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The objective of this study is to produce multi-criteria model for the dry weight prediction of Wedelia trilobata under flooding and nitrogen conditions. Plants of W. trilobata were grown in a greenhouse, and treatments were given for two months. Growth parameters of 60 plants were used to build a numerical model. The neural network model was built using Quasi-Newton approaches that containing Broyden-fletcher-goldfarb-shanno gradient (BFGS) learning algorithm, multilayer perceptron (MLP) training algorithm and sigmoid axon transfer function along with 10 neurons at the input network, 9 neurons in the hidden layer, and 1 neuron in the output layer (10-9-1). The selection and validation of the best predictor model were based on lower values of errors and higher value of R². The selected model had a higher values of R² = 0.90 and lower values of errors i.e (relative approximate error, RAE = 0.004, root mean square error, RMS = 0.027, mean absolute error, MAE = 0.004, mean absolute percentage error, MAPE = 0.013). Moreover, the highest rank 1 was obtained for leaf area during sensitivity analysis followed by water potential and photosynthesis ranked 2rd and 3th, respectively. The constructed model of W. trilobata under flooding and nitrogen conditions is the new feature in the management of invasive plant species and gives direction to control its spread. [ABSTRACT FROM AUTHOR]

Anaerobic Fe(II) Oxidizing Denitrifiers (AFODN), a type of newly found Fe(II)-oxidizing bacteria, play an important role in iron and nitrogen cycling. In the present study, a novel AFODN strain PXL1 was isolated from anaerobic activated sludge. Phylogenetic analysis of 16S rRNA gene sequence revealed similarity between this strain andCitrobactor freundii. The strain reduced 30% of nitrate and oxidized 85% of Fe(II) over 72 h with an initial Fe(II) concentration of 3.4 mM and nitrate concentration of 9.5 mM. Oxidation of iron was dependent on the reduction of nitrate to nitrite in the absence of other electron donors or acceptors. Nitrate reduction and Fe(II) oxidation followed first-order reaction kinetics. Iron oxides accumulated in the culture were analyzed by Fourier transform infrared (FTIR) spectroscopy, X-ray diffraction (XRD) spectroscopy and scanning electron microscopy-energy dispersive X-ray spectroscopy (SEM-EDS). The strain recovered deposited oxidized Fe in the form of amorphous Fe oxides. [ABSTRACT FROM AUTHOR]

A field experiment based on a monolith method using flooding irrigation under mulch film (FI) as a control was conducted to investigate soil salinity dynamics under drip irrigation with mulch film (DI) and its effects on cotton root length. The average soil salinity increased with duration of irrigation, but salt distribution in the soil profile was uneven and showed strong accumulation in the soil between adjacent mulch films. With advancing growth of cotton plants, the area of salt accumulation gradually expanded, especially from 110 to 125 days after sowing (DAS), when salinity distinctly increased in the 0- to 40-cm soil depth and at distances 30–70 cm from drip lines; the electrical conductivity (EC) under DI in all soil samples was at least 3 mS cm−1and in some cases exceeded 5 mS cm−1. Root length declined significantly by 18.1% from 110 to 125 DAS under DI. The soil area showing the greatest decline in root length under DI coincided with the main site of salt accumulation. Correlation analysis of soil EC and root length density indicated the root length declined when soil salt content exceeded 2.8 mS cm−1. However, under FI salt accumulation barely exceeded 2.8 mS cm−1and no reduction in root length was observed. The results indicated that the main reason for decreased root length in cotton under DI was localized accumulation of salinity. [ABSTRACT FROM AUTHOR]

This paper introduces the concept, status and problems of China's environmental management system at the rural-urban interface. The problems of environmental management are closely related to rapid urbanisation and the traditional rural-urban dual management system. Integrating rural and urban environmental concerns into environmental policy and management remains a challenge at the rural-urban interface because of the institutional mismatch between urban environmental policies and rural environmental issues. From the current management status, management goals, related laws and major measures the problems in terms of management process are (1) lack of clear identification of environmental issues; (2) lack of clearly defined responsibilities; (3) inappropriate policies and regulation systems; (4) ineffective implementation of environmental policies and regulations; and (5) lack of supervision in environmental management. The existing environmental management pattern leads to a lack of environmental awareness in residents and environmental quality deterioration in the rural-urban interface. This paper suggests a new environmental management pattern constituting government-led environmental management committees and environmental organisations of public participation for the rural-urban interface in China. This pattern is aimed at facilitating reform of the current rural-urban interface environmental management and promoting integrated development in China's urban and rural areas. [ABSTRACT FROM AUTHOR]

The plants in the Gurbantunggut Desert located in Xinjiang, China are drought adapted species and grow in generally nutrient!poor soils. A survey was conducted in the desert to determine the arbuscular mycorrhizal (AM) status associated with the desert plants which belong to 23 species from 11 families of annuals and perennials. Roots from all plants were examined for the presence of internal and external hyphae, vesicles and coils/arbuscules to determine the status and extent of mycorrhizal colonization. Of the plant species surveyed, 14 (61%) were found to form AM associations, 5 (22%) were possible AM colonized species, and 4 were non-mycorrhizal plants. The proportions of annuals and shrubs forming AM were significantly lower than those of perennials and herbs, respectively. Spore density varied from 5 to 21 per 20 g in soil of root zone. 14 AM fungal taxa in 3 genera were isolated and identified, 10 of which belonged to Glomus, 3 to Acaulospora, and 1 to Archaeospora. Glomus was the dominant genus in all genera identified. G. deserticola and G. etunicatum were the most common taxa isolated, with occurrence frequencies of 77.4% and 74.8%, and relative abundances of 14.4% and 15.5%, respectively. [ABSTRACT FROM AUTHOR]

