更多
In order to improve the management of nitrogen(N) fertilization in pear orchards, we investigated the effects of application timing on the distribution, storage, and remobilization of N in mature pear trees in a field...In order to improve the management of nitrogen(N) fertilization in pear orchards, we investigated the effects of application timing on the distribution, storage, and remobilization of N in mature pear trees in a field experiment at Jingtai County, Gansu Province, China. Nine trees were selected for the experiment and each received equal aliquots of 83.33 g N in the autumn, spring, and summer, with ^(15)N-labeled(NH_4)_2SO_4 used in one of the aliquots each season. Results showed that the(^(15)NH_4)_2SO_4 applied in the autumn remained in the soil during the winter. In the following spring this N was absorbed and rapidly remobilized into each organ, especially new organs(leaves, fruit and new shoots). The ^(15)N supplied in spring was rapidly transported to developing fruit between the young fruit and fruit enlargement stages. ^(15)N from the summer application of fertilizer was mainly stored in the coarse roots over the winter, then was mobilized to support growth of new organs in spring. In conclusion, for pear trees we recommend that the autumn application of N-fertilizer be soon after fruit harvest in order to increase N stores in fine roots. Spring application should be between full bloom and the young fruit stages to meet the high N demands of developing fruit. Summer application of fertilizer at the fruit enlargement stage does not contemporaneously affect the growth of pears, but increases the N stored in coarse roots, and in turn the amount available for remobilization in spring.展开更多
The Zhaxikang Pb-Zn-Ag-Sb deposit, the largest polymetallic deposit known in the Himalayan Orogen of southern Tibet, is characterized by vein-type mineralization that hosts multiple mineral assemblages and complicated...The Zhaxikang Pb-Zn-Ag-Sb deposit, the largest polymetallic deposit known in the Himalayan Orogen of southern Tibet, is characterized by vein-type mineralization that hosts multiple mineral assemblages and complicated metal associations. The deposit consists of at least six steeply dipping vein- type orebodies that are hosted by Early Jurassic black carbonaceous slates and are controlled by a Cenozoic N-S-striking normal fault system. This deposit records multiple stages of mineralization that include an early period （A） of massive coarse-grained galena-sphalerite deposition and a later period （B） of Sb-bearing vein-type mineralization. Period A is only associated with galena-sphalerite mineralization, whereas period B can be subdivided into ferrous rhodochrosite-sphalerite-pyrite, quartz -sulfosalt-sphalerite, calcite-pyrite, quartz-stibnite, and quartz-only stages of mineralization. The formation of brecciated galena and sphalerite ores during period A implies reworking of pre-existing Pb -Zn sulfides by Cenozoic tectonic deformation, whereas period B mineralization records extensive open- space filling during ore formation. Fluid inclusion microthermometric data indicate that both periods A and B were associated with low-medium temperature （187-267℃） and low salinity （4.00-10.18% wt. NaCl equivalent） ore-forming fluids, although variations in the physical-chemical nature of the period B fluids suggest that this phase of mineralization was characterized by variable water/rock ratios. Microprobe analyses indicate that Fe concentrations in sphalerite decrease from period A to period B, and can be divided into three groups with FeS concentrations of 8.999-9.577, 7.125-9.109, 5.438-1.460 mol.%. The concentrations of Zn, Sb, Pb, and Ag within orebodies in the study area are normally distributed in both lateral and vertical directions, and Pb, Sb, and/or Ag concentrations are positive correlation within the central part of these orebodies, but negatively correlate in the margins. Sulfide S isotope compositions are highly variable （4‰-13‰）, varying from 4‰ to 11‰ in period A and 10‰ to 1‰ in period B. The Pb isotope within these samples is highly radiogenic and defines linear trends in 206pb/204pb vs. 207pb/204pb and 206pb/204pb vs. 208pb/204pb diagrams, respectively. The S and Pb isotopic characteristics indicate that the period B orebodies formed by mixing of Pb-Zn sulfides and regional Sb- bearing fluids. These features are indicative of overprinting and remobilization of pre-existing Pb-Zn sulfides by Sb-bearing ore-forming fluids during a post-collisional period of the Himalayan Orogeny. The presence of similar ore types in the north Rhenish Massif that formed after the Variscan Orogeny suggests that Zhaxikang-style mineralization may be present in other orogenic belts, suggesting that this deposit may guide Pb-Zn exploration in these areas.展开更多
The photosynthetic characteristics of flag leaf and the accumulation and remobilization of pre-anthesis dry mass（DM） and nitrogen（N） in vegetable organs in nine wheat cultivars under different source-sink manipula...The photosynthetic characteristics of flag leaf and the accumulation and remobilization of pre-anthesis dry mass（DM） and nitrogen（N） in vegetable organs in nine wheat cultivars under different source-sink manipulation treatments including defoliation（DF）, spike shading（SS） and half spikelets removal（SR） were investigated. Results showed that the SS treatment increased the photosynthetic rate（Pn） of flag leaf in source limited cultivar, but had no significant effect on sink limited cultivar. The SR treatment decreased the Pn of flag leaf. Grain DM accumulation was limited by source in some cultivars, in other cultivars, it was limited by sink. Grain N accumulation was mainly limited by source supply. The contribution of pre-anthesis dry mass to grain yield from high to low was stem, leaf and chaff, while the contribution of pre-anthesis N to grain N from high to low was leaf, stem and chaff. Cultivars S7221 and TA9818 can increase the contribution of remobilization of DM and N to grain at the maximum ratio under reducing source treatments, which may be the major reason for these cultivars having lower decrease in grain yield and N content under reducing source treatments.展开更多
Stay green(SG) maize was found to have higher grain yield and post-silking nitrogen(N) uptake(PostN) compared with a non-stay green(NSG) hybrid. To understand the effects of plant density on grain yield(GY) and N effi...Stay green(SG) maize was found to have higher grain yield and post-silking nitrogen(N) uptake(PostN) compared with a non-stay green(NSG) hybrid. To understand the effects of plant density on grain yield(GY) and N efficiency in modern maize hybrids, we compared two modern hybrids(SG hybrid DY508 and NSG hybrid NH101) with similar maturity ratings at three plant densities(45 000, 60 000, and 75 000 pl ha^–1) in 2014 and 2015. GY, leaf senescence, dry matter(DM) accumulation,N accumulation, PostN, and post-silking N remobilization(RemN) were analyzed. DY508 and NH101 had similar GY, but DY508 had higher thousand kernel weight(TKW) and lower kernel number(KN) than NH101. Plant density significantly increased GY in the two hybrids. On average, over the two years, plant density improved GY in DY508 and NH101 by 18.5 and 11.1%, respectively, but there were no differences in total dry matter(TDM) and post-silking DM(PostDM) between the two hybrids. Plant density improved leaf N, stem N, and grain N at the silking and maturity stages in 2014 and 2015. DY508 was lower in harvest index(HI), nitrogen harvest index(NHI), and grain N concentration(GNC) than NH101. Grain N in DY508 was 2.61 kg ha^–1 less than in NH101, and this was caused by lower GNC and leaf RemN. On the average, DY508 was 1.62 kg ha^–1 less in leaf remobilized N(leaf RemN) than NH101, but was similar in stem remobilized N(stem RemN;2.47 kg ha^–1 vs. 3.41 kg ha^–1). Maize hybrid DY508 shows delayed leaf senescence in the upper and bottom canopy layers in the later stages of growth. The present study provides evidence that the NH101, which has rapid leaf senescence at the late grain-filling stage, has gained equivalent GY and higher leaf RemN, and was more efficient in N utilization.展开更多
Foliar nitrogen(N)application is an effective strategy to improve protein content and quality in wheat kernels,but the specific effects of N forms remain unclear.In a two-year field study,foliar application of various...Foliar nitrogen(N)application is an effective strategy to improve protein content and quality in wheat kernels,but the specific effects of N forms remain unclear.In a two-year field study,foliar application of various N forms(NO_(3)^(-),urea,NH_(4)^(+))at anthesis was performed to measure their effects on wheat grain protein accumulation,quality formation,and the underlying mechanisms.Foliar application of three N forms showed varying effects in improving grain gluten proteins and quality traits.Under NH_(4)^(+) application,there was more post-anthesis N uptake for grain filling,with relatively strong increase in enzyme activities and gene expression associated with N metabolism in flag leaves at 8–20 days after anthesis(DAA),whereas its promotion of grain N metabolism became weaker after 20 DAA than those under NO_(3)^(-) and urea treatments.More N was remobilized from source organs to grain under treatment with foliar NO_(3)^(-) and urea.Genes controlling the synthesis of gluten protein and disulfide bonds were upregulated by NO_(3)^(-) and urea at 20–28 DAA,contributing to increased grain protein content and quality.Overall,foliar applications of NO_(3)^(-) and urea were more effective than those of NH_(4)^(+) in increasing grain N filling.These findings show that manipulating the source–sink relationship by reinforcing grain N metabolism and N remobilization is critical for optimizing grain protein accumulation and quality formation.展开更多
