Effects of N:P ratio of Artemisia ordosica on growth influenced by soil calcium carbonate

Soil calcium carbonate(CaCO_3) has a strong solid phosphorus effect, and high content of CaCO_3 can significantly reduce the effectiveness of soil phosphorus. To reveal the limiting effect of soil CaCO_3 on the growth of plants on sand land and its mechanism of plant physiology, we performed pot experiments with a two-factor randomized block design and a three-factor orthogonal design for different soil CaCO_3 content treatments using Artemisia ordosica seedlings. In the experiments, we surveyed plant height, aboveground biomass, root length and root weight and analyzed N, P concentrations and RNA content of the seedlings, and discussed the relationships between relative growth rate(RGR) of the seedlings and N:P ratio as well as RNA. Results show that, the RGRs of plant height and above-ground biomass of the seedlings decreased significantly with the increase of soil CaCO_3 content, and those for root length and root weight decreased. The RGRs of plant height and above-ground biomass of the seedlings were significantly negatively correlated with leaf N:P ratios, but significantly positively correlated with leaf RNA content and leaf P concentrations. It can be seen that soil CaCO_3 is a stress factor for the growth of A. ordosica seedlings, and the growth response of the seedlings under the influence of soil CaCO_3 is in line with the Growth Rate Hypothesis.

Seasonal dynamics of N:P ratio stoichiometry and Ca fraction for four dominant plants in the Alxa Desert

Desert plants take on unique physiologically adaptive mechanisms in response to an adverse environment. In this study, we determined the concentrations of leaf nitrogen(N), phosphorus(P), and calcium(Ca) fraction for dominant species of Artemisia ordosica, A. frigida, Calligonum mongolicum, and Oxytropis aciphylla in the Alxa Desert and discussed seasonal changes of their leaf N:P ratio and Ca fraction. The results showed that, from May to September, the N:P ratios of A. ordosica and C. mongolicum gradually and significantly increased, while those of A. frigida, and O. aciphylla had an increase trend that was not significant; the physiologically active Ca of A. ordosica and A. frigida increased significantly,while that of C. mongolicum and O. aciphylla decreased significantly. The physiologically inert calcium of C. mongolicum increased extremely significantly, while that of others was not significant. There was a significantly positive correlation between the N:P ratio and physiologically active Ca for A. ordosica, and the N:P ratio was significantly and negatively correlated with physiologically active Ca for O. aciphylla. These findings revealed that the physiological regulation mechanism was different for the plants either in earlier stage or later stage of plant-community succession.

Composition,Property Characterization and Application of Agricultural and Forest Biomass Carbon

We analyzed the compositions and basic properties of agricultural and forest biomass carbon,and used the pot method to study the influence of such element on the remediation of contaminated soils and growth of crops.Results show that agricultural and forest biomass carbon contains various nutrients that are necessary for crop growth,high specific surface area,and pore structure development.Cotton stalk charcoal can reduce bioavailability of Cadmium(Cd) in soil.Under mild Cd pollution,soil treated with cotton stalk charcoal adsorbs Cd at a rapid rate.With increasing extent of Cd pollution,Cd adsorption rate gradually slows down and Cd adsorption amount gradually increases.In soil treated with cotton stalk charcoal,the amount of Cd accumulated in the edible portions and roots of Brassica chinensis significantly decrease.The Cd mass fraction of the edible portions and roots are reduced by 49.43%- 68.29%,64.14%- 77.66% respectively.Appropriately adding carbon cotton stalks increases crop biomass.At a certain range,increasing cotton stalk charcoal also promotes the absorption of major nutrients in Brassica chinensis.

Analysis of the Female Characters in On the Road

On the Road is the masterpiece of Kerouac who is one of the most important writers of“Beat Generation”in America in the mid-20th century.It is acclaimed to be the Bible of“Beat Generation”.The novel narrates the stories of how Dean and his friends——some representative characters of the Beats travelled across continental U.S.several times and searched for new lifestyles and new faith on the road.In this novel,male characters are the main characters and the descriptions of all the female characters account for just one sixth of the whole book.Although the portrayal of the female characters is not profound like that of the male characters,the different personalities Kerouac endued the female characters are also the highlights of the novel.As a novel with strong nature of autobiography,Kerouac put his attitude and emotion into his portrayal.So it also can be a reflection of Kerouac’s female concepts.This paper aims at analyzing the female characters in On the Road by studying the types of the female characters in the novel and summarizing Kerouac’s female concepts reflected from the novel.