Biochar has shown potential as a sorbent for reducing Cd levels in water. Euhalophytes, which thrive in saline-alkali soils containing high concentrations of metal ions and anions, present an intriguing opportunity for producing biochar with inherent metal adsorption properties. This study focused on biochar derived from the euhalophyte Salicornia europaea and aimed to investigate its Cd adsorption capacity through adsorption kinetics and isotherm experiments. The results demonstrated that S. europaea biochar exhibited a high specific surface area, substantial base cation content, and a low negative surface charge, making it a highly effective adsorbent for Cd. The adsorption data fit well with the Langmuir isotherm model, revealing a maximum adsorption capacity of 108.54 mg g−1 at 25 °C. The adsorption process involved both surface adsorption and intraparticle diffusion. The Cd adsorption mechanism on the biochar encompassed precipitation, ion exchange, functional group complexation, and cation-π interactions. Notably, the precipitation of Cd2+ with CO32− in the biochar played a dominant role, accounting for 73.7% of the overall removal mechanism. These findings underscore the potential of euhalophytes such as S. europaea as a promising solution for remediating Cd contamination in aquatic environments. [ABSTRACT FROM AUTHOR]

Nitrogen accelerates salt accumulation in the root zone of an euhalophyte, which might be beneficial for inhibiting the salt damage and interspecific competition for nutrients of non-halophytes in intercropping. However, the variations in the effect of euhalophyte/non-halophyte intercropping with nitrogen supply are poorly understood. Here, we selected the euhalophyte Suaeda salsa (suaeda) and non-halophyte Zea mays L. (maize) as the research objects, setting up three cropping patterns in order to explore the influence of nitrogen application on the intercropping effect in the suaeda/maize intercropping. The results showed that the biomass of maize in the intercropping was significantly lower than that in the monoculture, while for suaeda, it was higher in the intercropping than that in the monoculture. The biomass of maize under NO3−-N treatment performed significantly higher than that under no nitrogen treatment. Moreover, under suitable NO3−-N treatment, more salt ions (Na+, K+) gathered around the roots of suaeda, which weakened the salt damage on maize growth. In the intercropping, the effect of NO3−-N on the maize growth was enhanced when compared with the non-significant effect of NH4+-N, but a positive effect of NH4+-N on suaeda growth was found. Therefore, the disadvantage of maize growth in the intercropping suaeda/maize might be caused by interspecific competition to a certain extent, providing an effective means for the improvement of saline–alkali land by phytoremediation. [ABSTRACT FROM AUTHOR]

Background and aims: Plant community stability is threatened by anthropogenic climate changes such as increased precipitation. Arbuscular mycorrhizal (AM) fungi have been shown to drive the resistance of ecosystems against climate changes to provide stable ecosystem functions. However, how AMF affects plant community stability under climate change is still not sufficiently clear in Central Asia. Methods: A comprehensive study was conducted with increased precipitation and suppression of AMF in mycorrhizal and non-mycorrhizal plant communities, respectively. Changes in plant community composition and aboveground biomass were measured, and the temporal stability of plant community was calculated. Results: Mycorrhizal plant community responded more sensitively to the increased precipitation and suppression of AMF than non-mycorrhizal plant community. Species synchrony and population variability were only significantly changed by increased precipitation in the mycorrhizal plant community. The stability of dominant and mycorrhizal plants were positively related to community temporal stability of both plant communities. While contrasted with the positive effects of increased precipitation on community temporal stability, increased precipitation reduced community temporal stability by increasing temporal variations of plant biomass in the mycorrhizal plant community, and by decreasing plant diversity in the non-mycorrhizal plant community. However, AMF buffer the decreases in community stability by increasing plant community biomass under increasing precipitation. Conclusion: Our findings highlight ongoing increases in precipitation potentially weaken the temporal stability of ephemeral plant communities in the desert ecosystem stability; however, AMF can alleviate these negative effects through increasing community biomass, especially in the plant community dominated by mycorrhizal species. [ABSTRACT FROM AUTHOR]

Soil salinization causes the degradation of soil structure, which seriously affects the global agricultural production. Currently, planting halophytes to improve saline soil has been widely used. However, most of the experiments were short-term, and the effect of long-term continuous cropping of halophytes on soil is still uncertain. This study aimed to investigate the multi-year effect of continuous cropping of euhalophyte Suaeda salsa on soil physicochemical properties. The space-for-time substitution approach was used to compare changes in soil physicochemical indicators under 3-year, 5-year, and 7-year continuous cropping periods of Suaeda salsa under drip irrigation, with bareland(0-year) serving as the control. In the 0–20 cm soil layer, the soil moisture content increased from 10.76% to 11.72–14.92%; in the 0–40 cm soil layer, the average bulk density decreased from 1.61 g cm−3 to 1.45–1.46 g cm−3 (P < 0.05), the average total porosity increased from 40.54% to 45.63–46.82% (P < 0.05), the average content of soil water-stable macroaggregates rose from 2.38% to 3.07–7.42%, and the average clay particle content declined from 20.88% to 16.63–18.63%; in the 0–60 cm soil layer, the average total salt content decreased from 48.11 g kg−1 to 12.43–22.01 g kg−1, and the average soil organic matter(SOM) content decreased from 8.73 g kg−1 to 7.40–8.15 g kg−1; in the 0–100 cm soil layer, the average pH value increased from 7.33 to 7.38–7.75, and the average content of Ca2+, Mg2+, Na+, K+, SO 4 2-, and Cl- all decreased, whereas the average HCO 3 - content increased from 0.16 g kg−1 to 0.25–0.29 g kg−1. After 7 years of continuous cropping, the mean weight diameter (MWD) of 0–40 cm soil layer increased by 19.01%, the sodium adsorption ratio (SAR) of 0–40 cm soil layer decreased by 53.57% (P < 0.05), and the soil hydro-chemical type of 0–100 cm soil layer changed from Cl--Na+·Ca2+ to Cl-·SO 4 2--Na+·Ca2+. The salt accumulation in the aboveground part of Suaeda salsa accounted for only 1.85–4.36% of the annual desalination quantity in the 0–100 cm soil layer. The continuous cropping of Suaeda salsa improved the soil structure and promoted salt leaching, which was the main mechanism of soil salt reduction. The results showed continuous cropping of Suaeda salsa under drip irrigation in arid regions is an effective method to improve saline soil, providing a theoretical reference for long-term continuous cropping of halophytes to improve saline soil in arid regions. • Effects of different planting years of Suaeda salsa on soil quality under drip irrigation were investigated. • Continuous cropping of Suaeda salsa can significantly improve soil structure. • Continuous cropping of Suaeda salsa can sustainedly reduce the average salt content of 0–100 cm soil profile. • Mechanism of saline soil improvement by halophytes under drip irrigation was analyzed. • Continuous cropping of Suaeda salsa will cause SOM reduction and soil alkalization in the early stage. [ABSTRACT FROM AUTHOR]

