phosphorus

摘要： 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.

摘要： [Objectives]This study was conducted to explore the rational formula for rice fertilization in Jianghan Plain.[Methods]An experiment on the combined application of nitrogen,phosphorus and potassium fertilizers was carried out in Jianghan Plain,an important rice producing area in Hubei,with a total of five treatments to study the effects of nitrogen,phosphorus and potassium fertilizers on the fertilizer use efficiency and yield of rice.[Results]Fertilization had a significant effect on improving rice yield,and nitrogen fertilizer had the greatest effect on rice yield,followed by potassium fertilizer and phosphorous fertilizer.[Conclusions]This study provides a scientific basis for the application of rice fertilizers and the reduction and efficiency improvement of chemical fertilizers in Jianghan Plain.

摘要： Phosphorus (P) released and transported from wetlands affects wetland ecosystems and surrounding water systems. Sediment samples from the Pelham Bay wetlands in the Bronx, NY, have been collected and analyzed. Analysis of the sorption characteristics, P compound identification and P mineralization, showed significant correlations between the sorption maximum (Smax) and Ox-Fe (r = 0.894), ash-TP and HCl-Ca (r = 0.94), ash-TP and TOC (r = 0.96), as well as TOC vs HCl-Ca (r = 0.93). These results indicate that mineral content affects the OP content and the sorption process. P sorption maxima Smax ranged from 70.4 to 1667 mg/Kg, and the equilibrium P concentration EPC0 ranged from 0.09 to 0.2 mg/L. The high Smax in most of the sites, fairly high EPC0 and high percentages of Pr (>96%), indicate substantial amounts of P could be bioavailable for plant uptake in the water column under changing hydro-climatic conditions. Dominant P compounds are dihydroxyacetone phosphate (DHAP), phosphoenolpyruvates (PEP), inosine monophosphate (IMP), glucose-6-phosphate (G6P), nucleoside monophosphates (NMP), glycerophosphate (GlyP), polynucleotides (PolyN), and pyrophosphates (Pyrop). The active P pool could maintain substantial P bioavailability and potentially cause eutrophication. The mineralization of 7, 15 and 30 days in laboratory experiments indicates a decrease of NaHCO3 and HCl, and an increase of NaOH.

摘要： Multi-element analysis in historical sites is a major issue in archaeological studies;however,this approach is almost unknown among Iranian scholars.Geochemical multi-element analysis of soil is very important to evaluate anthropogenic activities.The aim of this study consists of assessing the potential usefulness of multi-elemental soil analysis,obtained by Analytical Jena atomic absorption spectrophotometer(AAS) and ICP-MS,to recognize ancient anthropogenic features on the territory of Tappe Rivi(North Khorasan,Iran).For that purpose,a total of 80 ancient soil samples were sampled from each soil horizon and cultural layer.The research involved Fe,Al,Cd,Cu,Ni,Co,Cr,Pb,and P which trace element samples were extracted according to the International Standard ISO 11466 and phosphorus samples by Olsen method.Besides,the contamination of the soils was assessed based on enrichment factors(EFs) by using Fe as a reference element.This geochemical/archaeological approach highlights that the content of most elements in the Parthian and Sassanid ages were significantly higher than the contents of the elements in other zones,which shows that by the development of the eras,the content of the elements has also increased.Also,the accumulation of metals in the Rivi site was significantly higher than in the control area.Among the sampled zones,enrichment factor(EF) indicated that the enrichment of Cu and phosphate at the Parthian and Sassanid had the highest content.This result is important because it shows that the amount of metals and human activities are directly related to each other during different ages.

摘要： Dinofl agellates are the major causative agents of harmful algal blooms in the global ocean and they usually form blooms under conditions of very low dissolved inorganic phosphorus(DIP).However,the mechanisms underpinning the dinofl agellate blooms remain unclear.Here,we quantitatively compared protein expression profi les of a marine dinofl agellate,Prorocentrum donghaiense,grown in inorganic P-replete,P-defi cient,and DIP-and dissolved organic phosphorus(DOP)-resupplied conditions by employing a Tandem Mass Tag(TMT)-based quantitative proteomic approach.Proteins involved in intracellular P reallocation,organic P,and non-P lipid utilization were up-regulated under the P-defi cient condition,while inorganic phosphate transporters varied insignifi cantly.In response to the P resupplementation,nitrogen metabolism,ribosome,porphyrin,and chlorophyll metabolism were up-regulated,while lysosome,and starch and sucrose metabolism were down-regulated.Notably,photosynthesis was up-regulated and secondary metabolism was down-regulated only in the DIP-resupplied cells,whereas amino acid metabolism and vitamin B6 metabolism were up-regulated in the DOP-resupplied cells,indicating diff erential response mechanisms of P.donghaiense to DIP or DOP resupplementation.Our results indicated that P.donghaiense initiated multiple strategies in response to an ambient inorganic P-defi ciency,and its efficient DOP assimilation by providing both P and carbon sources might be a key factor driving bloom formations of P.donghaiense in a low DIP environment.

