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Changes in nitrogen (N) deposition and litter mixtures have been shown to influence ecosystem processes such as litter decomposition. However, the interactive effects of litter mixing and ... N‐deposition on decomposition process in desert regions remain poorly identified. We assessed the simultaneous effects of both N addition and litter mixture on mass loss in a litterbag decomposition experiment using six native plants in single‐species samples with diverse quality and 14‐species combinations in the Gurbantunggut Desert under two N addition treatments (control and N addition). The N addition had no significant effect on decomposition rate of single‐species litter (expect Haloxylon ammodendron), whereas litter mass loss and decomposition rate differed significantly among species, with variations positively correlated with initial phosphorus concentration and negatively correlated with initial lignin concentration. After 18 months, the average mass loss across litter mixtures did not overall differ from those predicted from single species either in control or N addition treatments, that is, mixing of different species had no non‐additive effects on decomposition. The N addition, however, did modify the direction of mixture effects and interacted with incubation time. Added N transformed synergistic effects of litter mixtures to antagonistic effects on mass loss after 1 month of decomposition, while transforming neutral effects of litter mixture to synergistic effects after 6 months of decomposition. Our results demonstrated that initial chemical properties played an important role in litter decomposition, while no effects of litter mixture on decomposition process in this desert region. The N addition altered the litter mixture effects on mass loss with incubation time, implying that increased N deposition in the future may have profound effects on carbon turnover to a greater extent than previously thought in desert ecosystems. This paper demonstrated that the initial chemical properties played an important role in litter decomposition, while no effects of litter mixture on decomposition process in this desert region. The N addition altered the litter mixture effects on mass loss with incubation time, implying that increased N deposition in the future may have profound effects on carbon turnover to a greater extent than previously thought in desert ecosystems. more

Cotton (Gossypium hirsutum L.) is an important fiber cash crop, but its root traits related to phosphorus (P) acquisition, including mycorrhizal root traits, are poorly understood. Eight cotton ... varieties bred in northwestern China that were released between 1950 and 2013 were grown in pots with or without one arbuscular mycorrhizal fungal (AMF) species (Funneliformis mosseae) at three P supply levels (0, 50 and 300 mg P as KH2PO4 kg−1). Eleven root traits were measured and calculated after 7 wk of growth. The more recent accessions had smaller root diameters, acquired less P and produced less biomass, indicating an (inadvertent) varietal selection for thinner roots that provided less cortical space for AMF, which then increased the need for a high P fertilizer level. At the two lower P levels, the mycorrhizal plants acquired more P and produced more biomass than non-mycorrhizal plants (3.2 vs. 0.9 mg P per plant; 1.8 vs. 0.9 g biomass per plant at P0; 14.5 vs. 1.7 mg P per plant; and 4.7 vs. 1.6 g biomass per plant at P50). At the highest P level, the mycorrhizal plants acquired more P than non-mycorrhizal plants (18.8 vs. 13.4 mg per P plant), but there was no difference in biomass (6.2 vs. 6.3 g per plant). At the intermediate P level, root diameter was significantly positively correlated with shoot biomass, P concentration and the P content of mycorrhizal plants. The results of our study support the importance of the outsourcing model of P acquisition in the root economics space framework. Inadvertent varietal selection in the last decades, resulting in thinner roots and a lower benefit from AMF, has led to a lower productivity of cotton varieties at moderate P supply (i.e., when mycorrhizal, the average biomass of older varieties 5.0 g per plant vs. biomass of newer varieties 4.4 g per plant), indicating the need to rethink cotton breeding efforts in order to achieve high yields without very high P input. One feasible way to solve the problem of inadvertent varietal selection for cotton is to be aware of the trade-offs between the root do-it-yourself strategy and the outsourcing towards AMF strategy, and to consider both morphological and mycorrhizal root traits when breeding cotton varieties. more

Abstract Aims Woody plants are widely distributed in various grassland types along the altitudinal/climatic gradients in Xinjiang, China. Considering previously reported change in carbon (C) storage ... following woody plant encroachment in grasslands and the mediating effect of climate on this change, we predicted that a positive effect of woody plants on plant C storage in semiarid grasslands may revert to a negative effect in arid grasslands. We first investigated the spatial variation of aboveground C (AGC) and belowground C (BGC) storage among grassland types and then tested our prediction. Methods We measured the living AGC storage, litter C (LC) and BGC storage of plants in two physiognomic types, wooded grasslands (aboveground biomass of woody plants at least 50%) and pure grasslands without woody plants in six grassland types representing a gradient form semiarid to arid conditions across Xinjiang. Important Findings Living AGC, LC, BGC and total plant C storage increased from desert to mountain meadows. These increases could also be explained by increasing mean annual precipitation (MAP) or decreasing mean annual temperature (MAT), suggesting that grassland types indeed represented an aridity gradient. Woody plants had an effect on the plant C storage both in size and in distribution relative to pure grasslands. The direction and strength of the effect of woody plants varied with grassland types due to the mediating effect of the climate, with wetter conditions promoting a positive effect of woody plants. Woody plants increased vegetation-level AGC through their high AGC relative to herbaceous plants. However, more negative effects of woody plants on herbaceous plants with increasing aridity led to a weaker increase in the living AGC in arid desert, steppe desert and desert steppe than in the less arid other grassland types. Under greater aridity (lower MAP and higher MAT), woody plants allocated less biomass to roots and had lower BGC and had a more negative impact on herbaceous plant production, thereby reducing vegetation-level BGC in the desert, steppe desert and desert steppe. In sum, this resulted in a negative effect of woody plants on total plant C storage in the most arid grasslands in Xinjiang. As a consequence, we predict that woody plant encroachment may decrease rather than increase C storage in grasslands under future drier conditions. more