Maize growth,organ development,and yield formation are highly controlled by the manner in which the plant captures,partition,and remobilizes biomass and phosphorus(P).Better understanding of biomass and P accumulation...Maize growth,organ development,and yield formation are highly controlled by the manner in which the plant captures,partition,and remobilizes biomass and phosphorus(P).Better understanding of biomass and P accumulation,partition,and remobilization processes will improve modeling of crop resource use.However,there is still a lack of detailed data to parameterize the modeling of these processes,particula rly for modern maize cultivars.A two-year(2016 and 2017)field experiment with three P fertilization treatments(0(P0),75(P75),and 300(P300)kg P_(2)O_(5)ha^(-1))was conducted on a Fluvo-aquic soil(Quzhou,Hebei province,China)to collect data and quantify key processes for a representative modern maize cultivar(Zhengdan 958)widely grown in China.The proportions of biomass and P partitioned into various maize organs were unaffected by P application rate.Zhengdan 958 showed a much lower leaf-senescence rate than older cultivars,resulting in post-silking leaf photosynthesis being sufficient to meet grain biomass demand.In contrast,50%-85%of leaf P and 15%-50%of stem P accumulated pre-silking were remobilized into grain,in spite of the large proportion of post-silking P uptake.Our results are consistent with the theory that plants use resources according to the priority order of re-allocation from senescence followed by assimilation and uptake,with the re-translocation of reserves last.The results also enabled us to estimate the threshold P concentrations of Zhengdan 958 for modeling crop P demand.The critical leaf P concentration for individual leaves was 0.25%-0.30%,with a corresponding specific leaf P(SLP)of 75-100 mg P m^(-2).The structural P concentration for leaf was 0.01%,corresponding to an SLP of 3.8 mg P m^(-2).The maximum P concentrations of leaves and stems were 0.33%and 0.29%.The residual P concentration for stems was 0.006%.展开更多
The genesis of the giant Dongshengmiao in the northern margin of the North China Block has been debated since its discovery in the 1950 s,because it shows geological and geochemical characteristics with both syngeneti...The genesis of the giant Dongshengmiao in the northern margin of the North China Block has been debated since its discovery in the 1950 s,because it shows geological and geochemical characteristics with both syngenetic and epigenetic signatures.It has geological settings and sulfur and lead isotopic compositions that are similar with typical SEDEX（sedimentary exhalative） deposit,while the Zn-Pb-Cu mineralization was controlled by shear deformation and metamorphism,showing similarities with orogenic-type deposits.In this contribution,both the syngenetic and epigenetic features of the Dongshengmiao are envisaged,and accounted for in the context of a genetic model with two metallogenic periods.Massive pyrite at the Dongshengmiao was mostly recrystallized during metamorphism,but finegrained texture was locally preserved,indicating its syngenetic origin.On the contrary,all the Zn-Pb-Cu ores observed in this study show characteristics of epigenetic hydrothermal mineralization that controlled by metamorphism and accompanying shear deformation.The sulfur and lead isotopic compositions of sphalerite and galena indicate that they were in situ remobilized from a syngenetic stratabound source,and the oxygen and hydrogen isotopic ratios of ore-fluid indicate that the large-scale remobilization was assisted by metamorphic fluid.The thermodynamic modeling indicates that the orefluid during remobilization has a great potential of transporting Cu.This may account for the abnormally enriched Cu in the remobilized SEDEX deposit.The metamorphic fluid might strip Cu from the fluid source during devolatilization,and overprint it on the Zn-Pb orebodies during remobilization.A secondary flowthrough modeling reveals that Zn- and Cu-sulfides would be preferentially redistributed in Fe-rich carbonates during remobilization,as a result of fluid-rock interaction.Conclusively,a multistage genetic model is proposed.During the development of the Proterozoic rift,stratabound Zn-Pb mineralization took place in a SEDEX ore-forming system.The syngenetic sulfides subsequently underwent a large-scale fluidassisted remobilization during the early Cretaceous metamorphism and thrusting,forming the shear zone-controlled epigenetic orebodies.During the remobilization process,Cu was scavenged from the source of metamorphic fluid,and deposited accompanying remobilized Zn-Pb sulfides.Shear structures and Fe-rich carbonates are ideal sites for redistribution and re-deposition of remobilized sulfide.展开更多
Phosphate deficiency is one of the leading causes of crop productivity loss.Phospholipid degradation liberates phosphate to cope with phosphate deficiency.Glycerophosphodiester phosphodiesterases(GPX-PDEs)hydrolyse th...Phosphate deficiency is one of the leading causes of crop productivity loss.Phospholipid degradation liberates phosphate to cope with phosphate deficiency.Glycerophosphodiester phosphodiesterases(GPX-PDEs)hydrolyse the intermediate products of phospholipid catabolism glycerophosphodiesters into glycerol-3-phosphate,a precursor of phosphate.However,the function of GPX-PDEs in phosphate remobilization in maize remains unclear.In the present study,we characterized two phosphate deficiency-inducible GPX-PDE genes,ZmGPX-PDE1 and ZmGPX-PDE5,in maize leaves.ZmGPX-PDE1 and ZmGPX-PDE5 were transcriptionally regulated by ZmPHR1,a well-described phosphate starvation-responsive transcription factor of the MYB family.Complementation of the yeast GPX-PDE mutant gde1Δindicated that ZmGPX-PDE1 and ZmGPX-PDE5 functioned as GPX-PDEs,suggesting their roles in phosphate recycling from glycerophosphodiesters.In vitro enzyme assays showed that ZmGPX-PDE1 and ZmGPX-PDE5 catalysed glycerophosphodiester degradation with different substrate preferences for glycerophosphoinositol and glycerophosphocholine,respectively.ZmGPX-PDE1 was upregulated during leaf senescence,and more remarkably,loss of ZmGPXPDE1 inmaize compromised the remobilization of phosphorus fromsenescing leaves to young leaves,resulting in a stay-green phenotype under phosphate starvation.These results suggest that ZmGPX-PDE1 catalyses the degradation of glycerophosphodiesters in maize,promoting phosphate recycling from senescing leaves to new leaves.This mechanism is crucial for improving phosphorus utilization efficiency in crops.展开更多
Winter jujube orchard nitrogen （N） management aims at increasing N reserves to meet the tree＇s growth requirements. Fertilization strategies should maximize the efficiency of fertilizers, including the choice of th...Winter jujube orchard nitrogen （N） management aims at increasing N reserves to meet the tree＇s growth requirements. Fertilization strategies should maximize the efficiency of fertilizers, including the choice of the optimal timing of N supply. ^15N-urea was applied to winter jujubes on Jinsixiaozao jujubes rootstock to evaluate the effect of application timing on Nstorage and remobilization in mature trees in pot culture. The treatments consisted of ground application before budding （BB）, during fruit core-hardening stage （FCH）, and fruit rapid-swelling stage （FRS）. Nitrogen-use efficiency of treatments were significantly different, which were 2.42% （BB）, 9.77% （FCH）, and 9.01% （FRS） in the dormant and 5.20% （BB）, 16.16% （FCH）, and 10.30% （FRS） in the following full-bloom. N supply in the pre-harvest helped to increase N-reserves of trees and then translocate to the new growth organs the following year. The largest amount of ^15N was detected in the roots and trunks. In all the treatments, the partition rates were highest in coarse roots, which were 30.43% （BB）, 38.61% （FCH）, and 40.62% （FRS）, respectively. ^15N stored in roots and trunks was used by jujube trees to sustain new growth in the following full-bloom. ^15N applied before budding resulted in lower Ndff% in perennial organs （trunks and coarse roots） sampled in the following full-bloom, but fine roots had highest Ndff% （1.28%）. Other organs recovered similar amount of Ndff%. In contrast, FCH and FRS treatments led to higher Ndff% （4.01-5.15%） in the new growth organs （new growth branches, deciduous spurs, leaves and flowers）, but lower Ndff% in perennial branches （1.49-2.89%）. With the delay of ^15N-urea application time, ^15N increased the partitioning to roots. FCH treatment increased N-storage in perennial organ during winter, which should be remobilized to sustain new growth the following spring.展开更多
Pectin contributes greatly to cell wall phosphorus(P)remobilization.However,it is currently unclear whether the methylesterification degree of the pectin,which is related to the activity of pectin methylesterases(PMEs...Pectin contributes greatly to cell wall phosphorus(P)remobilization.However,it is currently unclear whether the methylesterification degree of the pectin,which is related to the activity of pectin methylesterases(PMEs),is also involved in this process.Here,we demonstrated that elevated PME activity can facilitate the remobilization of P deposited in the cell wall.P-deficient conditions resulted in the reduction of root cell wall P content.This reduction was more pronounced in Nipponbare than in Kasalath,in company with a significant increment of the PME activity,indicating a possible relationship between elevated PME activity and cell wall P remobilization.This hypothesis was supported by in vitro experiments,as pectin with lower methylesterification degree had higher ability to release inorganic P(Pi)from insoluble FePO_(4).Furthermore,among the 35 OsPME members in rice,only the expression of OsPME14 showed a relationship with PME activity.In addition,transgenic rice lines overexpressing OsPME14 had increased PME activity,released more P from the root cell wall,and more resistant to P deficiency.In conclusion,PMEs enhance P remobilization in P-starved rice by increasing PME activity in Nipponbare,which in turn helps to remobilize P from the cell wall,and thus makes more available P.展开更多