Abstract: 3D Bi2O3 hierarchical architectures were successfully fabricated from electrodeposited bismuth (Bi) film by controlling the ramp rate and reaction temperature of thermal oxidation process. Surface morphology observations show that the 3D Bi2O3 hierarchical architectures exhibit flower-like architectures assembled by dozens of 2D nanoplates with a thickness of 25nm. Characterizations of crystal structure reveal that the 2D nanoplates are well-crystallized β-Bi2O3. Furthermore, the 3D Bi2O3 hierarchical architectures exhibit a strong and wide photoluminescence (PL) signal in the range from 500 to 900nm, with a maximum peak at 759nm. Such unique architectures are expected to be utilized as next generation of nano-scale devices, such as sensors, optics and electronics. [Copyright &y& Elsevier]

Background The caper bush Capparis spinosa L. one of the most economically important species of Capparaceae, is a xerophytic shrub that is well adapted to drought and harsh environments. However, genetic studies on this species are limited because of the lack of its reference genome. Findings We sequenced and assembled the Capparis spinosa var. herbacea (Willd.) genome using data obtained from the combination of PacBio circular consensus sequencing and high-throughput chromosome conformation capture. The final genome assembly was approximately 274.53 Mb (contig N50 length of 9.36 Mb, scaffold N50 of 15.15 Mb), 99.23% of which was assigned to 21 chromosomes. In the whole-genome sequence, tandem repeats accounted for 19.28%, and transposable element sequences accounted for 43.98%. The proportion of tandem repeats in the C. spinosa var. herbacea genome was much higher than the average of 8.55% in plant genomes. A total of 21,577 protein-coding genes were predicted, with 98.82% being functionally annotated. The result of species divergence times showed that C. spinosa var. herbacea and Tarenaya hassleriana separated from a common ancestor 43.31 million years ago. Conclusions This study reported a high-quality reference genome assembly and genome features for the Capparaceae family. The assembled C. spinosa var. herbacea genome might provide a system for studying the diversity, speciation, and evolution of this family and serve as an important resource for understanding the mechanism of drought and high-temperature resistance. [ABSTRACT FROM AUTHOR]

Presents information on a study which evaluated the biological mechanism of controlling cotton aphid or Homoptera: aphididae by the marginal alfalfa zone surrounding cotton field. Methodology of the study; Results and discussion on the study.

Global climate change is one of the most pressing conservation challenges; in particular, changes in precipitation regimes have already substantially influenced terrestrial ecosystems. However, the mechanisms influencing precipitation changes on individual plants and the plant communities in desert grasslands have yet to be fully elucidated. We therefore examine the influence of increased precipitation on plant community compositions in the Gurbantunggut Desert, Xinjiang, northwestern China, from 2005 to 2009. We found that growth of all plant species and the community productivities increased markedly with enhanced water input. Cover of ephemeral synusia also significantly increased due to increased precipitation, implying that the role of the ephemeral community for stabilization of sand dunes was strengthened by increased precipitation. The response of plant community compositions to increased precipitation was primarily reflected as changes in plant density, while increased precipitation did not affect plant species richness and the diversity index. Dominant species drove the response of plant density to increasing precipitation during the five‐year study period. However, the relative responses of rare species were stronger than those of the dominant species, thereby potentially driving species turnover with long‐term increased precipitation. This finding improved our understanding of how increased precipitation drives the changes in plant community composition in desert grasslands and will help to better predict changes in the community composition of ephemerals under future global climate change scenarios. [ABSTRACT FROM AUTHOR]

Maternal effects on offspring seeds are mainly caused by seed position on, and the abiotic environment of, the mother plant. Seed heteromorphism, a special form of position effect, is the production by an individual plant of morphologically distinct seed types, usually with different ecological behaviours. Seed heteromorphism is assumed to be a form of bet hedging and provides an ideal biological model to test theoretical predictions. Most studies of maternal effects on seeds have focused on abiotic environmental factors and changes in mean seed traits of offspring. Suaeda salsa is an annual halophyte that produces dimorphic seeds within the same inflorescence. We tested the hypothesis that plants grown from brown seeds of S. salsa have a higher offspring brown seed:black seed morph ratio and variance in seed size than plants from black seeds. Results from a pot experiment showed that plants grown from brown seeds had a higher brown seed:black seed ratio than plants grown from black seeds. This is the first layer of dynamic bet hedging. Brown seeds had higher size variation than black seeds, and seeds produced by plants from brown seeds also had higher seed size variation than plants grown from black seeds. This is the second layer of dynamic bet hedging. Thus, the maternal effect of seed heteromorphism is dual dynamic bet hedging. Furthermore, for seed traits we verified for the first time the theoretical prediction that an increase in offspring size variability induces an increase in the mean size of offspring. [ABSTRACT FROM AUTHOR]

