Exogenous Streptomyces spp. enhance the drought resistance of naked oat (Avena nuda) seedlings by augmenting both the osmoregulation mechanisms and antioxidant capacities.

Drought is a major obstacle to the development of naked oat industry. This work investigated mechanisms by which exogenous Streptomyces albidoflavus T4 and Streptomyces rochei D74 improved drought tolerance in naked oat (Avena nuda ) seedlings. Results showed that in the seed germination experiment, germination rate, radicle and hypocotyl length of naked oat seeds treated with the fermentation filtrate of T4 or D74 under PEG induced drought stress increased significantly. In the hydroponic experiment, the shoot and root dry weights of oat seedlings increased significantly when treated with the T4 or D74 fermentation filtrate under the 15% PEG induced drought stress (S15). Simultaneously, the T4 treatment also significantly increased the surface area, volume, the number of tips and the root activity of oat seedlings. Both T4 and D74 treatments elicited significant increases in proline and soluble sugar contents, as well as the catalase and peroxidase activities in oat seedlings. The results of comprehensive drought resistance capacity (CDRC) calculation of oat plants showed that the drought resistance of oat seedlings under the T4 treatment was better than that under the D74 treatment, and the effect was better under higher drought stress (S15). Findings of this study may provide a novel and effective approach for enhancing plant defenses against drought stress.

Moderate organic fertilizer substitution for partial chemical fertilizer improved soil microbial carbon source utilization and bacterial community composition in rain-fed wheat fields: current year.

Organic fertilizers can partially replace chemical fertilizers to improve agricultural production and reduce negative environmental impacts. To study the effect of organic fertilizer on soil microbial carbon source utilization and bacterial community composition in the field of rain-fed wheat, we conducted a field experiment from 2016 to 2017 in a completely randomized block design with four treatments: the control with 100% NPK compound fertilizer (N: P2O5: K2O = 20:10:10) of 750 kg/ha (CK), a combination of 60% NPK compound fertilizer with organic fertilizer of 150 kg/ha (FO1), 300 kg/ha (FO2), and 450 kg/ha (FO3), respectively. We investigated the yield, soil property, the utilization of 31 carbon sources by soil microbes, soil bacterial community composition, and function prediction at the maturation stage. The results showed that (1) compared with CK, organic fertilizer substitution treatments improved ear number per hectare (13%-26%), grain numbers per spike (8%-14%), 1000-grain weight (7%-9%), and yield (3%-7%). Organic fertilizer substitution treatments increased the total nitrogen, available nitrogen, available phosphorus, and soil organic matter contents by 26%, 102%, 12%, and 26%, respectively, compared with CK treatments. Organic fertilizer substitution treatments significantly advanced the partial productivity of fertilizers. (2) Carbohydrates and amino acids were found to be the most sensitive carbon sources for soil microorganisms in different treatments. Particularly for FO3 treatment, the utilization of ß-Methyl D-Glucoside, L-Asparagine acid, and glycogen by soil microorganisms was higher than other treatments and positively correlated with soil nutrients and wheat yield. (3) Compared with CK, organic fertilizer substitution treatments increased the relative abundance of Proteobacteria, Acidobacteria, and Gemmatimonadetes and decreased the relative abundance of Actinobacteria and Firmicutes. Interestingly, FO3 treatment improved the relative abundance of Nitrosovibrio, Kaistobacter, Balneimonas, Skermanella, Pseudomonas, and Burkholderia belonging to Proteobacteria and significantly boosted the relative abundance of function gene K02433 [the aspartyl-tRNA (Asn)/glutamyl-tRNA (Gln)]. Based on the abovementioned findings, we suggest FO3 as the most appropriate organic substitution method in rain-fed wheat fields.

Hydrogen sulfide alleviates chromium toxicity by promoting chromium sequestration and re-establishing redox homeostasis in Zea mays L.

