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Astragalus variabilis Bunge is a widespread locoweed that threatens livestock production in desert grassland. No research has reported its possible ecological functions due to focus being on its negative effect on livestock production. This study aimed to assess the effects of A. variabilis on soil properties and its possible role in improving soil quality in desert grassland. Soil samples were collected in Astragalus patches and the adjacent bare patches over two successive growing seasons in Alxa desert grassland where A. variabilis was favoured to spread. Soil properties including texture, water content, dry bulk density, porosity, available nutrients, organic matter, and soil microbial biomass were determined at 15 study sites. There was no significant difference in soil texture between Astragalus-dominant and bare patches; but organic matter (OM), available N and P, and microbial biomass in surface soil (0–30 cm) were significantly higher in Astragalus patches. Furthermore, microbial biomass showed a significantly positive correlation with available nutrients and OM. Levels of water soluble salt were significantly lower in A. variabilis surface soils under drought conditions. Results suggested that A. variabilis was associated with some positive changes in soil properties, and was potentially important in improving soil chemical and microbial properties in desert grassland ecosystems. Consequently, total elimination of locoweed should not necessarily be considered the best solution to locoweed poisoning in livestock.

Non-native invasive plant species influence plant community composition and competitively eradicate native species. However, there is doubt regarding how global invasive species increase and explosively interfere with native plants. Invasive plants always have strong allelopathic potential. In this study, allelopathic effects of switchgrass on redroot pigweed and crabgrass growth were investigated by field and laboratory experiments. Within a 0.4-m distance of switchgrass, density and shoot biomass of native species were significantly suppressed in the field, with 95.1% and 93.0% inhibition on density of redroot pigweed and crabgrass and with 99.0% and 97.7% inhibition on shoot biomass, respectively, during the third growing season. Significant inhibitory effects on shoot and root biomass were observed at the 5:5 (switchgrass–native species) proportion in glass bottles, by 41.57% and 51.21% for shoot and root biomass of redroot pigweed and by 33.42% and 56.95% for shoot and root biomass of crabgrass, respectively. Results of a glass bottle experiment showed that shoot and root biomass of redroot pigweed and crabgrass could be significantly inhibited by contact with switchgrass root. Results of a Petri dish experiment showed that aqueous extracts of switchgrass significantly inhibited germination process of both species at high concentrations, with 90.74% and 18.62% inhibition on germination rate and plumule length of redroot pigweed and with 63.59%, 16.38%, and 19.92% inhibition on germination rate, plumule, and radicle lengths of crabgrass, respectively, at the concentration of 0.1 g·mL−1. This report demonstrated that switchgrass had allelopathic effects on redroot pigweed and crabgrass growth.

Pennisetum × advena (purple fountain grass) is an ornamental grass with considerable commercial value. In vitro induction of hexaploids and evaluation of the morphological and anatomical traits in P. × advena were conducted in this study. Nine independent hexaploids were generated from calli, which was initiated from immature inflorescence tissue of triploid P. × advena, treated with 0.1% colchicine for 24 h. Their ploidy levels were first screened by flow cytometry and further identified by chromosome counting. Compared with the triploids, the hexaploids showed a significant delay in flowering, and reduction in plant height, the number of tillers and number of inflorescences per plant, leaf length and width, inflorescence diameter, and the number of florets per inflorescence, but an increase in floret fresh weight, and anther diameter and length. Pollen grains in the hexaploids were well developed, and their fertility was restored. The production of hexaploids of P. × advena by colchicine treatment, and assessment of their growth parameters and pollen fertility, provide important information for future breeding of P. × advena. Nine independent hexaploids were generated from calli derived from immature inflorescence tissue of triploid Pennisetum × advena by a colchicine treatment, and their morphological and anatomical traits were evaluated.

Precipitation is a primary climatic determinant of grassland productivity, with many global change experiments manipulating precipitation. Here we examine the impacts of precipitation addition and reduction treatment intensity and duration on grassland above- (ANPP) and below- (BNPP) ground net primary productivity in a large-scale meta-analysis. We tested, 1) the double asymmetry model of sensitivity, specifically whether the sensitivity of productivity decreases with treatment intensity under increased precipitation and increases with treatment intensity under decreased precipitation, 2) whether the sensitivity of productivity to precipitation change decreases with treatment length, and 3) how the sensitivity of productivity changes with climate conditions. ANPP showed higher sensitivity than BNPP under increased precipitation but similar sensitivity to BNPP under decreased precipitation. The sensitivity of ANPP and BNPP decreased with increasing treatment intensity (e.g., percentage change in precipitation, ΔPPT) and leveled off in the long-term. With increased precipitation, the sensitivity of productivity decreased with increasing treatment length (e.g., experimental duration) and leveled off in the long-term, whereas the sensitivity increased with increasing treatment length under reduced precipitation. Furthermore, the sensitivity of productivity to precipitation change decreased with increasing mean annual precipitation and temperature. Finally, our meta-analysis shows that above- and belowground net primary productivity have asymmetric responses to precipitation change. Together these results highlight the complex mechanisms underlying the impacts of precipitation change, particularly the intensity and duration of such changes, on grassland productivity.