Abstract To find the hyphal growth of cotton plants and its response to phosphorus (P) application under field conditions, a rhizobox method was used in a field experiment with different P fertilizer levels to collect the soil samples at different distances from the cotton root surface, and measured hyphal density, pH value and soil available P content distribution. We found that the hyphal growth range of cotton can extend to 30 mm from the root surface (under zero P addition), meaning that the cotton root increased its P absorption range by 15-fold under the hyphal growth. Within this range, the hyphal density was controlled by soil P content change. On the one hand, the hyphal extent decreased gradually away from the cotton roots with the increase of the soil available P content. On the other hand, a negative correlation was observed between the hyphal density and the soil available P content in different soil locations of distance away from the cotton root surface. We conclude that under a certain soil available P, the promotion or inhibition for hyphal growth was driven by soil available P change. Highlights • The maximum capacity of mycorrhizal hyphae for P uptake was distances of 3 cm from the cotton root in field conditions. • The root process showed a gradual decreasing influence on hyphal growth with the increase of distance from root surface. • The promotion or inhibition for hyphal growth was driven by soil available P change, caused by the cotton P absorption. [ABSTRACT FROM AUTHOR]

Abstract Apocynum venetum is a promising species to remediate an emerging environmental contaminant lithium (Li). However, no research has been conducted so far relating Li tolerance mechanism. In order to improve the understanding of Li transportation and detoxification, subcellular accumulation and distribution of different chemical forms of Li was studied in Apocynum venetum. Subcellular Li compartmentalization analysis showed that majority of Li was located in vacuole (45.52–72.65%) and cell wall (14.84–29.02%) under Li treatment. Furthermore, water soluble and ethonal extracted Li (inorganic Li) are the main chemical forms of Li taken up by A. venetum. With the increase of Li concentration in the medium, Li content in all subcellular fractions and proportion of F-ethanol form with high mobility increased. The greatest amount of Li was found in soluble fraction in leaves at 25 mg L−1 Li treatment, followed by soluble fraction in leaves at 2.5 mg L−1. These results suggest that Li compartmentation in leaf vacuoles is important in Li detoxification and Li accumulation of A. venetum. Highlights • Little information is available for Li tolerance of Li-accumulator plants. • First document of subcellular distribution and chemical forms of Li. • Li compartmentation in leaf vacuoles are important for Li detoxification. • The amount of Li extracted by 80% ethanol was major chemical form. [ABSTRACT FROM AUTHOR]

Castor bean ( Ricinus communi s) is one of the most important candidate crops that can be used to increase the land cover and crop yield in the arid and saline region of China. To evaluate the effects of arbuscular mycorrhizal (AM) fungi on the growth of castor bean under drought and salt stresses, a pot experiment was carried out to examine how AM fungi improve the plant growth of castor bean by affecting the leaf gas exchange, pigments, and metabolites accumulation of castor bean seedlings. The results showed that AM fungi stimulated plant growth and increased the castor bean aboveground biomass. AM fungi significantly increased the net photosynthetic rate ( A ), stomatal conductance ( g s ) and transpiration rate ( E ) of castor bean and decreased the intercellular CO 2 concentration ( Ci ) under drought and salt stress. The contents of chlorophyll a , chlorophyll b , chlorophyll a  +  b and carotenoids in leaves treated by AM fungi were higher than in those without the AM fungi treatment. AM fungi notably increased the soluble protein and proline contents and decreased the malondialdehyde (MDA) content of castor bean. The results indicated that AM fungi could protect castor bean against drought and salt stresses by improving its leaf gas exchanges and photosynthetic capacity and altering its concentrations of metabolites. Our results highlight that AM fungi might be a promising bio-approach that can be used to plant castor beans in northeast and northwest China. [ABSTRACT FROM AUTHOR]

Although the root/mycorrhizal processes determine phosphorus (P) uptake by crops and P fertilizer use efficiency, knowledge of the plasticity of cotton root/mycorrhizal processes in response to changes in soil P content is lacking. A field experiment was conducted in 2015 and 2016 to investigate the effects of P fertilizer treatments (0, 75, 150, and 300 kg P 2 O 5 ha −1 ) on root/mycorrhizal processes and P uptake by cotton plants. The main aim was to explore the possibility of achieving high P fertilizer use efficiency and high yield simultaneously by optimization of P fertilizer application. A low P application rate (75 kg P 2 O 5 ha −1 ) not only increased root length and hyphal density simultaneously, but also enhanced the spatial distribution of cotton roots in the soil, thereby also increasing the apparent phosphorus recovery (APR). However, P uptake and cotton yield were highest under treatment with 150 kg P 2 O 5 ha −1 . Thus, it is difficult to maximize APR and cotton yield simultaneously. If the production target is to obtain a relatively high yield (80–90% of the highest potential yield), then root/mycorrhizal efficiency in P acquisition can be maximized through optimization of the soil available P content. The optimum soil available P content observed in this study was 15–20 mg kg −1 . [ABSTRACT FROM AUTHOR]