Hydrogen sulfide (H2S) is a multifunctional gaseous signaling molecule involved in the regulation of Cr stress responses. In the present study, we combined transcriptomic and physiological analyses to elucidate the mechanism underlying the mitigation of Cr toxicity by H2S in maize (Zea mays L.). We showed that treatment with sodium hydrosulfide (NaHS, a donor of H2S) partially alleviated Cr-induced growth inhibition. However, Cr uptake was not affected. RNA sequencing suggested that H2S regulates the expression of many genes involved in pectin biosynthesis, glutathione metabolism, and redox homeostasis. Under Cr stress, NaHS treatment significantly increased pectin content and pectin methylesterase activity; thus, more Cr was retained in the cell wall. NaHS application also increased the content of glutathione and phytochelatin, which chelate Cr and transport it into vacuoles for sequestration. Furthermore, NaHS treatment mitigated Cr-induced oxidative stress by enhancing the capacity of enzymatic and non-enzymatic antioxidants. Overall, our results strongly support that H2S alleviates Cr toxicity in maize by promoting Cr sequestration and re-establishing redox homeostasis rather than by reducing Cr uptake from the environment.

Exogeneous selenium enhances anthocyanin synthesis during grain development of colored-grain wheat.

Anthocyanins and selenium (Se) play critical roles in antioxidant, anticancer, antibacterial, and antiviral treatments. Previous studies indicate that colored-grain wheat accumulates more Se than regular wheat, and Se synergistically promotes anthocyanin synthesis. However, the mechanism through which Se regulates anthocyanin synthesis remains unclear. We studied anthocyanin accumulation during the grain-filling stage of colored-grain wheat development by employing transcriptomics and metabolomics. We show that Se biofortification increased the concentrations of Se, anthocyanin, chlorophyll a and b, and carotenoids in colored-grain wheat. Genes related to biosynthesis of anthocyanins, phenylpropanoids biosynthesis, and flavonoids biosynthesis were significantly upregulated after Se treatment, which led to the accumulation of anthocyanin metabolites in colored-grain wheat. Genetic alterations in the expression profiles of several genes and transcription factors were observed, which slowed down lignin and proanthocyanidin biosynthesis and accelerated anthocyanin synthesis. Our results deepen the understanding of anthocyanin metabolism in Se-treated colored-grain wheat, which will likely promote harvest of these varieties.

Melatonin Alleviates Chromium Toxicity in Maize by Modulation of Cell Wall Polysaccharides Biosynthesis, Glutathione Metabolism, and Antioxidant Capacity.

Melatonin, a pleiotropic regulatory molecule, is involved in the defense against heavy metal stress. Here, we used a combined transcriptomic and physiological approach to investigate the underlying mechanism of melatonin in mitigating chromium (Cr) toxicity in Zea mays L. Maize plants were treated with either melatonin (10, 25, 50 and 100 µM) or water and exposed to 100 µM K2Cr2O7 for seven days. We showed that melatonin treatment significantly decreased the Cr content in leaves. However, the Cr content in the roots was not affected by melatonin. Analyses of RNA sequencing, enzyme activities, and metabolite contents showed that melatonin affected cell wall polysaccharide biosynthesis, glutathione (GSH) metabolism, and redox homeostasis. During Cr stress, melatonin treatment increased cell wall polysaccharide contents, thereby retaining more Cr in the cell wall. Meanwhile, melatonin improved the GSH and phytochelatin contents to chelate Cr, and the chelated complexes were then transported to the vacuoles for sequestration. Furthermore, melatonin mitigated Cr-induced oxidative stress by enhancing the capacity of enzymatic and non-enzymatic antioxidants. Moreover, melatonin biosynthesis-defective mutants exhibited decreased Cr stress resistance, which was related to lower pectin, hemicellulose 1, and hemicellulose 2 than wild-type plants. These results suggest that melatonin alleviates Cr toxicity in maize by promoting Cr sequestration, re-establishing redox homeostasis, and inhibiting Cr transport from the root to the shoot.

Selenium Application Enhances the Accumulation of Flavones and Anthocyanins in Bread Wheat (Triticum aestivum L.) Grains.

Selenium (Se) biofortification in wheat reduces the risk of Se deficiency in humans. Se biofortification increases the concentration of Se and anthocyanins in wheat grains. However, it is unknown whether Se biofortification can enhance flavonoids other than anthocyanins and the mechanism underlying flavonoid accumulation in wheat grains. Here, foliar application of selenite solution in wheat was conducted 10 days after flowering. Metabolite profiling and transcriptome sequencing were performed in Se-treated grains. A significant increase in the total contents of Se, anthocyanins, and flavonoids was observed in Se-treated mature grains. Twenty-seven significantly increased flavonoids were identified in Se-treated immature grains. The significant accumulation of flavones (tricin, tricin derivatives, and chrysoeriol derivatives) was detected, and six anthocyanins, dihydroquercetin (the precursor for anthocyanin biosynthesis) and catechins were also increased. Integrated analysis of metabolites and transcriptome revealed that Se application enhanced the biosynthesis of flavones, dihydroquercetin, anthocyanins, and catechins by increasing the expression levels of seven key structural genes in flavonoid biosynthesis (two TaF3Hs, two TaDFRs, one TaF3'5'H, one TaOMT, and one TaANR). Our findings shed new light on the molecular mechanism underlying the enhancement in flavonoid accumulation by Se supplementation and pave the way for further enhancing the nutritional value of wheat grains.