Soil and microbial C:N:P stoichiometries play vital roles in regulating P transformation in agricultural ecosystems:A review

Stoichiometry plays a crucial role in biogeochemical cycles and can modulate soil nutrient availability and functions. In agricultural ecosystems,phosphorus(P) fertilizers(organic or chemical) are often applied to achieve high crop yields. However, P is readily fixed by soil particles, leading to low P use efficiency. Therefore, understanding the role of carbon:nitrogen:P stoichiometries of soil and microorganisms in soil P transformation is of great significance for P management in agriculture. This paper provides a comprehensive review of the recent research on stoichiometry effect on soil P transformation in agricultural ecosystems. Soil microorganisms play an important role in the transformation of soil non-labile inorganic P to microbial biomass P by regulating microbial biomass stoichiometry. They also mobilize soil unavailable organic P into available P by changing ecoenzyme stoichiometry. Organic materials, such as manure and straw, play an important role in promoting the transformation of insoluble P into available P as well. Additionally, periphytic biofilms can reduce P loss from rice field ecosystems. Agricultural stoichiometries are different from those of natural ecosystems and thereby should receive more attention due to the influences of anthropogenic factors. Therefore, it is necessary to conduct further stoichiometry research on the soil biochemical mechanisms underlying P transformation in agricultural ecosystems. In conclusion, understanding stoichiometry impact on soil P transformation is crucial for P management in agricultural ecosystems.

Heptamethine cyanines in bioorthogonal chemistry

Due to their excellent fluorescence properties and biological function,cyanine dyes have been widely applied in biological imaging.Heptamethine cyanine(Cy7)dyes,as a type of classic near-infrared(NIR)fluorescent dyes,are considered as one of the effective fluorescent tools in the living organisms due to their good biocompatibility and very low background interference.Bioorthogonal reactions performed in living cells and tissues have developed by leaps and bounds in recent years.The NIR fluorescent labeling technique involving cyanine has attracted widespread attention.This review summarizes their recent application in the field of bioorthogonal imaging,mainly concluding Cy7-type dyes,labeling strategy,bioimaging application,etc.We expect this work can provide some helps for the studies of NIR bioorthogonal reaction in vivo.

Catalytic degradation of benzene over non-thermal plasma coupled Co-Ni binary metal oxide nanosheet catalysts

Non-thermal plasma(NTP)has been demonstrated as one of the promising technologies that can degrade volatile organic compounds(VOCs)under ambient condition.However,one of the key challenges of VOCs degradation in NTP is its relatively low mineralization rate,which needs to be addressed by introducing catalysts.Therefore,the design and optimization of catalysts have become the focus of NTP coupling catalysis research.In thiswork,a series of two-dimensional nanosheet Co-Ni metal oxides were synthesized by microwave method and investigated for the catalytic oxidation of benzene in an NTP-catalysis coupling system.Among them,Co_(2)Ni_(1)O_(x)achieves 60%carbon dioxide(CO_(2))selectivity(SCO_(2))when the benzene removal efficiency(REbenzene)reaches more than 99%,which is a significant enhancement compared with the CO_(2)selectivity obtained without any catalysts(38%)under the same input power.More intriguingly,this SCO_(2)is also significantly higher than that of single metal oxides,NiO or Co_(3)O_(4),which is only around 40%.Such improved performance of this binary metal oxide catalyst is uniquely attributed to the synergistic effects of Co and Ni in Co_(2)Ni_(1)O_(x)catalyst.The introduction of Co_(2)Ni_(1)O_(x)was found to promote the generation of acrolein significantly,one of the key intermediates found in NTP alone system reported previously,suggest the benzene ring open reaction is promoted.Compared with monometallic oxides NiO and Co_(3)O_(4),Co_(2)Ni_(1)O_(x)also shows higher active oxygen proportion,better oxygenmobility,and stronger low-temperature redox capability.The above factors result in the improved catalytic performance of Co_(2)Ni_(1)O_(x)in the NTP coupling removal of benzene.

Microbial community and functional genes in the rhizosphere of alfalfa in crude oil-contaminated soil

A rhizobox system constructed with crude oil- contaminated soil was vegetated with alfalfa （Medicago sativa L.） to evaluate the rhizosphere effects on the soil microbial population and functional structure, and to explore the potential mechanisms by which plants enhance the removal of crude oil in soil. During the 80-day experiment, 31.6% of oil was removed from the adjacent rhizosphere （AR）; this value was 27% and 53% higher than the percentage of oil removed from the far rhizosphere （FR） and from the non-rhizosphere （NR）, respectively. The populations of heterotrophic bacteria and hydrocarbon- degrading bacteria were higher in the AR and FR than in the NR. However, the removal rate of crude oil was positively correlated with the proportion of hydrocarbon- degrading bacteria in the rhizosphere. In total, 796, 731, and 379 functional genes were detected by microarray in the AR, FR, and NR, respectively. Higher proportions of functional genes related to carbon degradation and organic remediation, were found in rhizosphere soil compared with NR soil, suggesting that the rhizosphere selectively increased the abundance of these specific functional genes. The increase in water-holding capacity and decrease in pH as well as salinity of the soil all followed the order of AR 〉 FR 〉 NR. Canonical component analysis showed that salinity was the most important environmental factor influencing the microbial functional structure in the rhizosphere and that salinity was negatively correlated with the abundance of carbon and organic degradation genes.