Salix matsudana is an important tree species for shelterbelt and barren hill afforestation in North China. Knowledge of the seasonal pattern of the stem radial growth (SRG) of S. matsudana and its response to environmental factors is crucial for understanding the tree growth and climate relationships in the increasingly warm and dry climate of North China. To this end, a field trial was conducted in a semi-arid area of North China, and the stem radial dynamics of eight sample trees at two sites (four trees per site) with different soil moisture regimes, as well as the meteorological and edaphic conditions, were monitored from May to October in 2016 and 2019. During the growing season, the daily mean air temperature was 1.69 °C higher in 2019 than in 2016, and the total precipitation was 179.2 mm lower in 2019 than in 2016. The results showed that the seasonal pattern of S. matsudana SRG was divided into the initial stage (stage 1), the rapid growth stage (stage 2), and ending stage (stage 3) in terms of the threshold of 0.02 mm day−1 (daily growth rate). The initiation of stage 2 in 2019 (day of year (DOY) 126) was 48 days earlier than that in 2016 (DOY 174). However, the date on which the maximum growth rate was reached occurred also 34 days earlier, indicating the co-occurrence of the positive effect of the higher temperature in 2019 than in 2016 on growth initiation in stage 1 as well as the negative consequences of the water deficit on tree growth in stage 2. Higher cumulative growth of S. matsudana at the high soil moisture site was monitored relative to the low soil moisture site throughout the trial, which could be attributed to differences in soil moisture and the initial stem size of the trees in 2016 and 2019, respectively. Temperature and soil moisture were the main factors restricting daily SRG, but the growth of S. matsudana subjected to prolonged summer water stress would be less significantly limited by soil moisture in stage 3. These results showed that the seasonal pattern of SRG of S. matsudana was closely related to the dynamics of the soil and climatic factors. Therefore, seasonal variation in growth-limiting factors should be considered when forecasting tree growth in response to climate change in North China.

A kind of silicone rubber (SR)/paraffin (Pa)@silicon dioxide (SiO2) composite form-stable phase change material (PCM) was developed in this paper. Pa@SiO2 was obtained by choosing Pa as PCM core microencapsulated in SiO2 shell based on tetraethoxysilane (TEOS) and γ-aminopropyl triethoxysilane (APTES) as precursors, then Pa@SiO2 microencapsules were embedded in SR matrix to fabricate SR/Pa@SiO2 composites. The SiO2 shell can provide a barrier for the melted Pa and meanwhile have reinforcing effect on SR as inorganic filler. The in-situ modification of SiO2 shell using APTES owing to the amino groups can not only prevent agglomeration, but also increase interfacial bonding between Pa@SiO2 with SR. The thermal and mechanical properties of the form-stable PCMs were characterized by differential scanning calorimetry (DSC) and mechanical tests. The results showed that the thermal and mechanical properties of SR/Pa@SiO2 composites were better than those of SR/Pa and SR/Pa/SiO2. Leakage test was conducted by heating the prepared composites over the melting temperature of Pa. The SR/Pa@SiO2 composites were found as form-stable PCM with low leakage rate. The phase change latent heat of the SR/Pa@SiO2 composites was up to 92.39 J g−1 and the composites can be used for thermal energy storage.

A series of paraffin/expanded graphite (EG) composites with various mass fraction were prepared. The microscopic geometry configuration, thermal conductivity and saturation sorption capacity of EG were obtained. In this paper, a method based on the experiments of EG pores was proposed for constructing geometric models. The geometric model constructed by this method has obvious anisotropy and has been employed in the calculation. Furthermore, the numerical results of thermal conductivity indicate anisotropy of a single-pore. Moreover, it had been observed by experiment that the anisotropy is weakened and transformed to isotropy in the process of combining geometric models with a large number of single pores. The final numerical results agree well with the experiments, which validates the precision and reliability of the proposed model. The increasement of thermal conductivity is also calculated and discussed during the phase change process of paraffin/EG.

A novel kind of paraffin-based shape-stable phase change materials (SSPCMs) was prepared by introducing paraffin into reduced graphene oxide (rGO)/carbon nanotubes (CNTs) aerogel via vacuum-assiste...