Melatonin alleviates aluminum-induced growth inhibition by modulating carbon and nitrogen metabolism, and reestablishing redox homeostasis in Zea mays L.

Melatonin, a regulatory molecule, performs pleiotropic functions in plants, including aluminum (Al) stress mitigation. Here, we conducted transcriptomic and physiological analyses to identify metabolic processes associated with the alleviated Al-induced growth inhibition of the melatonin-treated (MT) maize (Zea mays L.) seedlings. Melatonin decreased Al concentration in maize roots and leaves under Al stress. Al stress reduced the total dry weight (DW) by 41.2% after 7 days of treatment. By contrast, the total DW was decreased by only 19.4% in MT plants. According to RNA-Seq, enzyme activity, and metabolite content data, MT plants exhibited a higher level of relatively stable carbon and nitrogen metabolism than non-treated (NT) plants. Under Al stress, MT plants showed higher photosynthetic rate and sucrose content by 29.9% and 20.5% than NT plants, respectively. Similarly, the nitrate reductase activity and protein content of MT plants were 34.0% and 15.0% higher than those of NT plants, respectively. Furthermore, exogenous supply of melatonin mitigated Al-induced oxidative stress. Overall, our results suggest that melatonin alleviates aluminum-induced growth inhibition through modulating carbon and nitrogen metabolism, and reestablishing redox homeostasis in maize. Graphical Abstarct.

Effects of fallow tillage on winter wheat yield and predictions under different precipitation types.

In northern China, precipitation that is primarily concentrated during the fallow period is insufficient for the growth stage, creates a moisture shortage, and leads to low, unstable yields. Yield prediction in the early growth stages significantly informs field management decisions for winter wheat (Triticum aestivum L.). A 10-year field experiment carried out in the Loess Plateau area tested how three tillage practices (deep ploughing (DP), subsoiling (SS), and no tillage (NT)) influenced cultivation and yield across different fallow periods. The experiment used the random forest (RF) algorithm to construct a prediction model of yields and yield components. Our results revealed that tillage during the fallow period was more effective than NT in improving yield in dryland wheat. Under drought condition, DP during the fallow period achieved a higher yield than SS, especially in drought years; DP was 16% higher than SS. RF was deemed fit for yield prediction across different precipitation years. An RF model was developed using meteorological factors for fixed variables and soil water storage after tillage during a fallow period for a control variable. Small error values existed in the prediction yield, spike number, and grains number per spike. Additionally, the relative error of crop yield under fallow tillage (5.24%) was smaller than that of NT (6.49%). The prediction error of relative meteorological yield was minimum and optimal, indicating that the model is suitable to explain the influence of meteorological factors on yield.

Rhizosphere soil properties, microbial community, and enzyme activities: Short-term responses to partial substitution of chemical fertilizer with organic manure.

The partial substitution of chemical fertilizers with organic manure has positive effects on crop productivity and sustainable development. Nevertheless, few studies have focused on major grain crops. Herein, we report the short-term effects of the partial substitution of chemical fertilizers with organic manure on the physicochemical properties, microbial community, and enzyme activities in the rhizosphere soil of a maize (Zea mays L.) field. A decrease in soil bulk density, pH, and electrical conductivity, concomitant with an increase in soil urease, invertase, and alkaline phosphatase activities, and a high level of nutrients were observed in organic manure-treated soil. The influence of the organic substitution treatment on bacterial diversity was greater than that on fungal diversity, particularly on alpha diversity. Among dominant bacterial phyla, Actinobacteria abundance changed the most, with significantly increase under organic manure treatment. In turn, among fungi, only Ascomycota responded substantially to organic substitution. Binding spatial ordination analysis revealed that relative soil water content and soil organic carbon, and nitrate and total nitrogen contents had a stronger effect on bacteria and fungi, respectively, than any other soil physicochemical property. Additionally, the changes in bacterial and fungal communities influenced soil enzymatic activities. Moreover, partial least squares path model revealed that soil physicochemical properties indirectly affected soil enzymatic activities by their direct effects on microbial (both bacteria and fungi) community. Overall, our results indicate that the substitution of chemical fertilizers by organic manure changed the composition of the soil microbial community, and that the effects of the substitution were more significant on bacteria than on fungi.