Slope farmland is a main type of agricultural land throughout northeast China.Long-term high intensity utilization and unreasonable farming have caused the deterioration of soil resources and a decrease in crop produc...Slope farmland is a main type of agricultural land throughout northeast China.Long-term high intensity utilization and unreasonable farming have caused the deterioration of soil resources and a decrease in crop production.Here,it was hypothesized that crop straw incorporation might help to reduce nutrient losses and increase maize yields across time and space.A field experiment for testing straw management practices on maize across three slope positions(top,back and bottom slopes)was conducted in Northeast China in 2018 and 2019.In this study,the dry matter accumulation(DMA),N accumulation(NA),N remobilization,postsilking N uptake and grain yield were measured under SI(straw incorporation)and NSI(no straw incorporation)across three slope positions of 100-m-long consecutive black soil slope farmland during the maize(Zea mays L.)growth stages.Compared with NSI,SI significantly increased DMA and NA at the silking and maturity stages.SI typically increased the N remobilization in all slope positions,and significantly increased N remobilization efficiency and contribution of N remobilization to grain on the back and bottom slopes.However,post-silking N uptake was only increased by SI on the top slope.SI generally increased the crop yield in three slope positions.In the SI treatments,the bottom slope was the highest yield position,followed by the top,and then the back slopes,suggesting that the bottom slope position of regularly incorporated straw might have increased the potential for boosting maize yield.Overall,the study demonstrated the outsized potential of straw incorporation to enhance maize NA and then increase the grain yield in black soil slope farmland.展开更多
Phosphorus(P)is an essential macronutrient for plant growth and development.Vacuoles play a crucial role in inorganic phosphate(Pi)storage and remobilization in plants.However,the physiological function of vacuolar ph...Phosphorus(P)is an essential macronutrient for plant growth and development.Vacuoles play a crucial role in inorganic phosphate(Pi)storage and remobilization in plants.However,the physiological function of vacuolar phosphate efflux transporters in plant Pi remobilization remains obscure.Here,we identified three Zm VPE genes(ZmVPE1,ZmVPE2a,ZmVPE2b)by combining them with transcriptome and quantitative real-time polymerase chain reaction(PCR)analyses,showing a relatively higher expression in older leaves than in younger leaves in maize.Moreover,the expression of the ZmVPEs was triggered by Pi deficiency and abscisic acid.ZmVPEs were localized to the vacuolar membrane and responsible for vacuolar Pi efflux.Compared with the wild-type,Pi remobilization from older to younger leaves was enhanced in Zm VPE-overexpression lines.zmvpe2a mutants displayed an increase in the total P and Pi concentrations in older leaves,but a decrease in younger leaves.In rice,Pi remobilization was impaired in the osvpe1osvpe2 double mutant and enhanced in OsVPE-overexpression plants,suggesting conserved functions of VPEs in modulating Pi homeostasis and remobilization in crop plants.Taken together,our findings revealed a novel mechanism underlying Pi remobilization from older to younger leaves mediated by plant vacuolar Pi efflux transporters,facilitating the development of Pi-efficient crop plants.展开更多
Translocation of absorbed phosphorus （P） from metabolically inactive sites to active sites in plants growing under P deprivation may increase its P utilization efficiency （PUE）. Acclimation to phosphate （Pi） sta...Translocation of absorbed phosphorus （P） from metabolically inactive sites to active sites in plants growing under P deprivation may increase its P utilization efficiency （PUE）. Acclimation to phosphate （Pi） starvation may be caused by a differential storage pool of vacuolar P, its release, and the intensity of re-translocation of absorbed P as P starvation inducible environmental cues （PSlEC） from ambient environment. Biomass assay and three P forms, namely inorganic （Pi）, organic （Po）, and acid-soluble total （Ptas） were estimated in Brassica cultivars exposed to 10 d P deprivation in the culture media. Considering that -aPi/at denotes the rate of Pi release, Pi release velocity （RSPi） was determined as the tangent to the equations obtained for Pi f（t） at the mean point in the period of greatest Pi decrease, whereas the inverse of the RSPi was an estimate of the internal Pi buffering capacity （IBCPi）. Inter cultivar variations in size of the non-metabolic Pi pool, RSPi, re-translocation of Pi from less to more active metabolic sites, and preferential Pi source and sink compartments were evaluated under P starvation. The cultivar ＇Brown Raya＇ showed the highest Pi storage ability under adequate external P supply, and a more intensive release than ＇Rain Bow＇ and ＇Dunkled＇ under P stress. Cultivar ＇B.S.A＇ was inferior to ＇Con-l＇ in its ability to store and use Pi. Roots and upper leaves were the main sink of Pi stored in the lower and middle leaves of all cultivars and showed lower IBCPi and larger RSPi values than lower and middle leaves. In another trial, six cultivars were exposed to P-free nutrition for 29 d after initial feeding on optimum nutrition for 15 d. With variable magnitude, all of the cultivars re-translocatad P from the above ground parts to their roots under P starvation, and [P] at 44 d after transplanting was higher in developing leaves compared with developed leaves. Under P deprivation, translocation of absorbed P from metabolically inactive to active sites may have helped the tolerant cultivars to establish a better rooting system, which provided a basis for tolerance against P starvation and increased PUE. A better understanding of the extent to which changes in the flux of P absorption and re-translocation under PSIEC will help to scavenge Pi from bound P reserves and will bring more sparingly soluble P into cropping systems and obtain capitalization of P reserves.展开更多
Monocarpic senescence,characterized by whole-plant senescence following a single flowering phase,is widespread in seed plants,particularly in crops,determining seed harvest time and quality.However,how external and in...Monocarpic senescence,characterized by whole-plant senescence following a single flowering phase,is widespread in seed plants,particularly in crops,determining seed harvest time and quality.However,how external and internal signals are systemically integrated into monocarpic senescence remains largely unknown.Here,we report that the Arabidopsis thaliana transcription factor WRKY1 plays essential roles in multiple key steps of monocarpic senescence.WRKY1 expression is induced by age,salicylic acid(SA),and nitrogen(N)deficiency.Flowering and leaf senescence are accelerated in the WRKY1 overexpression lines but are delayed in the wrky1 mutants.The combined DNA affinity purification sequencing and RNA sequencing analyses uncover the direct target genes of WRKY1.Further studies show that WRKY1 coordinately regulates three processes in monocarpic senescence:(1)suppressing FLOWERING LOCUS C gene expression to initiate flowering,(2)inducing SA biosynthesis genes to promote leaf senescence,and(3)activating the N assimilation and transport genes to trigger N remobilization.In summary,our study reveals how one stress-responsive transcription factor,WRKY1,integrates flowering,leaf senescence,and N remobilization processes into monocarpic senescence,providing important insights into plant lifetime regulation.展开更多
Japan has a limited amount of readily developable land.Sites are used and reused with alternating phases of excavation and deposition of man-made strata(MMS).The Great East Japan earthquake of 11th March 2011 caused w...Japan has a limited amount of readily developable land.Sites are used and reused with alternating phases of excavation and deposition of man-made strata(MMS).The Great East Japan earthquake of 11th March 2011 caused widespread damage due to ground waves and associated liquefaction-fluidization of MMS.A site at Kamisu City,Ibaraki Prefecture,was significantly affected.There,a gravel pit had been filled,partly excavated and then refilled.In 2003 it was found that a nearby drinking water well was seriously contaminated with arsenic.The site was sampled using a grid of boreholes and then excavated within a sheet pile enclosure at the source of the arsenic.The pollution came from large blocks that had been made by mixing cement with DiPhenylArsinic Acid powder and wastes that had been illegally dumped during refilling.The blocks were excavated and removed.Contaminated groundwater was pumped out and purified and the excavation was filled.展开更多