摘要： Graphene has raised a huge wave in 2D materials field,breeding lots of graphene analogs with applications in optical and electrical devices,energy conversion and storage,bio-logy,etc.[1,2].Graphene presents superior carrier mobility,while its zero-bandgap restricts its transistor application.To make up this shortcoming,new 2D materials with certain bandgaps and high carrier mobility are being developed.Two typical materials are transition metal dichalcogenides(TMDs)and black phosphorus,which exhibit layered structure,layer-dependent band structure and strong quantum con-straints[3−5].As a congener of phosphorus,arsenic can complement the bandgap of existed 2D materials[6−18].

摘要： Background:Phosphorus is essential for bone mineralization in broilers,however,the underlying mechanisms remain unclear.We aimed to investigate whether bone phosphorus retention and bone development might be regulated by related hormones and local bone-derived regulators in broilers.Methods:Broilers were fed diets containing different levels of non-phytate phosphorus(NPP)0.15%,0.25%,0.35%,0.45% and 0.55% or 0.15%,0.22%,0.29%,0.36% and 0.43% from 1 to 21 or 22 to 42 days of age.Serum and tibia samples were collected for determinations of bone phosphorus retention and bone development parameters,related hormones and local bone-derived regulators of broiler chickens on d 14,28 and 42,respectively.Results:Tibia ash phosphorus,total phosphorus accumulation in tibia ash(TP_(TA)),bone mineral concentration(BMC),bone mineral density(BMD),bone breaking strength(BBS),and ash on d 14,28 or 42,serum 1,25-dihydroxyvitamin D_(3)(1,25(OH)_(2)D_(3))on d 28 and 42,mRNA expressions of tibia fibroblast growth factor 23(FGF23)and dentin matrix protein 1(DMP1)on d 14 and 28 increased linearly or quadratically(P<0.05),while serum parathyroid hormone(PTH)on d 28,tibia alkaline phosphatase(ALP)on d 14,28 and 42,bone gal protein(BGP)on d 14,and mRNA expression of tibia phosphate-regulating gene with homologies to endopeptidases on the X chromosome(PHEX)on d 14 and 28 decreased linearly or quadratically(P<0.04)as dietary NPP level increased.TPTA,BMC,BMD,and ash on d 28 and 42,BBS on d 28,and ash phosphorus on d 42 were positively correlated(r=0.389 to 0.486,P<0.03)with serum 1,25(OH)_(2)D_(3).All of the above parameters were positively correlated(r=0.380 to 0.689,P<0.05)with tibia DMP1 mRNA expression on d 14,28 and 42,but negatively correlated(r=−0.609 to−0.538,P<0.02)with serum PTH on d 28,tibia ALP on d 14,28 and 42,and BGP on d 14.TP_(TA),BMC and ash on d 14 and BMD on d 28 were negatively correlated(r=−0.397 to−0.362,P<0.03)with tibia PHEX mRNA expression,and BMD on d 28 was positively correlated(r=0.384,P=0.04)with tibia FGF23 mRNA expression.Conclusions:These results suggested that bone phosphorus retention and bone development parameters had moderate to strong correlations with serum PTH and 1,25(OH)2D3 and tibia DMP1,PHEX,FGF23,ALP and BGP in broilers during the whole growth period,and thus they might be partly regulated by these related hormones and local bone-derived regulators.

摘要： 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%.