Antibiotic resistance genes in manure-amended paddy soils across eastern China:Occurrence and influencing factors

Pig manure,rich in antibiotics and metals,is widely applied in paddy fields as a soil conditioner,triggering the proliferation of antibiotic resistance genes(ARGs)in soil.However,comprehensive studies on the effects of manure fertilization on the abundance of ARGs and their influencing factors are still insufficient.Here,pig manure and manure-amended and inorganic-amended soils were collected from 11 rice-cropping regions in eastern China,and the accumulation of antibiotics,metals,and ARGs was assessed simultaneously.The results showed that manure fertilization led to antibiotic residues and increased the metal content(i.e.,Zn,Cu,Ni,and Cr).Tetracycline and sulfonamide resistance genes(tetM,tetO,sul1,and sul2)were also significantly enhanced with manure fertilization.According to variance partitioning analysis,the most important factors that individually influenced ARGs were soil physicochemical properties,accounting for 12%of the variation.Significant correlations between soil nutrients and ARGs indicated that manure application enhanced the growth of resistant microorganisms by supplying more nutrients.Metals and antibiotics contributed 9%and 5%to the variations in ARGs,respectively.Their co-occurrence also increased the enrichment of ARGs,as their interactions accounted for 2%of the variation in ARGs.Interestingly,Cu was significantly related to most ARGs in the soil(r=0.26–0.52,p<0.05).Sulfapyridine was significantly related to sul2,and tetracycline resistance genes were positively related to doxycycline.This study highlighted the risks of antibiotic and ARG accumulation with manure fertilization and shed light on the essential influencing factors of ARGs in paddy soils.

A novel phosphorus oxide quantum dots as an emissive nanomaterial for inorganic ions screening and bioimaging

In this work,a novel blue-green fluorescence phosphorous oxide quantum dots(PO QDs)was synthesized by solvothermal method in N-methyl-2-pyrrolidone(NMP)solution without any protection treatment during synthesis.Upon excitation at 400 nm,PO QDs emitted blue-green fluorescence with quantum yield of 0.28.PO QDs exhibited the high inertness to air or moisture,the excellent water solubility,and stable emission intensity in a wide pH range and in high ionic strength solution.Interestingly,PO QDs could give the positive optical response to iron ions(Fe^(3+))and iodine ion(I^(-)).The photoluminescence(PL)of PO QDs could be directly quenched by Fe^(3+).While I^(-)quenched the PO QDs PL by means of Ag^(+)-mediated PO QDs system via the internal filtration effects(IFE)induced by the formation of AgI.Moreover,the biocompatibility and low toxicity of PO QDs verified in bean sprout and Hela cells indicated the promising application of PO QDs in medicine related fields.Furthermore,PO QDs could also be utilized in luminescent composite film for various application scenarios.

Straw biochar strengthens the life strategies and network of rhizosphere fungi in manure fertilized soils

Soil fungi have many important ecological functions,however,their life strategies and interactions in manure fertilized soils are not well understood.The aim of this study was to investigate the effects of biochar amendment on the fungal life strategies and species interactions in ryegrass(Lolium perenne L.)rhizosphere soil by high-throughput sequencing.Three soil treatments were evaluated:soil and pig manure mixture without planting ryegrass and biochar application(bulk soil),mixture with ryegrass planting(rhizosphere soil(RS)),and addition of 2%(w/w)biochar with ryegrass(RS+biochar).Our results indicated that temporal turnover,defined as the slope of linear regression between community similarity and time,was significantly higher in the biochar amendment(slope=-0.2689,p<0.0001)relative to the rhizosphere soil.Following biochar addition,the percentage of species employing slow acclimation ecological strategies decreased(from 27% to 17%)and the percentage of sensitive species increased(from 40% to 50%)in comparison to the rhizosphere soil.Network analysis indicated that fungal communities in the biochar amendment enhanced positive correlations compared to the rhizosphere soil and bulk soil.Structural equation model indicated that soil pH was the most important factor in altering fungal life strategies and interactions in manure fertilized soils.