A critical challenge for global food security and sustainable agriculture is enhancing crop yields while reducing chemical N inputs.Improving N use efficiency in crops is essential for increasing agricultural producti...A critical challenge for global food security and sustainable agriculture is enhancing crop yields while reducing chemical N inputs.Improving N use efficiency in crops is essential for increasing agricultural productivity.The aim of this study was to evaluate the impacts of intercropping maize with leguminous green manure on grain yield and N utilization under reduced N-fertilization conditions.A field experiment with a split-plot design was conducted in northwestern China from 2018 to 2021.The main plots consisted of two cropping systems:maize-common vetch intercropping(IM)and sole maize(SM).The subplots had three N levels:zero N application(N0,0 kg ha^(-1)),a 25%reduction from the traditional chemical N supply(N1,270 kg ha^(-1)),and the traditional chemical N supply(N2,360 kg ha^(-1)).The results showed that the negative effects of N reduction on maize grain yield and N uptake were compensated by intercropping leguminous green manure,and the improvements increased with cultivation years.The integrated system involving maize-leguminous green manure intercropping and a reduced N supply enhanced N translocation from maize vegetative organs to grains and increased the nitrate reductase and glutamine synthetase activities in maize leaves.The supercompensatory effect in maize leaves increased year by year,reaching values of 16.1,21.3,and 25.5%in 2019,2020,and 2021,respectively.These findings suggest that intercropping maize with leguminous green manure under reduced chemical N input can enhance N assimilation and uptake in maize.By using this strategy,chemical fertilizer is effectively replaced by leguminous green manure,thereby improving N use efficiency and maintaining stable yields in the maize-based intercropping system.展开更多
This study aimed to analyze the absorption, utilization and transfer char- acteristics of nitrogen in high-yield winter wheat （Triticum aestivum） cultivars at dif- ferent sowing dates, so as to determine the optimum...This study aimed to analyze the absorption, utilization and transfer char- acteristics of nitrogen in high-yield winter wheat （Triticum aestivum） cultivars at dif- ferent sowing dates, so as to determine the optimum sowing dates for different high-yield wheat cultivars. A field experiment was conducted in the Shajiang black soil of Anhui Province with Jimai 22, Wanrnai 52 and Zhoumai 22, and the effects of early sowing （October 3）, optimum sowing （October 12） and late sowing （October 30） on wheat plant N content and accumulation, pre-and post-anthesis N accumula- tion （NA） of total plant, nitrogen remobUization to grain （NR）, N remobilization effi- ciency （NRE）, contribution of N remobilized to grain （NRC）, grain yield, N use effi- ciency （NUE） and N harvest index （NHI） of different wheat cultivar were investigat- ed. The results showed that sowing date had an impact on N content, absorption and utilization in wheat plants at various growth stages. The NA, NR and NRC of aboveground vegetative organs of wheat before anthesis were higher than those af- ter anthesis. Under the condition of late sowing, the grain N accumulation mainly depended on the N absorption by vegetative organs before anthesis. Under the conditions of optimum and early sowing, the absorbed N after anthesis accounted for a large proportion in grain N accumulation. The N uptake intensity and relative cumulative rate differed greatly among different growth stages and different-genotype wheat cultivars, and the pre-anthesis NA, pre-anthesis NR, pre-anthesis NRE, post- anthesis N assimilation amount and post-anthesis NRC showed significant differ- ences among different wheat cultivars. The grain yields of different wheat cultivars under the early and optimum sowing were all higher than those under the late sowing. The NHI and grain N accumulation were highest under the optimum sow- ing, and the latter significantly decreased with the delay of sowing dates. In con- trast, the NUE was highest under the late sowing, reaching 35.95%-41.32%. It indi- cated that under the condition of late sowing, most of the nitrogen was not ab- sorbed by wheat, but the use efficiency of the absorbed nitrogen significantly in- creased. In overall, the three high-yield wheat cultivars were all suitable for early and optimum sowing. Under the condition of late sowing, the yield of Zhoumai 22 showed the smallest differences with those under early and optimum sowing, and its NUE was significantly improved. Therefore, among the three high-yield wheat culti- vars, Zhoumai 22 was most suitable for late sowing.展开更多
Increased grain yield(GY) and grain protein concentration(GPC) are the two main targets of efforts to improve wheat(Triticum aestivum L.) production in the North China Plain(NCP). We conducted a three-year field exper...Increased grain yield(GY) and grain protein concentration(GPC) are the two main targets of efforts to improve wheat(Triticum aestivum L.) production in the North China Plain(NCP). We conducted a three-year field experiment in the 2014–2017 winter wheat growing seasons to compare the effects of conventional irrigation practice(CI) and micro-sprinkling irrigation combined with nitrogen(N) fertilizer(MSI) on GY, GPC, and protein yield(PY). Across the three years, GY, GPC, and PY increased by 10.5%–16.7%, 5.4%–8.0%, and 18.8%–24.6%, respectively, under MSI relative to CI. The higher GY under MSI was due primarily to increased thousand-kernel weight(TKW). The chlorophyll content of leaves was higher under MSI during the mid–late grain filling period, increasing the contribution of post-anthesis dry matter accumulation to GY, with consequent increases in total dry matter accumulation and harvest index compared to CI. During the mid–late grain filling period, the canopy temperature was markedly lower and the relative humidity was higher under MSI than under CI. The duration and rate of filling during the mid–late grain filling period were also higher under MSI than CI, resulting in higher TKW. MSI increased the contribution of post-anthesis N accumulation to grain N but reduced the pre-anthesis remobilization of N in leaves, the primary site of photosynthetic activity, possibly helping maintain photosynthate production in leaves during grain filling. Total N at maturity was higher under MSI than CI,although there was little difference in N harvest index. The higher GPC under MSI than under CI was due to a larger increase in grain N accumulation than in GY. Overall, MSI simultaneously increased both GY and GPC in winter wheat grown in the NCP.展开更多
Ammonium(NH+4) is the main nitrogen(N) form for rice crops, while NH+4near the root surface can be oxidized to nitrate(NO-3)by NH+4-oxidizing bacteria. Nitrate can be accumulated within rice tissues and reused when N ...Ammonium(NH+4) is the main nitrogen(N) form for rice crops, while NH+4near the root surface can be oxidized to nitrate(NO-3)by NH+4-oxidizing bacteria. Nitrate can be accumulated within rice tissues and reused when N supply is insufficient. We compared the remobilization of NO-3stored in the tissue and vacuolar between two rice(Oryza sativa L.) cultivars, Yangdao 6(YD6, indica)with a high N use efficiency(NUE) and Wuyujing 3(WYJ3, japonica) with a low NUE and measured the uptake of NO-3, expression of nitrate reductase(NR), NO-3transporter genes(NRTs), and NR activity after 4 d of N starvation following 7-d cultivation in a solution containing 2.86 mmol L-1NO-3. The results showed that both tissue NO-3concentration and vacuolar NO-3activity were higher in YD6 than WYJ3 under N starvation. YD6 showed a 2- to 3-fold higher expression of OsNRT2.1 in roots on the 1st and 4th day of N starvation and had significantly higher values of NO-3uptake(maximum uptake velocity, Vmax) than the cultivar WYJ3.Furthermore, YD6 had significantly higher leaf and root maximum NR activity(NRAmax) and actual NR activity(NRAact) as well as stronger root expression of the two NR genes after the 1st day of N starvation. There were no significant differences in NRAmax and NRAact between the two rice cultivars on the 4th day of N starvation. The results suggested that YD6 had stronger NRA under N starvation, which might result in better NO-3re-utilization from the vacuole, and higher capacity for NO-3uptake and use, potentially explaining the higher NUE of YD6 compared with WYJ3.展开更多
基金the financial support of the Jiangsu Agricultural Industry Technology System of China(JATS[2022]497)the Jiangsu Agriculture Science and Technology Innovation Fund,China(CX[23]3117)+2 种基金the Key Research&Development Program of Jiangsu Province,China(BE2021317)the National Natural Science Foundation of China(32101828)the Priority Academic Program Development of Jiangsu Higher Education Institutions,China(PAPD)。
文摘Unbalanced fertilizer application with high intensity nitrogen(N)and insufficient potassium(K)results in declining soil fertility.Balanced fertilization represents an effective approach to reduce fertilizer usage while enhancing maize yield and efficiency.This study examined two N levels(180 and 225 kg N ha^(-1),abbreviated N12 and N15)and four K treatments(0,75,150,and 75+75 kg K_(2)O ha^(-1),abbreviated K0,K5,K10,and K5+5)to investigate the effects of combined N and K application on biomass,nutrient accumulation,and remobilization characteristics in waxy maize.Results indicated that grain yield increased with higher K application at constant N levels,demonstrating an average increase of 1,254.8 kg ha^(-1)(2020)and 727.3 kg ha^(-1)(2021)compared with K0.Under identical N and K applications,K5+5 enhanced grain yield through increased kernel weight.The K5+5 treatment showed no significant difference in biomass and nutrient accumulation between N12 and N15.Compared to K10,K5+5 enhanced both the average remobilization amount(RBA)of biomass and increased RBA of N,phosphorus(P)and K.Additionally,the average remobilization efficiency(RBE)of biomass,N,P,and K in K5+5 increased by 3.3,4.6,10.6,and 4.2%,respectively.Moreover,topdressing K improved the apparent contribution to grain(AC)of biomass,N,P and K,facilitating greater nutrient transfer to grains and significantly increasing nutrient harvest index.Based on yield and fertilizer use efficiency,this study recommends optimized K application(basal and topdressing 75 kg ha^(-1))and moderate reduction in N application(from 225 to 180 kg ha^(-1))for spring-sown waxy maize production in southern China.