Combined foliar and soil selenium fertilizer improves selenium transport and the diversity of rhizosphere bacterial community in oats.

Agronomic selenium (Se) biofortification of grain crops is considered the best method for increasing human Se intake, which may help people alleviate Se-deficiency. To investigate the efficiency of agronomic Se biofortification of oat, four Se fertilizer application treatments were tested: topsoil (T), foliar (S), the combination of T and S (TS), and control without Se application (CK). Compared with CK, TS significantly increased the 1000-grain weight, grain yield, Se contents in all parts of oats, contents of soil available N, K, and organic matter by 18%, 8.70%, 19.7-60.2%, 6.00%, 8.02%, and 17.95%, respectively. Leaves, roots, and ears had the highest conversion rate of exogenous Se in S (644.63%), T (416.00%), and TS (273.20%), respectively. TS also increased the activities of soil urease, alkaline phosphatase, and sucrose and the diversity of soil bacterial communities. TS and T increased the relative abundance of bacteria involved in the decomposition of organic matter, such as Actinobacteria, Gemmatimonadetes, Chloroflexi, and Bacteroidetes positively correlated with soil nutrients and enzyme activities, and reduced Proteobacteria and Firmicutes negatively correlated with them, Granulicella, Bacillus, Raoultella, Lactococcus, Klebsiella, and Pseudomonas. Furthermore, TS significantly increased the relative abundance of Planctomycetes, Chlorobi, Nitrospinae, Nitrospirae, Aciditeromonas, Gemmatimonas, Geobacter, and Thiobacter. T significantly increased the abundance of Lysobacter, Holophaga, Candidatus-Koribacter, Povalibacter, and Pyrinomonas. S did not significantly change the bacterial communities. Thus, a combined foliar and soil Se fertilizer proved conducive for achieving higher yield, grain Se content, and improving Se transport, the diversity of rhizosphere bacterial community, and bacterial functions in oats.

Combined IFN-γ and IL-2 release assay for detect active pulmonary tuberculosis: a prospective multicentre diagnostic study in China.

BACKGROUND: We performed a prospective multicentre diagnostic study to evaluate the combined interferon-γ (IFN-γ) and interleukin-2 (IL-2) release assay for detect active pulmonary tuberculosis (TB) in China. METHODS: Adult patients presenting symptoms suggestive of pulmonary TB were consecutively enrolled in three TB-specialized hospitals. Sputum specimens and blood sample and were collected from each participant at enrolment. The levels of Mycobacterium tuberculosis (MTB)-specific antigen-stimulated IFN-γ and IL-2 were determined using enzyme-linked immunosorbent assay (ELISA). RESULTS: Between July 2017 and December 2018, a total of 3245 patients with symptoms suggestive of pulmonary TB were included in final analysis. Of 3245 patients, 2536 were diagnosed as active TB, consisting of 1092 definite TB and 1444 clinically diagnosed TB. The overall sensitivity and specificity of IFN-γ were 83.8% and 81.5%, respectively. In addition, compared with IFN-γ, the specificity of IL-2 increased to 94.3%, while the sensitivity decreased to 72.6%. In addition, the highest sensitivity was achieved with parallel combination of IFN-γ/IL-2, with a sensitivity of 87.9%, and its overall specificity was 79.8%. The sensitivity of series combination test was 68.5%. Notably, the sensitivity of series combination test in definite TB (72.1%) was significantly higher than that in clinically diagnosed TB (65.8%). CONCLUSION: In conclusion, we develop a new immunological method that can differentiate between active TB and other pulmonary diseases. Our data demonstrates that the various IFN-γ/IL-2 combinations provides promising alternatives for diagnosing active TB cases in different settings. Additionally, the diagnostic accuracy of series combination correlates with severity of disease in our cohort.

Methods of Selenium Application Differentially Modulate Plant Growth, Selenium Accumulation and Speciation, Protein, Anthocyanins and Concentrations of Mineral Elements in Purple-Grained Wheat.