摘要： Thailand rosewood(Dalbergia cochinchinensis)is a vulnerable high value tree species in subtropical and tropical Southeast Asia.The demand for the rehabilitation of the natural habitat of the species requires high-quality seedlings.However,current fertilizer regimes tend to deliver a coarse rate of fertilizers that result in a low uptake efficiency and a high risk of nutrient excess.Exponential fertilization is an effective approach to promote seedling quality through identifying an optimum dose out of a range of applications.In this study,Thailand rosewood seedlings were cultured in a mixed substrate of perlite,vermiculite,and peat(2:2:3,v/v/v)and received exponential fertilization from 0(control),through 100,200,300,400,and 600 mg nitrogen(N)per plant over a four-month cultural rotation.Height,diameter,and shoot biomass increased with fertilizer rate and were maximized at 300 mg N per plant.This application also reduced nutrient deficiencies and avoided excess supply compared to higher rates.Polysaccharide,proline,and anti-oxidation enzyme activities tended to be greater in unfertilized controls or in over-fertilized high dosages,with lower activities around 100–300 mg N plant~(-1).Application of 300 mg N per plant was identified as the optimum dosage as it maximized nutrient reserves,polysaccharide and proline contents,and anti-oxidants without causing any symptoms from excess fertilizer toxicity.Future work is required to identify the effects of N-fixation on the formation of nutritional reserves in Thailand rosewood seedlings subjected to exponential fertilization.

摘要： In arid and semi-arid regions, the growth and development of cultivated plants, especially tomato (Solanum lycopersicum L.), are severely limited by water deficit. Thus, to cope with this constraint, the plant establishes symbiotic relationships with arbuscular mycorrhizal fungi (AMF) in the soil whose extension of the hyphae allows a better and deeper exploration;this notably improves the hydromineral nutrition of the plant. Therefore, the choice of fungal partner becomes crucial for the establishment of a crop in water-deficient soil. In this context, the contribution of AMF to the water stress tolerance of two varieties of tomato plants was assessed under semi-controlled conditions. Parameters, such as the mycorrhizal frequency, intensity of mycorrhization, relative mycorrhizal dependency, growth, and biochemical parameters (carbon, nitrogen, phosphorus, and proline contents) of plants subjected to three levels of water stress (T100, T70, and T30), were evaluated. The highest frequencies and intensities of mycorrhization and relative mycorrhizal dependencies were obtained with plants of the Xewel variety inoculated with Rhizophagus fasciculatus (F: 95.24%, 88.35%, and 13.64%;M: 40.52%, 37.52%, and 11.22%;D: 23.7%, 54.4%, and 78.82%) and in those of the Lady Nema variety inoculated with Claroideoglomus etunicatum (F: 95.12%, 87.01%, and 15.25%;M: 40.66%, 37.99%, and 11.42%;D: 19.27%, 57.01%, and 70.98%), respectively at water regimes of T100, T70 and T30. These same symbiotic couples recorded, at T30, the best survival rates (+ 40%) and the higher aerial (77% and 74%) and root dry weights (80% and 59%). Plants of the Xewel variety inoculated with R. fasciculatus recorded the highest contents of carbon (T70: 30.59% and T30: 21.55%) and phosphorus (T70: 0.18% and T30: 0.17%). Plants of the Lady Nema variety recorded the highest nitrogen contents with 3.51% and 3.20%, respectively at T70 and T30. Plants of the Lady Nema variety, inoculated with C. etunicatum, also recorded the highest proline contents (572.25, 739.44, and 1165 nmoles•g−1 of fresh material), followed by those of the Xewel variety inoculated with R. fasciculatus (580.36, 763.65, and 1112.11 nmoles•g−1 of fresh matter), respectively at T100, T70, and T30. For the Lady Nema variety, the best fungal partner is C. etunicatum, followed by R. fasciculatus and, finally, Funneliformis mosseae. However, for the plants of the Xewel variety, R. fasciculatus is the most efficient, followed by F. mosseae and C. etunicatum. This suggests that, in tomatoes, the efficiency of mycorrhizal symbiosis under water stress conditions is not only dependent on the host plant but on both associated symbiotic partners. Hence, it is a need for screening to identify the best symbiotic couples in a stressful environment.

摘要： 本发明公开了一种基于Black phosphorus材料的SPPs效应纳米谐振腔及其制作方法，解决长期存在于光学吸收与吸收层厚度之间的矛盾关系。包括反射层、空间损耗层、吸收层和纳米多孔层。反射层采用金属Al材料；空间损耗层采用Al2O3材料；吸收层采用二维材料黑磷；纳米多孔层采用金属Ag材料；纳米多孔层、吸收层、空间损耗层、反射层依次由上而下竖直分布。本发明通过黑磷材料的应用，增强了光学吸收，同时纳米多孔层的引入，在Ag/Black phosphorus界面处形成明显的SPPs效应，进一步提高吸收增益，拓展了吸收光谱，提升了光伏器件的整体性能，进而推动超薄能量捕获和转换应用的发展。