Located in the inland arid area of central Asia, salt-affected farmlands take up one third of the total irrigated land area in Xinjiang of Northwest China. Spatio-temporal variability of soil ... salinity and the underlying mechanism are fundamental problems challenging the sustainability of oasis agriculture in China. In this study, the data of total dissolved solids（TDS） measured for soil samples collected from 27 representative study areas in the oasis areas of Xinjiang were analyzed and the coefficient of variation（CV） and stratification ratio（SR） of TDS were used to describe the lateral and vertical soil salinity variations, respectively. Weekly, monthly,and annual changes in soil salinity were also summarized. Results showed that the top（0–20 cm） soil salinity was highly variable（CV〉 75%） for most studied areas. Lateral variation of soil salinity was significantly correlated with the sampling interval; as a result, a maximum sampling interval of 0.9 m was found for reducing evaluation uncertainty. The top 0–20 cm soil salt accounted for about 25.2% of the total salt in the 0–100 cm soil profile. The stratification ratio values（the ratio of TDS at the 20–40 cm depth to that at the 0–20 cm depth） were mostly smaller than 1 and on average 0.92, illustrating that the top 0–20 cm soil contained slightly more salt and a considerable amount of salt still existed in subsurface and deep horizons. Irrigation reduced top soil salinity by 0.52 g kg^-1, or14.6%, within the first week. On average, the relative range of soil salinity, calculated to indicate monthly changes in soil salinity, was58.2% from May to September. A 27-year experiment indicated that cultivation increased soil salinity by 44.4% at a rate of 0.14 g kg^-1 year^-1. At small spatio-temporal scales, soil salinity variation was mainly affected by anthropogenic factors, such as irrigation and land use. However, natural factors, including groundwater, topography, and climate conditions, mainly influenced soil salinity variation at large spatio-temporal scales. This study displayed the highly variable nature of soil salinity in space and time. Those driving factors identified in this study could provide guidelines for developing sustainable agriculture in the oasis areas and combating salinization in arid regions of China. more

为探讨磷肥品种和施磷方式对灌耕草甸土无机磷形态和有效磷含量的影响，设置重过磷酸钙基施（TSP-B）、磷酸一铵基施（MAP-B）、聚磷酸铵基施（APP-B）、磷酸一铵滴施（MAP-D）、聚磷酸铵滴施（APP-D）和不施磷肥（CK）6个处理，室内培养120d分别测定各土层无机磷和有效磷含量。结果表明：三种磷肥基施处理显著提升5~20cm土层无机磷总量以及0~20cm土层有效磷和Ca2-P含量，而Ca8-P含量仅在5~10cm土层中显著增加（P<0.05）。TSP-B和MAP-B处理显著增加了0~5cm和10~20cm土层中Fe-P含量以及5~10cm和10~20cm土层中Al-P含量（P<0.05）。与MAP-B和APP-B处理相比，MAP-D和APP-D处理均显著增加了0~5cm土层中无机磷总量及有效磷、Ca2-P和Ca8-P含量，且APP-D处理无机磷总量、有效磷含量和Ca2-P含量均显著高于MAP-D处理（P<0.05）。灌耕草甸土无机磷中Ca10-P和O-P占比最高，分别占无机磷总量的37.6%和35.7%，Ca8-P、Al-P和Fe-P分别占14.0%、6.2%和4.8%，Ca2-P仅占1.7%。Ca2-P、Ca8-P、Al-P和O-P与有效磷呈显著正相关（P<0.05），其贡献顺序为Ca2-P>Ca8-P>Al-P>O-P。研究表明，磷肥基施可明显提高灌耕草甸土耕层（0~20cm）中无机磷总量和有效磷含量，而滴施仅能提高其表层（0~5cm）无机磷总量和有效磷含量。无机磷中Ca10-P和O-P含量最高，其后依次为Ca8-P、Al-P、Fe-P和Ca2-P。对于深根系作物，磷肥应以基施为主，宜选用价格相对较低的酸性的TSP；对于浅根系作物（<5cm），可采用磷肥滴施方式，且聚磷酸铵滴施效果优于磷酸-铵。 This study aimed to investigate the effects of phosphorus fertilizer varieties and application methods on inorganic phosphorus （IP）and available phosphorus（AP）content in irrigated meadow soil, in order to provide a decision-making basis for rational phospho