基金funded by the earmarked fund of China Agriculture Research System(CARS-29-10)。
文摘In order to improve the management of nitrogen(N) fertilization in pear orchards, we investigated the effects of application timing on the distribution, storage, and remobilization of N in mature pear trees in a field experiment at Jingtai County, Gansu Province, China. Nine trees were selected for the experiment and each received equal aliquots of 83.33 g N in the autumn, spring, and summer, with ^(15)N-labeled(NH_4)_2SO_4 used in one of the aliquots each season. Results showed that the(^(15)NH_4)_2SO_4 applied in the autumn remained in the soil during the winter. In the following spring this N was absorbed and rapidly remobilized into each organ, especially new organs(leaves, fruit and new shoots). The ^(15)N supplied in spring was rapidly transported to developing fruit between the young fruit and fruit enlargement stages. ^(15)N from the summer application of fertilizer was mainly stored in the coarse roots over the winter, then was mobilized to support growth of new organs in spring. In conclusion, for pear trees we recommend that the autumn application of N-fertilizer be soon after fruit harvest in order to increase N stores in fine roots. Spring application should be between full bloom and the young fruit stages to meet the high N demands of developing fruit. Summer application of fertilizer at the fruit enlargement stage does not contemporaneously affect the growth of pears, but increases the N stored in coarse roots, and in turn the amount available for remobilization in spring.
基金supported by grants from the Ministry of Science and Technology of China(National Key Research and Development Project of China:2016YFC0600308)a Program of the China Geological Survey(DD20160015)NSFC(41702086&41503040)
文摘The Zhaxikang Pb-Zn-Ag-Sb deposit, the largest polymetallic deposit known in the Himalayan Orogen of southern Tibet, is characterized by vein-type mineralization that hosts multiple mineral assemblages and complicated metal associations. The deposit consists of at least six steeply dipping vein- type orebodies that are hosted by Early Jurassic black carbonaceous slates and are controlled by a Cenozoic N-S-striking normal fault system. This deposit records multiple stages of mineralization that include an early period （A） of massive coarse-grained galena-sphalerite deposition and a later period （B） of Sb-bearing vein-type mineralization. Period A is only associated with galena-sphalerite mineralization, whereas period B can be subdivided into ferrous rhodochrosite-sphalerite-pyrite, quartz -sulfosalt-sphalerite, calcite-pyrite, quartz-stibnite, and quartz-only stages of mineralization. The formation of brecciated galena and sphalerite ores during period A implies reworking of pre-existing Pb -Zn sulfides by Cenozoic tectonic deformation, whereas period B mineralization records extensive open- space filling during ore formation. Fluid inclusion microthermometric data indicate that both periods A and B were associated with low-medium temperature （187-267℃） and low salinity （4.00-10.18% wt. NaCl equivalent） ore-forming fluids, although variations in the physical-chemical nature of the period B fluids suggest that this phase of mineralization was characterized by variable water/rock ratios. Microprobe analyses indicate that Fe concentrations in sphalerite decrease from period A to period B, and can be divided into three groups with FeS concentrations of 8.999-9.577, 7.125-9.109, 5.438-1.460 mol.%. The concentrations of Zn, Sb, Pb, and Ag within orebodies in the study area are normally distributed in both lateral and vertical directions, and Pb, Sb, and/or Ag concentrations are positive correlation within the central part of these orebodies, but negatively correlate in the margins. Sulfide S isotope compositions are highly variable （4‰-13‰）, varying from 4‰ to 11‰ in period A and 10‰ to 1‰ in period B. The Pb isotope within these samples is highly radiogenic and defines linear trends in 206pb/204pb vs. 207pb/204pb and 206pb/204pb vs. 208pb/204pb diagrams, respectively. The S and Pb isotopic characteristics indicate that the period B orebodies formed by mixing of Pb-Zn sulfides and regional Sb- bearing fluids. These features are indicative of overprinting and remobilization of pre-existing Pb-Zn sulfides by Sb-bearing ore-forming fluids during a post-collisional period of the Himalayan Orogeny. The presence of similar ore types in the north Rhenish Massif that formed after the Variscan Orogeny suggests that Zhaxikang-style mineralization may be present in other orogenic belts, suggesting that this deposit may guide Pb-Zn exploration in these areas.
基金supported by the Special Fund for Agroscientific Research in the Public Interest in China (201303133, 201203031)the Key Technologies R&D Program of China during the 12th Five-Year Plan period (2011BAD16B14)+1 种基金the Construction of Modern Agricultural Industrial Technology System, Ministry of Agriculture, Chinathe Beijing Higher Education Young Elite Teacher Project, China (YETP0300)
文摘The photosynthetic characteristics of flag leaf and the accumulation and remobilization of pre-anthesis dry mass（DM） and nitrogen（N） in vegetable organs in nine wheat cultivars under different source-sink manipulation treatments including defoliation（DF）, spike shading（SS） and half spikelets removal（SR） were investigated. Results showed that the SS treatment increased the photosynthetic rate（Pn） of flag leaf in source limited cultivar, but had no significant effect on sink limited cultivar. The SR treatment decreased the Pn of flag leaf. Grain DM accumulation was limited by source in some cultivars, in other cultivars, it was limited by sink. Grain N accumulation was mainly limited by source supply. The contribution of pre-anthesis dry mass to grain yield from high to low was stem, leaf and chaff, while the contribution of pre-anthesis N to grain N from high to low was leaf, stem and chaff. Cultivars S7221 and TA9818 can increase the contribution of remobilization of DM and N to grain at the maximum ratio under reducing source treatments, which may be the major reason for these cultivars having lower decrease in grain yield and N content under reducing source treatments.
基金the National Key Research and Development Program of China (2016YFD0300304-4, 2016YFD0300110, 2016YFD0300101)the National Natural Science Foundation of China (31501266)the National Basic Research Program of China (the 973 Program, 2015CB150401) for financial supports
文摘Stay green(SG) maize was found to have higher grain yield and post-silking nitrogen(N) uptake(PostN) compared with a non-stay green(NSG) hybrid. To understand the effects of plant density on grain yield(GY) and N efficiency in modern maize hybrids, we compared two modern hybrids(SG hybrid DY508 and NSG hybrid NH101) with similar maturity ratings at three plant densities(45 000, 60 000, and 75 000 pl ha^–1) in 2014 and 2015. GY, leaf senescence, dry matter(DM) accumulation,N accumulation, PostN, and post-silking N remobilization(RemN) were analyzed. DY508 and NH101 had similar GY, but DY508 had higher thousand kernel weight(TKW) and lower kernel number(KN) than NH101. Plant density significantly increased GY in the two hybrids. On average, over the two years, plant density improved GY in DY508 and NH101 by 18.5 and 11.1%, respectively, but there were no differences in total dry matter(TDM) and post-silking DM(PostDM) between the two hybrids. Plant density improved leaf N, stem N, and grain N at the silking and maturity stages in 2014 and 2015. DY508 was lower in harvest index(HI), nitrogen harvest index(NHI), and grain N concentration(GNC) than NH101. Grain N in DY508 was 2.61 kg ha^–1 less than in NH101, and this was caused by lower GNC and leaf RemN. On the average, DY508 was 1.62 kg ha^–1 less in leaf remobilized N(leaf RemN) than NH101, but was similar in stem remobilized N(stem RemN;2.47 kg ha^–1 vs. 3.41 kg ha^–1). Maize hybrid DY508 shows delayed leaf senescence in the upper and bottom canopy layers in the later stages of growth. The present study provides evidence that the NH101, which has rapid leaf senescence at the late grain-filling stage, has gained equivalent GY and higher leaf RemN, and was more efficient in N utilization.
基金supported by the National Natural Science Foundation of China(31971860).