Background and aims: The encroachment of halophytic shrubs including tamarisk into saline meadows is accelerating with global warming in the northern Tarim Basin, Xinjiang, China. However, the role of tamarisk in the spatial heterogeneity of soil resources in different desertification stages remains unclear. Methods: The influences of tamarisk on soil resources were assessed via soil salinity and soil organic matter (SOM) measurements under tamarisk canopies and in interspaces. Geostatistical methods were applied to compare the spatial heterogeneity of these soil properties in three regions representing different desertification stages: 1) a meadow with shrubs, 2) a shrubland and 3) shrub duneland. Results: The highest coefficient of variation (CVs) of the soil analytes and most developed 'resource islands' were observed in the shrubland. The overall variation of most of the soil variables was lower in the shrub duneland than in the shrubland and similar to that in the meadow with shrubs. The distribution of SOM and most soil salinity ions were moderately spatially dependent in the meadow with shrubs but highly spatially dependent in the shrubland and shrub duneland. The autocorrelation distances of the most of soil salinity ions were approximately 6- to 15- fold and 2- to 4-fold highest than the tamarisk shrub size in the meadow with shrubs and shrubland, respectively. In contrast, the distribution range of total soil salinity (TSS) and soil K, Na and Cl in the shrub duneland were 1/5 ~ 2/3 of the tamarisk size. Conclusions: 1) Compared with the effect of tamarisk on soil resource heterogeneity in the meadow with shrubs, that in the shrubland was enhanced due to the larger shrub size and more open and scattered canopy in the latter.2) Although the largest shrub size were observed in the shrub duneland, the role of tamarisk in redistributing soil resources was overriden by those of physical processes due to the loose canopy. 3) The spatial heterogeneity of soil resources is determined by not only tamarisk but also environmental factors, such as the connectivity of bare areas and topography. [ABSTRACT FROM AUTHOR]

This article has been retracted: please see Elsevier Policy on Article Withdrawal ( http://www.elsevier.com/locate/withdrawalpolicy ). This article has been retracted at the request of Editor-in-Chief Marisol Berti in agreement with Editor-in-Chief Maria Jesus Pascual Villalobos. The article has been retracted due to ‘salami slicing publication’. Part of apparently the same study was submitted 10 days earlier and published in Industrial Crops and Products 95(1) (2017) 156-162. ( http://dx.doi.org/10.1016/j.indcrop.2016.09.049 ). The authors accepted this decision and apologized for the trouble caused. As a consequence, pages 42-45 originally occupied by the retracted article are missing from the printed issue. The publisher apologizes for any inconvenience this may cause. [ABSTRACT FROM AUTHOR]

Optimization of nitrogen fertilizer application is an important means of improving castor ( Ricinus communis L.) yield. The method of nitrogen application with drip irrigation under mulch film (DI) differs from that of standard cultivation practices. A field experiment was conducted in 2013 and 2014 to investigate the effects of different nitrogen treatments (0, 100, 200, 300, and 400 kg N ha −1 ) on castor yield, nitrogen use efficiency, and dynamic changes in the spatial distribution of roots under DI. The main objective was to determine the effectiveness of nitrogen fertilizer application for simultaneous improvement of the nitrogen use efficiency and productivity of castor. Yield showed a distinct increase with elevation in nitrogen application rate. The highest yields of 5939.3 and 5812.1 kg ha −1 were attained under nitrogen application of 300 kg N ha −1 in the 2013 and 2014 cropping seasons, respectively. However, application of 400 kg N ha −1 did not further increase yield. Root length increased gradually with increasing nitrogen application from 0 to 200 kg N ha −1 . Under 200 kg N ha −1 , maximum root length was observed and the root length density in the soil was most widely distributed in the entire soil profile, which may account for the high nitrogen use efficiency observed in this treatment (72.4% and 67.4% in 2013 and 2014, respectively). The difference in yield between the 300 kg N ha −1 and 200 kg N ha −1 treatments was not significant. The results suggest that the optimal nitrogen application for castor under DI is between 200 and 300 kg N ha −1 to improve yield and nitrogen use efficiency simultaneously. [ABSTRACT FROM AUTHOR]

Salinity and nitrogen are two important environmental factors that affect the distribution of halophytes in their natural saline habitats. Seeds of the euhalophyte Suaeda salsa L. were harvested from plants that had been treated with 1 or 500 m m NaCl combined with 0.5 or 5 m m NO3−- N (nitrate) for 115 days in a glasshouse. Germination was evaluated under different concentrations of NaCl and nitrate. Plants exposed to high salinity (500 m m) and low nitrate (0.5 m m) tended to produce heavy seeds. Either high salinity (500 m m) or high nitrate (5 m m) increased the brown/black seed ratio. The concentrations of Na+, K+, and Cl− were higher in brown than in black seeds, and NO3− concentrations were higher in black than in brown seeds, regardless of NaCl and nitrate treatments during plant culture. Regardless of NaCl and nitrate concentrations during germination, seeds from plants grown with 0.5 m m nitrate generally germinated more rapidly than seeds from plants grown with 5 m m nitrate, and the difference was greater for black than for brown seeds. Exogenous nitrate during germination enhanced the germination of brown seeds less than that of black seeds. Producing more brown seeds and heavy black or brown seeds appears to be an adaptation of S. suaeda to saline environments. Producing more black seeds, which tend to remain dormant, should reduce competition for nitrogen and appears to be an adaptation to nitrogen-limited environments. In conclusion, nitrate provided exogenously or by mother plants to black seeds may act as a signal molecule that enhances the germination of black S. suaeda seeds. [ABSTRACT FROM AUTHOR]

Species composition and productivity are influenced by water and N availability in semi-arid grasslands. To assess the effects of increased N deposition and water supply on plant species composition and productivity, two field experiments with four N addition treatments, and three N and water combination treatments were conducted in alpine grassland in the mid Tianshan mountains, northwest China. When considering N addition alone, aboveground biomass (AGB) of forbs (F) responded less to N addition than AGB of grasses (G). G increased as an effect of N combined with water addition but F did not show such an effect, reflecting a stronger response of grasses to the interaction of water availability and N than forbs. Under all treatments, N allocation to the aboveground tissue did not change for either forbs or grasses. N deposition and water addition did not alter species richness in the present study. These results suggest that N addition generally promoted AGB but had little effect on species richness in wet years. Snowfall in winter combined with rainfall in the early growing season likely plays a critical role in regulating plant growth of the subsequent year in the alpine grassland. [ABSTRACT FROM AUTHOR]