Boron carbide (B4C) is an important type of neutron radiation shielding material with relatively high efficiency due to the high content of 10B element. Incorporation of B4C particles into polymer to prepare high-performance neutron radiation shielding material has become more and more important for the safe operation of nuclear power in the defense industry and nuclear power plant. The polyimide/B4C composite films with different micro-sized B4C contents were successfully prepared by in-situ polymerization. Silane coupling agent KH550 was employed to functionalize B4C particles to improve the dispersion of B4C particles in the polyimide matrix with strengthened interfacial interaction. As shown that the micro-sized B4C functional particles can be well dispersed in the BPDA/ODA polyimide matrix. With the B4C content increase, thermal stability of the polyimide/B4C composite films can be significantly improved, even mechanical properties partly declined. Meanwhile, the polyimide/B4C composite films exhibit good thermal neutron radiation shielding properties. The neutron permeability I/I0 changes exponentially with the change of B4C content. When the B4C content is increased to 30 wt%, the polyimide/B4C composite films show optimum properties combination with thermal decomposition temperature (Td10) of 622 °C, neutron permeability (I/I0) of 0.24 (800 μm in thickness), and tensile strength of 406 MPa. The composite thus shows great potential for use in applications which require materials with high thermal stability and neutron radiation shielding ability, such as fusion reactor system and nuclear waste disposal.

Background Carex L. is one of the largest genera in the Cyperaceae family and an important vascular plant in the ecosystem. However, the genetic background of Carex is complex and the classification is not clear. In order to investigate the gene function annotation of Carex, RNA-sequencing analysis was performed. Simple sequence repeats (SSRs) were generated based on the Illumina data and then were utilized to investigate the genetic characteristics of the 79 Carex germplasms. Results In this study, 36,403 unigenes with a total length of 41,724,615 bp were obtained and annotated based on GO, KOG, KEGG, NR databases. The results provide a theoretical basis for gene function exploration. Out of 8776 SSRs, 96 pairs of primers were randomly selected. One hundred eighty polymorphic bands were amplified with a polymorphism rate of 100% based on 42 pairs of primers with higher polymorphism levels. The average band number was 4.3 per primer, the average distance value was 0.548, and the polymorphic information content was ranged from 0.133 to 0.494. The number of observed alleles (Na), effective alleles (Ne), Nei’s (1973) gene diversity (H), and the Shannon information index (I) were 2.000, 1.376, 0.243, and 0.391, respectively. NJ clustering divided into three groups and the accessions from New Zealand showed a similar genetic attribute and clustered into one group. UPGMA and PCoA analysis also revealed the same result. The analysis of molecular variance (AMOVA) revealed a superior genetic diversity within accessions than between accessions based on geographic origin cluster and NJ cluster. What’s more, the fingerprints of 79 Carex species are established in this study. Different combinations of primer pairs can be used to identify multiple Carex at one time, which overcomes the difficulties of traditional identification methods. Conclusions The transcriptomic analysis shed new light on the function categories from the annotated genes and will facilitate future gene functional studies. The genetic characteristics analysis indicated that gene flow was extensive among 79 Carex species. These markers can be used to investigate the evolutionary history of Carex and related species, as well as to serve as a guide in future breeding projects.

Globally, soils store two to three times as much carbon as currently resides in the atmosphere, and it is critical to understand how soil greenhouse gas (GHG) emissions and uptake will respond to ongoing climate change. In particular, the soil‐to‐atmosphere CO2 flux, commonly though imprecisely termed soil respiration (R S), is one of the largest carbon fluxes in the Earth system. An increasing number of high‐frequency R S measurements (typically, from an automated system with hourly sampling) have been made over the last two decades; an increasing number of methane measurements are being made with such systems as well. Such high frequency data are an invaluable resource for understanding GHG fluxes, but lack a central database or repository. Here we describe the lightweight, open‐source COSORE (COntinuous SOil REspiration) database and software, that focuses on automated, continuous and long‐term GHG flux datasets, and is intended to serve as a community resource for earth sciences, climate change syntheses and model evaluation. Contributed datasets are mapped to a single, consistent standard, with metadata on contributors, geographic location, measurement conditions and ancillary data. The design emphasizes the importance of reproducibility, scientific transparency and open access to data. While being oriented towards continuously measured R S, the database design accommodates other soil‐atmosphere measurements (e.g. ecosystem respiration, chamber‐measured net ecosystem exchange, methane fluxes) as well as experimental treatments (heterotrophic only, etc.). We give brief examples of the types of analyses possible using this new community resource and describe its accompanying R software package., Here we describe the lightweight, open source COSORE (COntinuous SOil REspiration) database and software. COSORE focuses on automated, continuous and long‐term greenhouse gas flux datasets, and is intended to serve as a community resource for earth sciences, climate change syntheses and model evaluation.

Graphene encapsulating paraffin (paraffin@graphene) microcapsules were fabricated by electrostatic interaction-based self-assembly. An aqueous dispersion of graphene sheets charged with cation, wer...