文摘Foliar nitrogen(N)application is an effective strategy to improve protein content and quality in wheat kernels,but the specific effects of N forms remain unclear.In a two-year field study,foliar application of various N forms(NO_(3)^(-),urea,NH_(4)^(+))at anthesis was performed to measure their effects on wheat grain protein accumulation,quality formation,and the underlying mechanisms.Foliar application of three N forms showed varying effects in improving grain gluten proteins and quality traits.Under NH_(4)^(+) application,there was more post-anthesis N uptake for grain filling,with relatively strong increase in enzyme activities and gene expression associated with N metabolism in flag leaves at 8–20 days after anthesis(DAA),whereas its promotion of grain N metabolism became weaker after 20 DAA than those under NO_(3)^(-) and urea treatments.More N was remobilized from source organs to grain under treatment with foliar NO_(3)^(-) and urea.Genes controlling the synthesis of gluten protein and disulfide bonds were upregulated by NO_(3)^(-) and urea at 20–28 DAA,contributing to increased grain protein content and quality.Overall,foliar applications of NO_(3)^(-) and urea were more effective than those of NH_(4)^(+) in increasing grain N filling.These findings show that manipulating the source–sink relationship by reinforcing grain N metabolism and N remobilization is critical for optimizing grain protein accumulation and quality formation.
基金financially supported by the National Key Research and Development Program of China(2017YFD0200200,2017YFD0200202)the National Natural Science Foundation of China(31960627)+1 种基金support from the Australia-China Joint Research Centre-Healthy Soils for Sustainable Food Production and Environmental Quality(ACSRF48165)the CSIRO and Chinese Academy of Agricultural Sciences(CAAS)through the research project"Scientific Benchmarks for Sustainable Agricultural Intensification"for financial support。
文摘Maize growth,organ development,and yield formation are highly controlled by the manner in which the plant captures,partition,and remobilizes biomass and phosphorus(P).Better understanding of biomass and P accumulation,partition,and remobilization processes will improve modeling of crop resource use.However,there is still a lack of detailed data to parameterize the modeling of these processes,particula rly for modern maize cultivars.A two-year(2016 and 2017)field experiment with three P fertilization treatments(0(P0),75(P75),and 300(P300)kg P_(2)O_(5)ha^(-1))was conducted on a Fluvo-aquic soil(Quzhou,Hebei province,China)to collect data and quantify key processes for a representative modern maize cultivar(Zhengdan 958)widely grown in China.The proportions of biomass and P partitioned into various maize organs were unaffected by P application rate.Zhengdan 958 showed a much lower leaf-senescence rate than older cultivars,resulting in post-silking leaf photosynthesis being sufficient to meet grain biomass demand.In contrast,50%-85%of leaf P and 15%-50%of stem P accumulated pre-silking were remobilized into grain,in spite of the large proportion of post-silking P uptake.Our results are consistent with the theory that plants use resources according to the priority order of re-allocation from senescence followed by assimilation and uptake,with the re-translocation of reserves last.The results also enabled us to estimate the threshold P concentrations of Zhengdan 958 for modeling crop P demand.The critical leaf P concentration for individual leaves was 0.25%-0.30%,with a corresponding specific leaf P(SLP)of 75-100 mg P m^(-2).The structural P concentration for leaf was 0.01%,corresponding to an SLP of 3.8 mg P m^(-2).The maximum P concentrations of leaves and stems were 0.33%and 0.29%.The residual P concentration for stems was 0.006%.
基金financially supported by the National Basic Research Program of the People's Republic of China(Nos.2013CB429801,2006CB403500)the National Natural Science Foundation of China(Nos.40972057,41502069)the Postdoctoral Science Foundation of China(No.2015M570033)
文摘The genesis of the giant Dongshengmiao in the northern margin of the North China Block has been debated since its discovery in the 1950 s,because it shows geological and geochemical characteristics with both syngenetic and epigenetic signatures.It has geological settings and sulfur and lead isotopic compositions that are similar with typical SEDEX（sedimentary exhalative） deposit,while the Zn-Pb-Cu mineralization was controlled by shear deformation and metamorphism,showing similarities with orogenic-type deposits.In this contribution,both the syngenetic and epigenetic features of the Dongshengmiao are envisaged,and accounted for in the context of a genetic model with two metallogenic periods.Massive pyrite at the Dongshengmiao was mostly recrystallized during metamorphism,but finegrained texture was locally preserved,indicating its syngenetic origin.On the contrary,all the Zn-Pb-Cu ores observed in this study show characteristics of epigenetic hydrothermal mineralization that controlled by metamorphism and accompanying shear deformation.The sulfur and lead isotopic compositions of sphalerite and galena indicate that they were in situ remobilized from a syngenetic stratabound source,and the oxygen and hydrogen isotopic ratios of ore-fluid indicate that the large-scale remobilization was assisted by metamorphic fluid.The thermodynamic modeling indicates that the orefluid during remobilization has a great potential of transporting Cu.This may account for the abnormally enriched Cu in the remobilized SEDEX deposit.The metamorphic fluid might strip Cu from the fluid source during devolatilization,and overprint it on the Zn-Pb orebodies during remobilization.A secondary flowthrough modeling reveals that Zn- and Cu-sulfides would be preferentially redistributed in Fe-rich carbonates during remobilization,as a result of fluid-rock interaction.Conclusively,a multistage genetic model is proposed.During the development of the Proterozoic rift,stratabound Zn-Pb mineralization took place in a SEDEX ore-forming system.The syngenetic sulfides subsequently underwent a large-scale fluidassisted remobilization during the early Cretaceous metamorphism and thrusting,forming the shear zone-controlled epigenetic orebodies.During the remobilization process,Cu was scavenged from the source of metamorphic fluid,and deposited accompanying remobilized Zn-Pb sulfides.Shear structures and Fe-rich carbonates are ideal sites for redistribution and re-deposition of remobilized sulfide.
基金supported by the National Key Research and Development Program of China(2017YFD0200204)the National Natural Science Foundation of China(31972496,31572190)+1 种基金the Deutsche Forschungsgemeinschaft(328017493/GRK2366)the National Institutes of Health Grant(R15 GM 104876)to Jana Patton-Vogt。
文摘Phosphate deficiency is one of the leading causes of crop productivity loss.Phospholipid degradation liberates phosphate to cope with phosphate deficiency.Glycerophosphodiester phosphodiesterases(GPX-PDEs)hydrolyse the intermediate products of phospholipid catabolism glycerophosphodiesters into glycerol-3-phosphate,a precursor of phosphate.However,the function of GPX-PDEs in phosphate remobilization in maize remains unclear.In the present study,we characterized two phosphate deficiency-inducible GPX-PDE genes,ZmGPX-PDE1 and ZmGPX-PDE5,in maize leaves.ZmGPX-PDE1 and ZmGPX-PDE5 were transcriptionally regulated by ZmPHR1,a well-described phosphate starvation-responsive transcription factor of the MYB family.Complementation of the yeast GPX-PDE mutant gde1Δindicated that ZmGPX-PDE1 and ZmGPX-PDE5 functioned as GPX-PDEs,suggesting their roles in phosphate recycling from glycerophosphodiesters.In vitro enzyme assays showed that ZmGPX-PDE1 and ZmGPX-PDE5 catalysed glycerophosphodiester degradation with different substrate preferences for glycerophosphoinositol and glycerophosphocholine,respectively.ZmGPX-PDE1 was upregulated during leaf senescence,and more remarkably,loss of ZmGPXPDE1 inmaize compromised the remobilization of phosphorus fromsenescing leaves to young leaves,resulting in a stay-green phenotype under phosphate starvation.These results suggest that ZmGPX-PDE1 catalyses the degradation of glycerophosphodiesters in maize,promoting phosphate recycling from senescing leaves to new leaves.This mechanism is crucial for improving phosphorus utilization efficiency in crops.
文摘Winter jujube orchard nitrogen （N） management aims at increasing N reserves to meet the tree＇s growth requirements. Fertilization strategies should maximize the efficiency of fertilizers, including the choice of the optimal timing of N supply. ^15N-urea was applied to winter jujubes on Jinsixiaozao jujubes rootstock to evaluate the effect of application timing on Nstorage and remobilization in mature trees in pot culture. The treatments consisted of ground application before budding （BB）, during fruit core-hardening stage （FCH）, and fruit rapid-swelling stage （FRS）. Nitrogen-use efficiency of treatments were significantly different, which were 2.42% （BB）, 9.77% （FCH）, and 9.01% （FRS） in the dormant and 5.20% （BB）, 16.16% （FCH）, and 10.30% （FRS） in the following full-bloom. N supply in the pre-harvest helped to increase N-reserves of trees and then translocate to the new growth organs the following year. The largest amount of ^15N was detected in the roots and trunks. In all the treatments, the partition rates were highest in coarse roots, which were 30.43% （BB）, 38.61% （FCH）, and 40.62% （FRS）, respectively. ^15N stored in roots and trunks was used by jujube trees to sustain new growth in the following full-bloom. ^15N applied before budding resulted in lower Ndff% in perennial organs （trunks and coarse roots） sampled in the following full-bloom, but fine roots had highest Ndff% （1.28%）. Other organs recovered similar amount of Ndff%. In contrast, FCH and FRS treatments led to higher Ndff% （4.01-5.15%） in the new growth organs （new growth branches, deciduous spurs, leaves and flowers）, but lower Ndff% in perennial branches （1.49-2.89%）. With the delay of ^15N-urea application time, ^15N increased the partitioning to roots. FCH treatment increased N-storage in perennial organ during winter, which should be remobilized to sustain new growth the following spring.