Selenium (Se) is an essential micronutrient for human health. Deficiency and suboptimality of Se in human populations are a potential health risk. The reduction of such health risk by biofortification of crops, particularly in wheat has drawn much attention, especially for color-grained wheat as it is rich in anthocyanins and can be used as a major source of antioxidants in diet. Herein, a two-year field study on the purple-grained wheat cultivar (202w17) and common wheat cultivar (Shannong 129) was conducted with soil application (SeS) and foliar spray (SeF) of selenium. Results showed that the SeS increased shoot dry weight and grain yield. Both SeS and SeF enhanced the concentration of organic Se, but the higher concentration of organic Se in the grain of two cultivars was observed in SeF in comparison with SeS. The concentration of organic Se in the grain of 202w17 treated with SeF was approximately 1.5-fold of that in Shannong 129 with SeF. The analysis of Se accumulation in different parts of the plant revealed that 202w17 accumulated more Se in shoots and grain than Shannong 129, and 202w17 had also higher levels of total protein, total free amino acids and anthocyanin in grain than Shannong 129. In addition, SeF significantly increased the concentrations of zinc (Zn), calcium (Ca), magnesium (Mg) in both cultivars, but decreased the concentration of chromium (Cr), cadmium (Cd) and lead (Pd), which phenomenon was more significant in 202w17. Our results indicate that SeS increases plant growth, leading to higher grain yield in two cultivars tested. The purple-grained wheat (202w17) could accumulate more Se in grain and have a higher concentration of orgainic Se in grain than the common wheat (Shannong 129).

Soil water consumption, water use efficiency and winter wheat production in response to nitrogen fertilizer and tillage.

Sustainability of winter wheat yield under dryland conditions depends on improving soil water stored during fallow and its efficient use. A 3-year field experiment was conducted in Loess Plateau to access the effect of tillage and N (nitrogen) rates on soil water, N distribution and water- and nitrogen-use efficiency of winter wheat. Deep tillage (DT, 25-30 cm depth) and no-tillage (NT) were operated during fallow season, whereas four N rates (0, 90, 150 and 210 kg ha-1) were applied before sowing. Rates of N and variable rainfall during summer fallow period led to the difference of soil water storage. Soil water storage at anthesis and maturity was decreased with increasing N rate especially in the year with high precipitation (2014-2015). DT has increased the soil water storage at sowing, N content, numbers of spike, grain number, 1,000 grain weight, grain yield, and water and N use efficiency as compared to NT. Grain yield was significantly and positively related to soil water consumption at sowing to anthesis and anthesis to maturity, total plant N, and water-use efficiency. Our study implies that optimum N rate and deep tillage during the fallow season could improve dryland wheat production by balancing the water consumption and biomass production.

Responses of rhizosphere soil bacteria to 2-year tillage rotation treatments during fallow period in semiarid southeastern Loess Plateau.

BACKGROUND: Soil compaction can be mitigated by deep tillage and subsoiling practices following a long period of no-tillage. Fallow tillage rotation methods are frequently used to improve water availability in the soils of the southeastern Loess Plateau region of China. Rhizosphere soil bacteria are ecologically important for the transformation of matter and energy in the plant root system and can be influenced by tillage rotation treatments. However, the effect of tillage rotations on the bacterial community and structure of rhizosphere soil is not well understood. METHODS: A two-year field experiment was conducted with four tillage rotation treatments, including subsoil-subsoil (SS-SS), subsoil-deep tillage (SS-DT), deep tillage-deep tillage (DT-DT), and the control treatment of no-tillage-no-tillage (NT-NT). Our study was conducted during wheat's fallow period to investigate the abundance, diversity, and functions of rhizosphere soil bacteria using high-throughput sequencing technology. RESULTS: Our results showed that tillage rotation methods significantly influenced the bacterial diversity and composition of the rhizosphere soil in the plough layer (20-40 cm depth) by altering the moisture content of the soil. The metabolism, environmental information processing, and genetic information processing of the bacteria in the rhizosphere soil were affected. The most abundant phyla across all samples were Proteobacteria, Actinobacteria, Acidobacteria, Planctomycetes, Bacteroidetes, Gemmatimonadetes, Frimicutes, Chloroflexi, Nitrospirae, and Verrucomicrobia, which are classic bacterial decomposers in soil. The bacterial diversity and composition was similar for treatments causing higher soil perturbation (SS-DT and DT-DT), which disrupted the balance between aerobic and anaerobic bacteria. The less disruptive tillage methods (SS-SS and NT-NT), preserved the integrity of the soil bacteria. However, the NT-NT treatment may have led to soil compaction, particularly in the 20-40 cm layer. These results suggested that SS-SS was the most effective tillage rotation practice to accumulate soil moisture, maintain the balance between aerobic and anaerobic bacteria, and to enhance the metabolic capacity of rhizosphere soil bacteria. This method may have a significant impact on the sustainable development and farming practices of dryland agriculture.