• Apocynum is widely distributed and geographically diverse plant species. • Apocynum exhibits several medical and economic benefits. • Salt tolerance in Apocynum is associated with better redox- and osmo-regulation. • Apocynum can be used to remediate saline area due to its better ability to remove salts from soil and sequester in leaves. • Both sexual and asexual propagation methods make Apocynum cultivation a great opportunity for the vegetation restoration on saline soils Apocynum belongs to Apocynaceae family, is known as highly stress tolerant plant genus. Apocynum venetum L. and Apocynum pictum Schrenk, locally known as luobuma in China, are used as traditional medical plants and cash crops, and used for the phytoremediation of degraded saline lands. This review was aimed to critically analyzed the biological uses, salt tolerance mechanisms, and propagation methods of both Apocynum species to highlight the significance of the cultivation of Apocynum as a great opportunity for the vegetation restoration in saline soils in the arid region. In saline area, where arable crop production is nearly impossible due to high salt toxicity in soil, cultivation of Apocynum can reduce the levels of salt in soils and can also provide livelihood in the form of high-quality fibre. Critical literature analysis showed that overall salinity tolerance in Apocynum is associated with the regulation of redox regulation and ionic homeostasis, however their molecular regulation has not been identified yet. Findings such as removal of Na+ from soils and enhanced accumulation of flavonoids and antioxidants in leaves under saline environment, are useful in understanding the complex network of salt tolerance in Apocynum. Moreover, the practical adoption and application of different sexual and asexual propagation methods also play an important role in the successful cultivation of Apocynum in saline soils. To sum up, there are broad prospects for vigorously developing Apocynum industry by utilizing saline-alkali lands and carrying out research on cultivation technology and conservation strategy of Apocynum resources in arid lands. [ABSTRACT FROM AUTHOR]

Arid areas play a significant role in the global nitrogen cycle. Dry and wet deposition of inorganic nitrogen (N) species were monitored at one urban (SDS) and one suburban (TFS) site at Urumqi in a semi-arid region of central Asia. Atmospheric concentrations of NH3, NO2, HNO3, particulate ammonium and nitrate (pNH4+ and pNO3−) concentrations and NH4-N and NO3-N concentrations in precipitation showed large monthly variations and averaged 7.1, 26.6, 2.4, 6.6, 2.7 µg N m−3 and 1.3, 1.0 mg N L−1 at both SDS and TFS. Nitrogen dry deposition fluxes were 40.7 and 36.0 kg N ha−1 yr−1 while wet deposition of N fluxes were 6.0 and 8.8 kg N ha−1 yr−1 at SDS and TFS, respectively. Total N deposition averaged 45.8 kg N ha−1 yr−1at both sites. Our results indicate that N dry deposition has been a major part of total N deposition (83.8% on average) in an arid region of central Asia. Such high N deposition implies heavy environmental pollution and an important nutrient resource in arid regions. [ABSTRACT FROM AUTHOR]

Background: Soil salinity is a major abiotic stress that limits agriculture productivity worldwide. Salicornia europaea is well adapted to extreme saline environments with more than 1,000 mM NaCl in the soil, so it could serve as an important model species for studying halophilic mechanisms in euhalophytes. To obtain insights into the molecular basis of salt tolerance, we present here the first extensive transcriptome analysis of this species using the Illumina HiSeq™ 2000. Principal Findings: A total of 41 and 39 million clean reads from the salt-treated (Se200S) and salt-free (SeCKS) tissues of S. europaea shoots were obtained, and de novo assembly produced 97,865 and 101,751 unigenes, respectively. Upon further assembly with EST data from both Se200S and SeCKS, 109,712 high-quality non-redundant unigenes were generated with a mean unigene size of 639 bp. Additionally, a total of 3,979 differentially expressed genes (DEGs) were detected between the Se200S and SeCKS libraries, with 348 unigenes solely expressed in Se200S and 460 unigenes solely expressed in SeCKS. Furthermore, we identified a large number of genes that are involved in ion homeostasis and osmotic adjustment, including cation transporters and proteins for the synthesis of low-molecular compounds. All unigenes were functionally annotated within the COG, GO and KEGG pathways, and 10 genes were validated by qRT-PCR. Conclusion: Our data contains the extensive sequencing and gene-annotation analysis of S. europaea. This genetic knowledge will be very useful for future studies on the molecular adaptation to abiotic stress in euhalophytes and will facilitate the genetic manipulation of other economically important crops. [ABSTRACT FROM AUTHOR]

A recent study (Wolf et al., 2010) suggests that short-lived pulses of N2O emission during spring thaw dominate the annual N2O budget and that grazing decreases N2O emissions during the spring thaw. To verify this we conducted year-round N2O flux measurements from June 2010 to May 2011 in Tianshan alpine grassland in central Asia. No pulse emissions of N2O were found at grazing management sites and nitrogen addition sites during the spring thaw. The contribution of the spring thaw to the total annual N2O budget was small and accounted for only 6.6% of the annual fluxes, with winter emissions accounting for 16.7% and growing season emissions accounting for 76.7%. The difference in N2O emissions attributable to grazing management was not significant ( P > 0.05). Nitrogen input tended to increase N2O emissions at N addition sites during the grass growing season compared with those at unfertilized sites. N2O fluxes showed a significant correlation with air temperature and also with both soil temperature and soil water content at 10 cm depth. [ABSTRACT FROM AUTHOR]