基金This study was supported by the Foundation for Distinguished Young Scholars of Jiangsu Province,China(Grant No.BK20190050)Youth Innovation Promotion Association of Chinese Academy of Sciences(Grant No.2015250)+2 种基金the‘Strategic Priority Research Program’of the Chinese Academy of Sciences(Grant No.XDB15030300)National Science Foundation of China(Grant No.31501825)the State Key Laboratory for Conservation and Utilization of Subtropical Agro-bioresources in China in 2020(Grant No.SKLCUSA-b201909).
文摘Pectin contributes greatly to cell wall phosphorus(P)remobilization.However,it is currently unclear whether the methylesterification degree of the pectin,which is related to the activity of pectin methylesterases(PMEs),is also involved in this process.Here,we demonstrated that elevated PME activity can facilitate the remobilization of P deposited in the cell wall.P-deficient conditions resulted in the reduction of root cell wall P content.This reduction was more pronounced in Nipponbare than in Kasalath,in company with a significant increment of the PME activity,indicating a possible relationship between elevated PME activity and cell wall P remobilization.This hypothesis was supported by in vitro experiments,as pectin with lower methylesterification degree had higher ability to release inorganic P(Pi)from insoluble FePO_(4).Furthermore,among the 35 OsPME members in rice,only the expression of OsPME14 showed a relationship with PME activity.In addition,transgenic rice lines overexpressing OsPME14 had increased PME activity,released more P from the root cell wall,and more resistant to P deficiency.In conclusion,PMEs enhance P remobilization in P-starved rice by increasing PME activity in Nipponbare,which in turn helps to remobilize P from the cell wall,and thus makes more available P.
基金Supported by the Special Fund for Agro-scientific Research in Public Interest in China(201503119-06-01)。
文摘Slope farmland is a main type of agricultural land throughout northeast China.Long-term high intensity utilization and unreasonable farming have caused the deterioration of soil resources and a decrease in crop production.Here,it was hypothesized that crop straw incorporation might help to reduce nutrient losses and increase maize yields across time and space.A field experiment for testing straw management practices on maize across three slope positions(top,back and bottom slopes)was conducted in Northeast China in 2018 and 2019.In this study,the dry matter accumulation(DMA),N accumulation(NA),N remobilization,postsilking N uptake and grain yield were measured under SI(straw incorporation)and NSI(no straw incorporation)across three slope positions of 100-m-long consecutive black soil slope farmland during the maize(Zea mays L.)growth stages.Compared with NSI,SI significantly increased DMA and NA at the silking and maturity stages.SI typically increased the N remobilization in all slope positions,and significantly increased N remobilization efficiency and contribution of N remobilization to grain on the back and bottom slopes.However,post-silking N uptake was only increased by SI on the top slope.SI generally increased the crop yield in three slope positions.In the SI treatments,the bottom slope was the highest yield position,followed by the top,and then the back slopes,suggesting that the bottom slope position of regularly incorporated straw might have increased the potential for boosting maize yield.Overall,the study demonstrated the outsized potential of straw incorporation to enhance maize NA and then increase the grain yield in black soil slope farmland.
基金supported by grants from the National Key Research and Development Program of China(2021YFF1000501 and 2022YFD1900704)National Natural Science Foundation of China(32070306,32172667,and U23A20178)+2 种基金the Chinese Universities Scientific Fund(2023RC015)the 2115 Talent Development Program of China Agricultural Universitythe Central PublicInterest Scientific Institution Basal Research Fund(Y2022QC14)。
文摘Phosphorus(P)is an essential macronutrient for plant growth and development.Vacuoles play a crucial role in inorganic phosphate(Pi)storage and remobilization in plants.However,the physiological function of vacuolar phosphate efflux transporters in plant Pi remobilization remains obscure.Here,we identified three Zm VPE genes(ZmVPE1,ZmVPE2a,ZmVPE2b)by combining them with transcriptome and quantitative real-time polymerase chain reaction(PCR)analyses,showing a relatively higher expression in older leaves than in younger leaves in maize.Moreover,the expression of the ZmVPEs was triggered by Pi deficiency and abscisic acid.ZmVPEs were localized to the vacuolar membrane and responsible for vacuolar Pi efflux.Compared with the wild-type,Pi remobilization from older to younger leaves was enhanced in Zm VPE-overexpression lines.zmvpe2a mutants displayed an increase in the total P and Pi concentrations in older leaves,but a decrease in younger leaves.In rice,Pi remobilization was impaired in the osvpe1osvpe2 double mutant and enhanced in OsVPE-overexpression plants,suggesting conserved functions of VPEs in modulating Pi homeostasis and remobilization in crop plants.Taken together,our findings revealed a novel mechanism underlying Pi remobilization from older to younger leaves mediated by plant vacuolar Pi efflux transporters,facilitating the development of Pi-efficient crop plants.
基金the Ministry of Education, Science, Sports and Culture (MEXT),Japan.
文摘Translocation of absorbed phosphorus （P） from metabolically inactive sites to active sites in plants growing under P deprivation may increase its P utilization efficiency （PUE）. Acclimation to phosphate （Pi） starvation may be caused by a differential storage pool of vacuolar P, its release, and the intensity of re-translocation of absorbed P as P starvation inducible environmental cues （PSlEC） from ambient environment. Biomass assay and three P forms, namely inorganic （Pi）, organic （Po）, and acid-soluble total （Ptas） were estimated in Brassica cultivars exposed to 10 d P deprivation in the culture media. Considering that -aPi/at denotes the rate of Pi release, Pi release velocity （RSPi） was determined as the tangent to the equations obtained for Pi f（t） at the mean point in the period of greatest Pi decrease, whereas the inverse of the RSPi was an estimate of the internal Pi buffering capacity （IBCPi）. Inter cultivar variations in size of the non-metabolic Pi pool, RSPi, re-translocation of Pi from less to more active metabolic sites, and preferential Pi source and sink compartments were evaluated under P starvation. The cultivar ＇Brown Raya＇ showed the highest Pi storage ability under adequate external P supply, and a more intensive release than ＇Rain Bow＇ and ＇Dunkled＇ under P stress. Cultivar ＇B.S.A＇ was inferior to ＇Con-l＇ in its ability to store and use Pi. Roots and upper leaves were the main sink of Pi stored in the lower and middle leaves of all cultivars and showed lower IBCPi and larger RSPi values than lower and middle leaves. In another trial, six cultivars were exposed to P-free nutrition for 29 d after initial feeding on optimum nutrition for 15 d. With variable magnitude, all of the cultivars re-translocatad P from the above ground parts to their roots under P starvation, and [P] at 44 d after transplanting was higher in developing leaves compared with developed leaves. Under P deprivation, translocation of absorbed P from metabolically inactive to active sites may have helped the tolerant cultivars to establish a better rooting system, which provided a basis for tolerance against P starvation and increased PUE. A better understanding of the extent to which changes in the flux of P absorption and re-translocation under PSIEC will help to scavenge Pi from bound P reserves and will bring more sparingly soluble P into cropping systems and obtain capitalization of P reserves.
基金the Zhejiang Provincial Natural Science Foundation of China(grant LZ23C020001 to K.Z.)the National Natural Science Foundation of China(grant 31670277 to K.Z.).
文摘Monocarpic senescence,characterized by whole-plant senescence following a single flowering phase,is widespread in seed plants,particularly in crops,determining seed harvest time and quality.However,how external and internal signals are systemically integrated into monocarpic senescence remains largely unknown.Here,we report that the Arabidopsis thaliana transcription factor WRKY1 plays essential roles in multiple key steps of monocarpic senescence.WRKY1 expression is induced by age,salicylic acid(SA),and nitrogen(N)deficiency.Flowering and leaf senescence are accelerated in the WRKY1 overexpression lines but are delayed in the wrky1 mutants.The combined DNA affinity purification sequencing and RNA sequencing analyses uncover the direct target genes of WRKY1.Further studies show that WRKY1 coordinately regulates three processes in monocarpic senescence:(1)suppressing FLOWERING LOCUS C gene expression to initiate flowering,(2)inducing SA biosynthesis genes to promote leaf senescence,and(3)activating the N assimilation and transport genes to trigger N remobilization.In summary,our study reveals how one stress-responsive transcription factor,WRKY1,integrates flowering,leaf senescence,and N remobilization processes into monocarpic senescence,providing important insights into plant lifetime regulation.