In the present study, alfalfa canopy reflectance was researched at alfalfa squaring period under different irrigation amount at the hutubi county grassland ecological station. Determining the ... spectral diagnostic model of alfalfa leaf moisture content was determined by spectrometry. The results showed that (1) The spectral reflectance of alfalfa canopy gradually decreases with the increase in the leaf water content in the near infrared. (2) The spectral inversion model of alfalfa leaf moisture content established by normalized reflectance spectra is superior to the original reflectance spectra, and the prediction model established in the 1,344-1,660 nm band has the lowest average relative error (7.8%). (3) In this study, the spectral diagnostic model of the leaf moisture content is: Y=0.962 - 7.560X1451 + 5.295X1473. The spectral prediction model of the alfalfa leaf moisture content can provide a basis for decision making for scientific irrigation of alfalfa. more

BACKGROUND 5-Fluorouracil (5-FU) based treatment is the standard therapy for metastatic colorectal cancer (CRC), but the development of chemoresistance is inevitable. Increasing evidence shows that ... dysregulation of microRNAs (miRNAs) is involved in malignant transformation. Thus, it is imperative that we find new diagnostic and prognostic marker for chemotherapy in CRC. MATERIAL AND METHODS For clinical parameter analysis, 78 CRC tissues and adjacent normal tissues and 45 serum specimens from CRC patients were included in this study. For chemo-response analysis, 116 primary tissues were collected from the patients receiving first-line 5-FU treatment. Quantitative Real-Time PCR (qRT-PCR) was used to detect microRNAs expression. RESULTS The expression of miR-429 was significantly increased in both serum and primary tissues from CRC patients, and enhanced miR-429 level was associated with tumor size, lymph node metastasis, and TNM stage. The diagnostic and prognostic values were also confirmed in CRC by using primary tissues. For patients receiving 5-FU-based treatment, miR-429 levels were significantly lower in responding group. The proportions of patients that did not experience response to therapy were higher in primary tumors with high miR-429 expression levels as compared with primary tumors with low miR-429 expression levels. Finally, Kaplan-Meier survival analysis showed that miR-429 is an independent prognostic indicator for chemo-response to 5-FU therapy among CRC patients. CONCLUSIONS High level of miR-429 expression was correlated with enhanced malignant potential and poor prognosis of CRC patients. Furthermore, miR-429 could affect the chemo-sensitivity of CRC patients to 5-FU therapy and was associated with poor response to 5-FU-based chemotherapy in patients with CRC. more

Through the atom absorption and emission spectrum analysis, it is detected 8 trace elements contents in eleven species of melons and fruits in Xinjiang. On comparative analysis with biological ... standard of China, it is found that the zinc quantity in apples is 66.75 mg x kg(-1), the strontium quantity in jujubes is 8.62 mg x kg(-1) and Chinese-date contains strontium 8.62 mg x kg(-1) in Hetian area; and that in the Kuerle area the pomegranate is potassium 687 mg x kg, in Hami Territory Chinese-date contains manganese, zinc, strontium, calcium, iron, potassium and nickel, all of them are more over the national biological standard. The contents of copper in eleven species of melons and fruits are lower than the biological standard of China The average contents of 8 kind microelement in the pomegranate of Kuerle, in the apples of Hetian, the Chinese-date of Hami are very high (respectively to be 91.82, 121.5 and 275.3 mg x kg(-1)), and in the watermelon of Wujiaqu, the pericarp (54.19 mg x kg(-1)) take place high more

The changes in three endogenous hormones, phytohormones gibberrelic acid (GA3), indoles-3-acid (IAA) and abscisic acid (ABA), were studied around germination and under tress of different density of ... Pb2+ between two species of Ammopiptanathus. It was found that (1) around germination, in Xinjiang Ammopiptanthus the rate IAA decreased 77.80%, and the rate of ABA decreased 98.90%; and in Mongolia Ammopiptanthus the rate of IAA decreased 75.80%, the rate of ABA decreased 66.20%, and the GA3 contents in both had no big change. (2) With the increase in Pb2+ concentration (20-1 500 mg x L(-1)), the IAA decreased significantly; and only under the high density (more than 1 000 mg x L(-1)) of Pb2+, the GA3 was affected by it; the ABA did not change regularly. So the three endogenous hormone levels of Mongolia Ammopiptanthus were higher than those of Xinjiang Ammopiptanthus. (3) the distributions of Pb2+ in Ammopiptanthus seedlings are the root > stems > leaves. (4) the stress of high concentration of Pb2+ damages irrev more