In the research of wide-range light-absorbing coordination polymers, to enhance intermolecular or intramolecular charge transfer (CT) and decrease the electron transition excitation energy, a dedicatedly designed novel pyridine diketopyrrolopyrrole (DPP) ligand with strong electron-withdrawing unit were introduced into the Zn, Cu and 1,4-benzenedicarboxylic acid (BDC) based coordination frameworks and porous coordination polymers DPP-Zn(BDC) and DPP-Cu(BDC) were obtained, respectively. By comparing study with physically-mixed samples DPP + Zn(BDC) and DPP + Cu(BDC), a fresh light-absorbing peak around 720 nm is observed and makes the samples exhibit a wide-range absorption in the range of 200–1400 nm and gives another experimental evidence for the research of charge transfer effect in naphthalenediimide-based metal-organic framework Zn2(NDC)2(DPNI) (J. Phys. Chem. Lett. 2013, 4, 453–458). The tremendous red-shift of absorbing onset wavelength could be ascribed to the enhanced intermolecular or intramolecular CT due to electron-withdrawing DPP ligands. At the mean time slow-photon effect is also discussed. The materials have been also characterized through powder XRD, FT-IR, SEM, XPS, solution-state spectra techniques and etc. This study underscores the importance of analyzing the extended structure for interpreting photophysical data based on the potential factors: CT, slow photon, or J-coupling. Moreover the research work might inspire the construction of light-responsive coordination polymers or metal-organic frameworks (MOFs) for charge or electron transfer.

The selection of plants on green roofs should be tailored to the local climate. However, little is known about the long-term performance of plants in a Dwa climate (in the Koppen climate classification). This study follows the performance of 10 Crassulacean species (four species of Phedimus and six of Sedum) grown at four substrate depths (5, 10, 15, and 20 cm) over eight years on an unirrigated roof in Beijing, China. We found that the climate in Beijing, particularly the specific distribution of precipitation, had a substantial influence on plant growth and the community dynamics on extensive green roofs, and the dry and cold winters were the main factors that affected the plant survival on unirrigated green roofs. In such a climate, species with rootstocks or thickened fibrous roots performed better than species with entirely fibrous roots. Although deeper levels of substrate promoted better plant survival and performance, the species richness at all four depths continued to decrease. By the end of this research, only Phedimus aizoon and Phedimus floriferus ‘Weihenstephaner Gold’ still survived, and Phedimus aizoon was the only species that was alive at all of the four substrate depths. This research emphasized the importance of long-term research. The results of this study also revealed that the substrate moisture content was a more important factor than the substrate depth on the survival of plants over winter. To increase the rate of survival of plants on extensive green roofs over winter in Beijing, we advise the provision of supplementary irrigation before winter in years when the plants have experienced a dry autumn.

In order to improve the anti-corrosive and anti-oxidative properties of electroless Ni-P coating (ENPC), a vanadium conversion coating (VCC) was fabricated on the surface of the ENPC. SEM i...

Novel microencapsulated phase change materials (MEPCMs) with high encapsulation capacity and enhanced leakage-prevention performance were prepared by in situ polymerization. For these MEPCMs, paraffin and melamine-formaldehyde resin (MF) are respectively used as core and shell, and graphene oxide (GO) nanosheets, which can be seen as extra protective screen, are situated at the interface between the core and the shell. Effects of GO on morphology, microstructure and properties of MEPCMs were characterized by scanning electronic microscopy (SEM), laser diffraction particle analyzer, atomic force microscopy (AFM), Fourier transformation infrared spectroscopy (FTIR), X-ray diffractometry (XRD), transmission electron microscopy (TEM), differential scanning calorimetry (DSC), thermogravimetric analysis (TG) and paraffin leakage rate test. The results show that the fabricated MEPCMs with GO nanosheets have gradual increasing average diameters from 6.32 to 15.89 μm with an increase content of GO, while the size of MEPCMs without GO is 5.63 μm. When the time of leakage rate test is 50 h, the MEPCMs prepared with 0.5 mg/mL GO aqueous dispersion have considerably high encapsulation ratio of 93.9 wt.%, and the leakage rate is reduced by 93.1% compared with those without GO. The high encapsulation capacity and enhanced leakage-prevention performance might be highly attractive for the application of MEPCMs.

Switchgrass (Panicum virgatum L.) has been developed into a major herbaceous bioenergy crop for the production of cellulosic biofuels in North America and many counties in European. As cultivar selection has a major impact on the ultimate biomass productivity, we evaluated the adaptability and yield potential of 12 switchgrass cultivars including both upland and lowland ecotypes from 2010 to 2013 in the Beijing region, Northern China. Plant height was measured after anthesis, but phytomer number and tiller density were investigated at harvest. One single autumn harvest was carried out each year and biomass yields were determined. It was found that the lowland cultivars ‘Alamo’, ‘Kanlow’ and ‘NewYork’ produced the most biomass for their better performances in number of phytomers per tiller and mass per phytomer, though upland cultivars had higher tiller density. ‘Cave-in-rock’ and ‘Trailblazer’ had better biomass production among the upland cultivars and they were also recommended for planting together with lowland ones for their excellent cold tolerance in this region.