Abstract: To assess the effects of nitrogen (N) deposition on greenhouse gas (GHG) fluxes in alpine grassland of the Tianshan Mountains in central Asia, CH4, CO2 and N2O fluxes were measured from June 2010 to May 2011. Nitrogen deposition tended to significantly increase CH4 uptake, CO2 and N2O emissions at sites receiving N addition compared with those at site without N addition during the growing season, but no significant differences were found for all sites outside the growing season. Air temperature, soil temperature and water content were the important factors that influence CO2 and N2O emissions at year-round scale, indicating that increased temperature and precipitation in the future will exert greater impacts on CO2 and N2O emissions in the alpine grassland. In addition, plant coverage in July was also positively correlated with CO2 and N2O emissions under elevated N deposition rates. The present study will deepen our understanding of N deposition impacts on GHG balance in the alpine grassland ecosystem, and help us assess the global N effects, parameterize Earth System models and inform decision makers. [Copyright &y& Elsevier]

Phreatic evaporation is a great lose for shallow groundwater in the Taklimakan Desert. Given soil type and groundwater table, the limiting rate of phreatic evaporation is defined as the maximum of water transferred from groundwater to soil surface per unit time, which is a key parameter and control condition for phreatic evaporation model developing. The soil water characteristic curve for the aeolian sandy soil in the Taklimakan Desert was fitted with the least square method based on the formula of soil moisture characteristics curve proposed by Van Genuchten, using observed soil moisture and soil water suction data. The unsaturated hydraulic conductivity was determined by the instantaneous profile method in situ and the calculation formula for unsaturated hydraulic conductivity was established. According to the steady flow theory, the quasi-analytical solution of limiting rate of phreatic evaporation was derived on the basis of generalization of the formula of unsaturated hydraulic conductivity. The results show that the soil moisture characteristics in the Taklimakan Desert can be well described by Van Genuchten's formula, and the limiting rate of phreatic evaporation declines by power function with the descending of groundwater table. [ABSTRACT FROM AUTHOR]

A pot experiment was carried out with the following treatments: non-mycorrhizal control and inoculation by arbuscular mycorrhizal fungi (Glomus mosseae (Nicol. & Gerd.) Gerdemann & Trappe or Sclerocystis sinuosa Gerd. & Bakshi) at four P levels (0, 9.5, 19, and 38 mg P kg[sup -1]). Cotton (Gossypium arboreum L. cv. Xin-lu-zao No.l) was used as the host plant. The [sup 15]N-labeled urea (2.5% abundance) was mixed with soil thoroughly at a rate of 100mg Nkg[sup -1]. Colonization by the two arbuscular mycorrhizal fungi significantly improved the growth of cotton plants at all P levels compared with non-mycorrhizal plants. Nitrogen concentration in shoots was not significantly affected by arbuscular mycorrhizal fungi, while the nitrogen content was significantly higher in mycorrhizal plants than in non-mycorrhizal plants. The [sup 15]N atom % excess in mycorrhizal plant was significant lower than that in non-mycorrhizal plants. Considering the derivation of the nitrogen in the cotton plants, mycorrhizal fungi had no significant influence on uptake of nitrogen derived from fertilizer, but increased nitrogen derived from soil significantly. Colonization by mycorrhizal fungi increased the amount of soil available nitrogen ("A[sub N]" value). The results indicate that arbuscular mycorrhizal fungi may facilitated plant acquisition of nitrogen from sources which are not or less available to non-mycorrhizal plants. [ABSTRACT FROM AUTHOR]

Soil salinization threatens agricultural sustainability, especially for arid and semiarid regions. Planting euhalophytes with drip irrigation is proposed to be a feasible solution for the reclamation of saline soils. Thus, by planting an annual halophyte Suaeda salsa with drip irrigation, we assessed the potential of S. salsa to accumulate high amount of salt from soil and change in soil salinity levels in a three-year field study in arid northwestern China. The aboveground parts of S. salsa contained >20% ash salt on a dry weight basis and Na+ and Cl− were the main components. For each year, salt extraction by the aboveground part of S. salsa was ranged from 3749 to 3911 kg ha−1. Soil salinity dramatically decreased year by year by the cultivation of S. salsa , especially in the topsoil layer (0–40 cm). Our study suggested that consecutive cultivation of S. salsa with drip-irrigation is an efficient method to reclaim saline soil in arid and semiarid regions. [ABSTRACT FROM AUTHOR]

• Bacterial communities were geographically distributed along the longitude gradient. • Salinity affected bacterial diversity but not bacterial abundance. • Salinity was the main environmental driver of bacterial communities. • Salinity levels altered the modularity in the bacterial co-occurrence network. Saline soils suppress plant growth and reduce yield worldwide, thereby pose a serious threat to agriculture. Although microbes drive major biogeochemical cycles and play an integral role in agricultural production, understanding of the microbial distribution patterns in saline agricultural systems remains limited. Here we investigated the co-occurrence and biogeographical patterns of bacterial communities in saline agricultural soils at a regional scale in north-west China. Our results revealed a trend towards increasing bacterial abundance at higher longitudes. By contrast, bacterial diversity exhibited different spatial patterns and declined with increasing salinity. Bacteroidetes , Gammaproteobacteria , Alphaproteobacteria and Gemmatimonadetes were the dominant groups across all soil samples (>5% of all sequences). Additionally, members belonging to Flavobacteriaceae , Cytophagaceae , Halomonadaceae , Acidobacteria and Gemmatimonadetes were identified as indicators across the salinity gradient. Salinity levels also affected the modularity of bacterial co-occurrence networks, with module composition differing between soil salinity levels. Bacteria belonging to Acidobacteria subgroup 4, Acidobacteria subgroup 6, Gemmatimonadetes and Rhodospirillales were statistically identified as the keystone taxa. Geographical distance explained 5.08% of the community variation, whereas soil parameters explained 27.26% variation, with salinity as a major driver explaining 15.18% of the variation. Therefore, bacterial communities were geographically distributed along the longitude gradient, and soil salinity was more important than geographical isolation in shaping soil bacterial communities. Taken together, our results indicate that salinity alters bacterial network modularity and drives spatial distribution in saline agricultural soils. [ABSTRACT FROM AUTHOR]