文摘Japan has a limited amount of readily developable land.Sites are used and reused with alternating phases of excavation and deposition of man-made strata(MMS).The Great East Japan earthquake of 11th March 2011 caused widespread damage due to ground waves and associated liquefaction-fluidization of MMS.A site at Kamisu City,Ibaraki Prefecture,was significantly affected.There,a gravel pit had been filled,partly excavated and then refilled.In 2003 it was found that a nearby drinking water well was seriously contaminated with arsenic.The site was sampled using a grid of boreholes and then excavated within a sheet pile enclosure at the source of the arsenic.The pollution came from large blocks that had been made by mixing cement with DiPhenylArsinic Acid powder and wastes that had been illegally dumped during refilling.The blocks were excavated and removed.Contaminated groundwater was pumped out and purified and the excavation was filled.
基金supported by the‘Double First-Class’Key Scientific Research Project of Education Department in Gansu Province,China(GSSYLXM-02)the National Natural Science Foundation of China(U21A20218 and 32160765)+3 种基金the earmarked fund for China Agriculture Research System(CARS-22-G-12)the Science and Technology Project of Gansu Province,China(20JR5RA037 and 21JR7RA836)the Postdoctoral Research Start-up Foundation of Gansu Province,China(03824034)the Postdoctoral Research Start-up Foundation of Gansu Agricultural University,China(202403)。
文摘A critical challenge for global food security and sustainable agriculture is enhancing crop yields while reducing chemical N inputs.Improving N use efficiency in crops is essential for increasing agricultural productivity.The aim of this study was to evaluate the impacts of intercropping maize with leguminous green manure on grain yield and N utilization under reduced N-fertilization conditions.A field experiment with a split-plot design was conducted in northwestern China from 2018 to 2021.The main plots consisted of two cropping systems:maize-common vetch intercropping(IM)and sole maize(SM).The subplots had three N levels:zero N application(N0,0 kg ha^(-1)),a 25%reduction from the traditional chemical N supply(N1,270 kg ha^(-1)),and the traditional chemical N supply(N2,360 kg ha^(-1)).The results showed that the negative effects of N reduction on maize grain yield and N uptake were compensated by intercropping leguminous green manure,and the improvements increased with cultivation years.The integrated system involving maize-leguminous green manure intercropping and a reduced N supply enhanced N translocation from maize vegetative organs to grains and increased the nitrate reductase and glutamine synthetase activities in maize leaves.The supercompensatory effect in maize leaves increased year by year,reaching values of 16.1,21.3,and 25.5%in 2019,2020,and 2021,respectively.These findings suggest that intercropping maize with leguminous green manure under reduced chemical N input can enhance N assimilation and uptake in maize.By using this strategy,chemical fertilizer is effectively replaced by leguminous green manure,thereby improving N use efficiency and maintaining stable yields in the maize-based intercropping system.
基金Supported by National Key Technology Research and Development Program(2012BAD04B09,2013BAD07B08)
文摘This study aimed to analyze the absorption, utilization and transfer char- acteristics of nitrogen in high-yield winter wheat （Triticum aestivum） cultivars at dif- ferent sowing dates, so as to determine the optimum sowing dates for different high-yield wheat cultivars. A field experiment was conducted in the Shajiang black soil of Anhui Province with Jimai 22, Wanrnai 52 and Zhoumai 22, and the effects of early sowing （October 3）, optimum sowing （October 12） and late sowing （October 30） on wheat plant N content and accumulation, pre-and post-anthesis N accumula- tion （NA） of total plant, nitrogen remobUization to grain （NR）, N remobilization effi- ciency （NRE）, contribution of N remobilized to grain （NRC）, grain yield, N use effi- ciency （NUE） and N harvest index （NHI） of different wheat cultivar were investigat- ed. The results showed that sowing date had an impact on N content, absorption and utilization in wheat plants at various growth stages. The NA, NR and NRC of aboveground vegetative organs of wheat before anthesis were higher than those af- ter anthesis. Under the condition of late sowing, the grain N accumulation mainly depended on the N absorption by vegetative organs before anthesis. Under the conditions of optimum and early sowing, the absorbed N after anthesis accounted for a large proportion in grain N accumulation. The N uptake intensity and relative cumulative rate differed greatly among different growth stages and different-genotype wheat cultivars, and the pre-anthesis NA, pre-anthesis NR, pre-anthesis NRE, post- anthesis N assimilation amount and post-anthesis NRC showed significant differ- ences among different wheat cultivars. The grain yields of different wheat cultivars under the early and optimum sowing were all higher than those under the late sowing. The NHI and grain N accumulation were highest under the optimum sow- ing, and the latter significantly decreased with the delay of sowing dates. In con- trast, the NUE was highest under the late sowing, reaching 35.95%-41.32%. It indi- cated that under the condition of late sowing, most of the nitrogen was not ab- sorbed by wheat, but the use efficiency of the absorbed nitrogen significantly in- creased. In overall, the three high-yield wheat cultivars were all suitable for early and optimum sowing. Under the condition of late sowing, the yield of Zhoumai 22 showed the smallest differences with those under early and optimum sowing, and its NUE was significantly improved. Therefore, among the three high-yield wheat culti- vars, Zhoumai 22 was most suitable for late sowing.
基金supported by the National Key Research and Development Program of China (2016YFD0300401)the National Natural Science Foundation of China (32001474, 31871563)the China Agriculture Research System (CARS-3)。
文摘Increased grain yield(GY) and grain protein concentration(GPC) are the two main targets of efforts to improve wheat(Triticum aestivum L.) production in the North China Plain(NCP). We conducted a three-year field experiment in the 2014–2017 winter wheat growing seasons to compare the effects of conventional irrigation practice(CI) and micro-sprinkling irrigation combined with nitrogen(N) fertilizer(MSI) on GY, GPC, and protein yield(PY). Across the three years, GY, GPC, and PY increased by 10.5%–16.7%, 5.4%–8.0%, and 18.8%–24.6%, respectively, under MSI relative to CI. The higher GY under MSI was due primarily to increased thousand-kernel weight(TKW). The chlorophyll content of leaves was higher under MSI during the mid–late grain filling period, increasing the contribution of post-anthesis dry matter accumulation to GY, with consequent increases in total dry matter accumulation and harvest index compared to CI. During the mid–late grain filling period, the canopy temperature was markedly lower and the relative humidity was higher under MSI than under CI. The duration and rate of filling during the mid–late grain filling period were also higher under MSI than CI, resulting in higher TKW. MSI increased the contribution of post-anthesis N accumulation to grain N but reduced the pre-anthesis remobilization of N in leaves, the primary site of photosynthetic activity, possibly helping maintain photosynthate production in leaves during grain filling. Total N at maturity was higher under MSI than CI,although there was little difference in N harvest index. The higher GPC under MSI than under CI was due to a larger increase in grain N accumulation than in GY. Overall, MSI simultaneously increased both GY and GPC in winter wheat grown in the NCP.
基金Supported by the Special Fund for Agro-scientific Research in the Public Interest(No.200903001-5)the Priority Academic Program Development of Jiangsu Higher Education Institutions(PAPD)of China+1 种基金the Natural Science Foundation of Jiangsu Province,China(No.BK2010440)China Postdoctoral Science Foundation(No.20110491439)
文摘Ammonium(NH+4) is the main nitrogen(N) form for rice crops, while NH+4near the root surface can be oxidized to nitrate(NO-3)by NH+4-oxidizing bacteria. Nitrate can be accumulated within rice tissues and reused when N supply is insufficient. We compared the remobilization of NO-3stored in the tissue and vacuolar between two rice(Oryza sativa L.) cultivars, Yangdao 6(YD6, indica)with a high N use efficiency(NUE) and Wuyujing 3(WYJ3, japonica) with a low NUE and measured the uptake of NO-3, expression of nitrate reductase(NR), NO-3transporter genes(NRTs), and NR activity after 4 d of N starvation following 7-d cultivation in a solution containing 2.86 mmol L-1NO-3. The results showed that both tissue NO-3concentration and vacuolar NO-3activity were higher in YD6 than WYJ3 under N starvation. YD6 showed a 2- to 3-fold higher expression of OsNRT2.1 in roots on the 1st and 4th day of N starvation and had significantly higher values of NO-3uptake(maximum uptake velocity, Vmax) than the cultivar WYJ3.Furthermore, YD6 had significantly higher leaf and root maximum NR activity(NRAmax) and actual NR activity(NRAact) as well as stronger root expression of the two NR genes after the 1st day of N starvation. There were no significant differences in NRAmax and NRAact between the two rice cultivars on the 4th day of N starvation. The results suggested that YD6 had stronger NRA under N starvation, which might result in better NO-3re-utilization from the vacuole, and higher capacity for NO-3uptake and use, potentially explaining the higher NUE of YD6 compared with WYJ3.