A field study was conducted to investigate the effects of gap disturbance on the seedling establishment process of two native species. Seeds of Agropyron cristatum and Stipa krylovii were reseeded to artificially created gaps in a degraded steppe in North China. There were seven treatments: shoot gaps and root gaps (10 cm, 20 cm and 40 cm in diameters), no gaps (control). Shoot gaps were formed by removing above ground vegetation and below ground biomass without restricting the re-growth of neighbor roots back into the gap. The root gaps were accomplished by using polyvinyl chloride pipes sunk in the soil of shoot gaps to exclude neighboring roots. Seedling emergence, survival and growth performance after 90 days of growing were recorded for both species. Gap significantly increased soil moisture, especially for root gaps. Emergence increased significantly for both species as gap size increased. Seedling emergence and survivorship of both species were greater in gaps than in controls. However, the gap size showed a significantly negative effect on Agropyron cristatum's survivorship. Growth performance of Agropyron cristatum and Stipa krylovii differ in their response to gap disturbance. Gap had positive effects on seedling growth (including seedling height, dry weight, and numbers of tillers and leaves) of Stipa krylovii, but had negative effects on seedling growth of Agropyron cristatum. The two species have significantly different responses to gap disturbance. All results suggest that Stipa krylovii is a gap-enhanced species, and Agropyron cristatum is not. Predation by insects may be one of the key reasons to explain the stand dominance in this grassland.

A superhydrophobic melamine-formaldehyde (MF) foam was prepared by a simple method, in which the hydrophobic SA@Fe3O4 (SA = stearic acid) micro-nanoparticles were fabricated on the surface of MF foam skeleton by in-situ coprecipitation. The modified MF foam showed outstanding superhydrophobic, oleophilic, and magnetic response due to its low surface energy, high porosity, and magnetic particles.

Microstructural and textural characteristics of Zr702 and Zr-2.5Nb alloys before and after rolling (50% reduction in thickness) were characterized and compared by employing electron channel contrast imaging and electron backscatter diffraction techniques, with underlying reasons for the differences between them explored. Results show that the starting microstructure of the Zr702 is mainly comprised of well-equiaxed α-Zr grains while the Zr-2.5Nb presents a typical dual-phase microstructure featured by bulk α grains enclosed by thin β-Zr films. After the 50% rolling, plastic deformation readily occurs through the active operation of prismatic and pyramidal slip in both the Zr alloys. Most grains are found to be elongated along rolling direction with a few less-deformed grains also present (more evident in the rolled Zr702). The β-Zr preexisting in Zr-2.5Nb alloy is softer than α-Zr and could thus be deformed more easily, allowing fewer plastic strains to be accommodated by the α grains. The starting Zr702 has a typical bimodal basal texture that is essentially unchanged after the 50% rolling. The majority of grains in the starting Zr-2.5Nb show scattered orientations with their c-axes away from normal directions (ND). After the same rolling, however, c-axes of most α-grains in the Zr-2.5Nb alloy are aligned to be close to transverse direction or ~30° from the ND (ring-like distribution), different from that of the Zr702. It is demonstrated that the formation of such textural features is related to the preexisting thin β films in the Zr-2.5Nb alloy, in addition to the slip deformation.

A strategy to combat the adverse effects of urbanization involves the installation of green roofs under different climatic conditions. The design and maintenance of green roof systems need to be tailored to the local climate. However, there is a scarcity of reports on the performance of plants under temperate monsoonal climatic conditions. This study follows the growth pattern of 28 species (18 non-succulent forbs and 10 succulents) grown at three substrate depths (10, 15, and 20 cm) over three years on an unirrigated extensive green roof, located in Beijing, China. The results of this study revealed that sustainable extensive green roof was realizable without irrigation in Beijing. In terms of plant adaptive strategies, the most successful plants in this study were the stress-tolerant species, followed by the ruderal species. While deeper substrate could facilitate the survival and performance of plants, substrate moisture content was more significant for the survival of plants in the dry and cold winter in Beijing. This study recommended the use of a substrate depth, which was at least 15 cm deep for unirrigated green roofs in Beijing.

Pennisetum species are widely used as ornamental grasses and may be a valuable genetic resource for their breeding to broaden its genetic basis. At present, new ornamental Pennisetum cultivars are primarily bred via somaclone, which increases the number of variants. It is difficult to estimate whether the suspected variants are authentic in genetic features by morphological traits because of their many limitations. Moreover, although the phylogenetic classification of the Pennisetum genus has been approved in some morphological and cytological studies, genetic evidence is lacking. In the present study, we developed 15 specific simple sequence repeat (SSR) markers with a large amount of polymorphisms and strong distinguishing abilities for Pennisetum ornamental grasses using magnetic bead enrichment. These markers, together with the other 11 reported polymorphic SSRs, were further used for the identification of a broad collection of 55 Pennisetum samples, including nine original taxa and 46 suspected variants. After comparing the genetic characteristics between each variant and its corresponding original taxon, we verified 20 suspected variants that possess the potential to become new, commercially desirable cultivars. The nine original taxa and the 20 verified variants were identified based on the polymorphisms of six core loci, and unique molecular identities with 15 denary digits for each taxon were further established. The rationality of the traditional phylogenetic classification system of the Pennisetum genus was further verified using 147 polymorphic alleles. The present study promotes the protection, registration, breeding, and international communication of Pennisetum ornamental grasses.