• Plant and AMF community are correlated in Central Asia, support Habitat Hypothesis. • Stability of plant and AMF community are positively correlated and related to SM. • Plant-AMF symbioses stability sharply decrease, when SM drop down to the threshold. Terrestrial ecosystems are composed of above- and belowground community, which have been researched separately for many years even though the two subsystems clearly interact with each other. And it is still less understood how the above- and belowground ecosystems co-response to the changing precipitation in this changing world. To understand the interdependence and co-responses of plant-arbuscular mycorrhizal (AM) fungi symbioses to this facet of climate change, we examined the plant and AM fungal diversity and abundance along both, a transect from east to west of the desert which exhibits an annual precipitation gradient and a topographical transect of a typical sand dune which exhibits a gradient of soil moisture but equal precipitation, in a temperate desert in Central Asia. The results showed that community structure and biomass of plants and AM fungi along both transects were positively correlated and related to either precipitation or soil moisture, strongly support the Habitat Hypothesis. We found a soil moisture threshold between 0.64% and 0.86%, below which the variability of plant coverage, plant species richness, spore density and Shannon-wiener diversity index of both plant and AM fungal communities increased sharply yielding in an average threshold of 0.73% for the stability of plant-AMF symbioses. Our results highlight that increasing precipitation contributes to above- and belowground, and particularly to the overall AM-symbiotic stability in a desert ecosystem. This emphasizes the susceptibility and the importance plant-AMF symbioses for ecosystem stability to climate changes across different scales. [ABSTRACT FROM AUTHOR]

Background The halophyte Suaeda aralocaspica performs complete C4 photosynthesis within individual cells (SCC4), which is distinct from typical C4 plants, which require the collaboration of 2 types of photosynthetic cells. However, despite SCC4 plants having features that are valuable in engineering higher photosynthetic efficiencies in agriculturally important C3 species such as rice, there are no reported sequenced SCC4 plant genomes, limiting our understanding of the mechanisms involved in, and evolution of, SCC4 photosynthesis. Findings Using Illumina and Pacific Biosciences sequencing platforms, we generated ∼202 Gb of clean genomic DNA sequences having a 433-fold coverage based on the 467 Mb estimated genome size of S. aralocaspica. The final genome assembly was 452 Mb, consisting of 4,033 scaffolds, with a scaffold N50 length of 1.83 Mb. We annotated 29,604 protein-coding genes using Evidence Modeler based on the gene information from ab initio predictions, homology levels with known genes, and RNA sequencing–based transcriptome evidence. We also annotated noncoding genes, including 1,651 long noncoding RNAs, 21 microRNAs, 382 transfer RNAs, 88 small nuclear RNAs, and 325 ribosomal RNAs. A complete (circular with no gaps) chloroplast genome of S. aralocaspica 146,654 bp in length was also assembled. Conclusions We have presented the genome sequence of the SCC4 plant S. aralocaspica. Knowledge of the genome of S. aralocaspica should increase our understanding of the evolution of SCC4 photosynthesis and contribute to the engineering of C4 photosynthesis into economically important C3 crops. [ABSTRACT FROM AUTHOR]

Lithium (Li) could be much safer and successful approach to supply Li via Li-fortified food products. This study is highlighting the potential scope of Li supply via Li-biofortification of Luobuma tea (made from Apocynum venetum leaves), which is a very popular beverage in Asia with several medical properties. We explored the possibility of A. venetum as Li-enriched tea and investigated plant growth, Li accumulation, total flavonoids (TFs), rutin and hyperoside concentrations, and the antioxidant capacity of A. venetum. With the increase of additional Li, Li concentration in roots, stems and leaves increased gradually. Compared with the control treatment, 10–15 mg kg−1 Li addition stimulated the growth of A. venetum and 25 mg kg−1 Li addition significantly increased the Li concentration in leaves by 80 mg kg−1. Li application did not decrease TFs, rutin, hyperoside and antioxidant capacity of this medicinal herb. A daily consumption of 10 g Li-biofortified A. venetum leaves (cultivated with 25 mg kg−1 LiCl) can give 592 μg Li intake and would constitute 59% of the provisional recommended dietary daily intake of Li. Our results showed that Li-biofortified A. venetum leaves can be used as Li-fortified tea to enhance Li supply and to improve human health when it was used as daily drink. [ABSTRACT FROM AUTHOR]

Background: There are two plant phosphorus (P)-uptake pathways, namely the direct P uptake by roots and the indirect P uptake through arbuscular mycorrhizal fungi (AMF). Maximizing the efficiency of root and AMF processes associated with P acquisition by adjusting soil conditions is important for simultaneously ensuring high yields and the efficient use of available P. Results: A root box experiment was conducted in 2015 and 2016. The aim was to investigate the effects of different P and soil water conditions on root/mycorrhizal growth and P uptake by cotton plants. Hyphal growth was induced in well-watered soil, but decreased with increasing P concentrations. Additionally, P fertilizers regulated root length only under well-watered conditions, with the longest roots observed in response to 0.2 g P2O5 kg− 1. In contrast, root elongation was essentially unaffected by P fertilizers under drought conditions. And soil water in general had more significant effects on root and hyphal growth than phosphorus levels. In well-watered soil, the application of P significantly increased the cotton plant P uptake, but there were no differences between the effects of 0.2 and 1 g P2O5 kg− 1. So optimizing phosphorus inputs and soil water can increase cotton growth and phosphorus uptake by maximizing the efficiency of phosphorus acquisition by roots/mycorrhizae. Conclusions: Soil water and P contents of 19–24% and 20–25 mg kg− 1, respectively, simultaneously maximized root/mycorrhizal growth and P uptake by cotton plants. [ABSTRACT FROM AUTHOR]