1-ethyl-3-methylimidazolium acetate ([EMIM] AC) pretreatment at moderate temperatures (60 °C and 75 °C) was evaluated for improving hydrolysability of Chinese pennisetum, a leading candidate as an energy crop, for bioethanol production. The pretreatment caused slight carbohydrate and lignin loss but significantly changed the material physicochemical characters, such as crystallinity and surface structure. Both changes exhibited positive effects on improving the enzymatic digestibility of the Chinese pennisetum. It was observed that approximately 90% of the cellulose and 50% of the xylan in the Chinese pennisetum after pretreatment at 75 °C were converted to fermentable monosaccharides by the combined cellulases and endo-xylanase. The results suggested that Chinese pennisetum could be effectively pretreated with ([EMIM] AC) pretreatment at moderate temperatures, and the high hydrolysis yield of fermentable sugars from pretreated Chinese pennisetum could be achieved by the synergistic action of accessory xylanase in enzymatic hydrolysis by cellulases.

A novel composites based on ethylene-propylene-diene monomer (EPDM) rubber for gamma shielding were prepared by using carbon blacks (CB) and ball milled PbWO4 (PWO) powder as fillers. The microstructure of ball milled PWO powder which has a uniform morphology in these composites was characterized by scanning electron microscope (SEM), X-ray diffraction (XRD). The mechanical and shielding tests were performed to determine mechanical and radiation attenuation properties, respectively. The results show these materials exhibit excellent mechanical and radiation-resistance properties.

The effects of aqueous ammonia pretreatment on structural properties and hydrolysabilities of Chinese Pennisetum and Hybrid Pennisetum were investigated. Aqueous ammonia pretreatment increased cellulose crystallinities and hydrolysabilities of Chinese Pennisetum and Hybrid Pennisetum. Compared with Chinese Pennisetum, Hybrid Pennisetum showed better enzymatic digestibility. Xylanase supplementation was more effective than the increase of cellulase loadings in the hydrolysis of aqueous ammonia pretreated Chinese Pennisetum and Hybrid Pennisetum. After supplementation of 2mg of xylanase/g dry matter to 5 FPU of cellulases/g dry matter, the hydrolysis yields of cellulose of aqueous ammonia pretreated Chinese Pennisetum and Hybrid Pennisetum were 92.3-95.4%, and the hydrolysis yields of xylan were 86.9-94.2%. High hydrolysability and low dosage of enzyme loadings together with the advantages of high yield and widely distribution demonstrated the potential of Chinese Pennisetum and Hybrid Pennisetum for the production of platform sugars.

In this work, a series of phthalonitrile/hollow glass microsphere (HGM) composite foams for applications in the high temperature and flame retardant fields were prepared and characterized. First, Blends of bisphthalonitrile (CN) and alicyclic imide compounds synthesized from tetrahydrophthalic anhydride (CC) were prepared and sieved (>100 mesh), based on the Thermal Synergistic Polymerization (TSP) effect between phthalonitrile and the alicyclic imide compounds, namely, the -C≡N of the phthalonitrile compound could be completely and rapidly consumed. Then thermogravimetric analysis and rheological behaviors of different molar ratios of CC/CN blend at different temperatures were investigated. HGM were modified using a silane coupling agent (KH550) to improve the interface interaction between HGM and the resin, thereby improving the properties of composite foam. Finally, a series of composite foams were fabricated and characterized. The performance of the foam prepared by BMC method is much better than that of the foam prepared by “RTM” method. The foam (BMC) shows a density of 0.47 g/cm3 with no obvious volume change and little voids, also exhibits good thermal stability up to 400 °C and low thermal conductivity, and provides UL94 V0-rated flame retardancy with total HR of 21.5 KJ/g.

Growing evidence indicates that some grass species are more tolerant to various abiotic and biotic stresses than many crops. Zinc finger proteins play important roles in plant abiotic and biotic stresses. Although genes coding for these proteins have been cloned and identified in various plants, their function and underlying transcriptional mechanisms in the halophyte Zoysia japonica are barely known. In the present study, ZjZFN1 was isolated from Z. japonica using RACE method. Quantitative real time PCR results revealed that the expression of ZjZFN1 was much higher in leaf than in root and stem tissues, and induced by salt, cold or ABA treatment. The subcellular localization assay demonstrated that ZjZFN1 was localized to the nucleus. Expression of the ZjZFN1 in Arabidopsis thaliana improved seed germination and enhanced plant adaption to salinity stress with improved percentage of green cotyledons and growth status under salinity stress. Physiological and transcriptional analyses suggested that ZjZFN1 might, at least in part, influence reactive oxygen species accumulation and regulate the transcription of salinity responsive genes. Furthermore, RNA-sequencing analysis of ZjZFN1-overexpressing plants revealed that ZjZFN1 may serve as a transcriptional activator in the regulation of stress responsive pathways, including phenylalanine metabolism, α-linolenic acid metabolism and phenylpropanoid biosynthesis pathways. Taken together, these results provide evidence that ZjZFN1 is a potential key player in plants' tolerance to salt stress, and it could be a valuable gene in Z. japonica breeding projects.

Thermal dissipation of excess excitation energy is an important photoprotective mechanism that plants have evolved to cope with surplus illumination. However, light-energy-partitioning dynamics in an exotic sand-dune willow (Salix psammophila) commonly used in restoring and/or stabilizing sand lands in northwestern China is largely unknown. In this study, chlorophyll fluorescence (ChlF) of photosystem II (PSII) was continuously monitored in situ in Salix psammophila to investigate plant acclimation processes driven by excessive solar radiation and extreme air temperatures (Ta). As part of a heat-regulation mechanism, energy partitioning is shown to vary with prevailing environmental conditions. In this investigation, energy absorbed during periods of moderate photosynthetically active radiation (PAR &lt, 1200 &mu, moL&middot, m&minus, 2&middot, s&minus, 1) was largely allocated towards photochemistry (&Phi, PSII) with nominal amounts to thermal dissipation through reversible thermal dissipation (&Phi, NPQr). In extremely high solar radiation (PAR &gt, 1500 &mu, 1) or in a cold temperature (Ta &lt, 0 &deg, C), more energy was dissipated by way of non-regulated thermal energy (&Phi, f,D) and sustained thermal dissipation (&Phi, NPQs), leading to non-reversible photoinhibition or photodamage. This was mainly as a result of the low utilization and high absorption of light energy by PSII under cold conditions and physiologically-induced vulnerability. It was concluded that Salix psammophila had a clear tolerance to high temperatures and moderate solar radiation, but tended to be more vulnerable to high solar radiation and cold temperature. Based on species sensitivity to extreme environmental conditions, practical application and extension of Salix psammophila for land-restoration purposes should be approached cautiously, especially in high-latitude or high-altitude desert ecosystems commonly affected by events of high solar radiation and cold temperature.

To provide more insights into the responses of the soil seed bank and vegetation to human disturbance intensity, we selected four land use types, including: native grassland (no human disturbance), abandoned artificial grassland (light human disturbance), artificial grassland (moderate human disturbance), and farmland (severe human disturbance) in a semi-arid climate of northern China. The species composition and density of the soil seed bank were measured, as well as the species composition and amount of vegetation. The native grassland had a significantly higher soil seed density and species richness than the other land use types. Moreover, the common species both in the soil seed bank and vegetation between the native grassland and other land use types gradually decreased as disturbance intensity increased. The abandoned artificial grassland and artificial grassland still had abundant soil seed banks according to their seed density (≥28.2% of the native grassland) and species richness (≥70.0% of the native grassland) to restore the vegetation. Conversely, it was hard to restore the vegetation on the farmland due to its low soil seed density (10.0% of the native grassland) and species richness (40.0% of the native grassland). In conclusion, human disturbance would generate significant negative effects on the soil seed bank in desertified regions in a semi-arid climate; however, the soil seed bank in land use types with light/moderate disturbance are more adapted to vegetation restoration compared with land use types with severe disturbance in a semi-arid region.

The surface characterization and electrostatic property of Hybrid Pennisetum (HP) after alkaline sulfite pretreatment were explored for enhanced enzymatic hydrolysability. The O/C ratio in HP increased from 0.34 to 0.60, and C1 concentration decreased from 62.5% to 31.6%, indicating that alkaline sulfite pretreatment caused poorer lignin but richer carbohydrate on HP surface. Zeta potential and sulfur element analysis indicated that more enzymes would preferably adsorb on the carbohydrate surface of alkaline sulfite pretreated HP because the lignin was sulfonated, which facilitated the decrease of non-productive adsorption. Glucose yield of alkaline sulfite pretreated HP reached to 100% by synergistic action of cellulase and xylanase in the hydrolysis, which was significantly higher than that of NaOH pretreated, and the concentration of glucose released was 1.52times higher. The results suggested that alkaline sulfite pretreatment had potential for improving the HP hydrolysability, and the surface characterization and electrostatic property facilitated the enzymatic digestibility.

Switchgrass is a photoperiod-sensitive energy grass suitable for growing in the marginal lands of China. We explored the effects of extended photoperiods of low-irradiance light (7 μmol·m-2·s-1, no effective photosynthesis) on the growth, the biomass dry weight, the biomass allocation, and, especially, the stem digestibility and cell wall characteristics of switchgrass. Two extended photoperiods (i.e., 18 and 24 h) were applied over Alamo. Extended light exposure (18 and 24 h) resulted in delayed heading and higher dry weights of vegetative organs (by 32.87 and 35.94%, respectively) at the expense of reducing the amount of sexual organs (by 40.05 and 50.87%, respectively). Compared to the control group (i.e., natural photoperiod), the yield of hexoses (% dry matter) in the stems after a direct enzymatic hydrolysis (DEH) treatment significantly increased (by 44.02 and 46.10%) for those groups irradiated during 18 and 24 h, respectively. Moreover, the yield of hexoses obtained via enzymatic hydrolysis increased after both basic (1% NaOH) and acid (1% H2SO4) pretreatments for the groups irradiated during 18 and 24 h. Additionally, low-irradiance light extension (LILE) significantly increased the content of non-structural carbohydrates (NSCs) while notably reducing the lignin content and the syringyl to guaiacyl (S/G) ratio. These structural changes were in part responsible for the observed improved stem digestibility. Remarkably, LILE significantly decreased the cellulose crystallinity index (CrI) of switchgrass by significantly increasing both the arabinose substitution degree in xylan and the content of ammonium oxalate-extractable uronic acids, both favoring cellulose digestibility. Despite this LILE technology is not applied to the cultivation of switchgrass on a large scale yet, we believe that the present work is important in that it reveals important relationships between extended day length irradiations and biomass production and quality. Additionally, this study paves the way for improving biomass production and digestibility via genetic modification of day length sensitive transcription factors or key structural genes in switchgrass leaves.

Biochar produced from rice straw (RC) and maize stalk (MC) was amended to the heavy metal-contaminated soil to investigate the effects of different biochar feedstock and particle size (fine, moderate, coarse) on the accumulation of Cd, Zn, Pb, and As in Brassica chinensis L. (Chinese cabbage). The concentrations of Cd, Zn, and Pb in shoot were decreased by up to 57, 75, and 63%, respectively, after biochar addition (4%). Only MC decreased As concentration in B. chinensis L. shoots by up to 61%. Biochar treatments significantly decreased NH4NO3-extractable concentrations of Cd, Zn, and Pb in soil by 47-62, 33-66, and 38-71%, respectively, yet increased that of As by up to 147%. Amendment of RC was more effective on immobilizing Cd, Zn, and Pb, but mobilizing soil As, than MC. A decrease in biochar particle size greatly contributed to the immobilization of Cd, Zn, and Pb in soil and thereby the reduction of their accumulations in B. chinensis L. shoots, especially RC. Increases in soil pH and extractable P induced by biochar addition contributed to the sequestration of Cd, Zn, and Pb and the mobilization of As. Shoot biomass, root biomass, and root system of B. chinensis L. were enhanced with biochar amendments, especially RC. This study indicates that biochar addition could potentially decrease Cd, Zn, Pb, and As accumulations in B. chinensis L., and simultaneously increase its yield. A decrease in biochar particle size is favorable to improve the immobilization of heavy metals (except As). The reduction in Cd, Zn, Pb, and As levels in B. chinensis L. shoots by biochar amendment could be mainly attributed to a function of heavy metal mobility in soil, plant translocation factor, and root uptake.

Polyploidization is regularly regarded as an important tool for the generation of innovative germplasm resources and plant breeding. In this study, autopolyploid switchgrass lines were produced from calli derived from immature inflorescence of tetraploid switchgrass ( Panicum virgatum L.), both lowland cv. Alamo and Kanlow, and upland cv. Ranlow, through colchicine treatments. Ploidy levels of plantlets regenerated from the calli were screened by flow cytometry. Growth characteristics of the tetraploid and octoploid switchgrass cultivars were further investigated in a field experiment. Compared with the tetraploid plants of the three switchgrass cultivars, the corresponding octoploid plants showed significant reduction in plant height, number of tillers per plant and fresh matter, but an increase in leaf length and width.

Correctly quantifying the relationships between soil respiration and environmental factors and their sources of variability is essential to predict future carbon fluxes and climate feedback. Soil water conditions and soil temperature strongly affect soil respiration and the dynamics of soil organic matter. Despite this, simulation of soil respiration (Rs) based on soil temperature (Ts) and soil volumetric water content (θ) must still be improved, as demonstrated by its discrepant model performance among different seasons. With the objective of gaining a further understanding of the relationships of Rs with Ts and θ and providing an improved model to simulate Rs variations, we measured hourly Rs, Ts and θ using the chamber technique in artificial smooth brome grassland for analysis. We began by dividing the four seasons of a year according to the daily mean air temperature, followed by representing the seasonal variation of Rs, Ts and θ. We found that Rs correlated significantly with Ts in an exponential relationship and with θ in a parabolic relationship seasonally, where the determination coefficient of the Rs-θ relationship was significantly larger than that of the Rs-Ts relationship. We also discovered that the shape of the Rs-θ relationship was seasonally dependent because the optimal θ and the width of the peak Rs around the optimal θ were seasonally specific. Finally, by considering seasonality, the combinational simulation model explained more variation of soil respiration. Thus, seasonality should be considered for more reliable model simulations of soil respiration. These findings are relevant for more accurate predictions and modelling of soil respiration, particularly in temperate artificial grasslands with a continental monsoon climate, where the ‘Birch effect’ strengthens seasonality, and these findings further our understanding of changes in the rates of soil carbon losses as artificial grassland is established.