Sowing Methods Influence Soil Bacterial Diversity and Community Composition in a Winter Wheat-Summer Maize Rotation System on the Loess Plateau.

Soil bacterial diversity and community composition are crucial for soil health and plant growth, and their dynamics in response to agronomic practices are poorly understood. The aim of this study was to investigate the response of soil bacterial community structure to the changes of sowing methods, soil depth and distance to roots in a winter wheat-summer maize crop rotation system on the Loess Plateau in china (35°17'38''N, 111°40'24''E). The experiment was laid out as completely randomized block design with three replications. Sowing methods trialed were: traditional sowing (TS), film-mulched ridge and furrow sowing (FMR&F), wide ridge and narrow furrow sowing (WR&NF) and unplanted control (CK). The result showed that the WR&NF sowing method treatment significantly decreased soil bacterial diversity (Chao 1 and Shannon indices) compared to the TS and FMR&F treatment, but increased abundance of beneficial bacteria such as genera Bacillus and Pseudomonas compared to the TS treatment. These genera showed a stronger correlation with soil properties and contributed to the soil nutrient cycling and crop productivity. Bacillus, Pseudomonas, Nevskia, and Lactococcus were the keystone genera in this winter wheat-summer maize rotation system on the Loess Plateau. Strong correlations between changes in soil properties and soil bacterial diversity and abundance were identified. In summary, we suggest that the WR&NF treatment, as a no-mulching film and no-deep tillage sowing method, would be the most suitable sowing technique in the winter wheat-summer maize rotation on Loess soil.

[Effects of sowing date and seeding rate on soil water consumption and plant nitrogen translocation in dryland wheat]. / æ’­æœŸæ’­é‡å¯¹æ—±åœ°å°éº¦åœŸå£¤æ°´åˆ†æ¶ˆè€—å’Œæ¤æ ªæ°®ç´ è¿è½¬çš„å½±å“.

To tackle the issue of rainfall delay during dryland wheat sowing season and further examine the effects of seeding rate on water use and yield formation, a field experiment was conducted at Wenxi Experimental Station, Shanxi Province between 2015 and 2017. We used two sowing dates, i.e. September 20 and October 10 as early (EB) and late (LB) sowing in main plots, and each with three seeding rates as 67.5 (LD), 90 (MD) and 112.5(HD) kg·hm-2. The results showed that compared with LB, EB increased total soil water consumption by 11-22 mm over the entire growing season. With the increases of seeding density, total soil water consumption increased by 2-20 mm. Soil water consumption before anthesis tended to increase for LB, while there was a significant increase of soil water consumption after anthesis for EB. Compared with LB, the pre-anthesis nitrogen translocation and post-anthesis nitrogen accumulation amount in EB were increased under LD and MD, but decreased under HD. For EB, the pre-anthesis nitrogen translocation amount and post-anthesis nitrogen accumulation amount were highest at LD. Under LB, the pre-anthesis nitrogen translocation amount and post-anthesis nitrogen accumulation amount were greatest at high sowing density. EB significantly increased grain yield by 163-996 kg·hm-2 than LB. EB significantly increased grain yield and water use efficiency by 5%-26% and 2%-21% compared with LB, respectively. The nitrogen absorption efficiency and harvest index were 3%-36% and 11% higher under LB than that under EB. As for seeding rate, a low level tended to gain higher grain yield, water use efficiency, nitrogen uptake efficiency and nitrogen harvest index under EB, whereas a high level tended to gain higher values of grain yield, water use efficiency, nitrogen uptake efficiency and nitrogen harvest index under LB. In addition, the pre-anthesis nitrogen translocation was closely related with 100-200 cm soil water consumption before anthesis, especially for stem + sheath, glume + spike nitrogen translocation. The post-anthesis nitrogen accumulation was significantly correlated with 100-300 cm soil water consumption after anthesis. In conclusion, early sowing with a seeding rate of 67.5 kg·hm-2 and late sowing with a seeding rate of 112.5 kg·hm-2 could be promising options to boost dryland wheat production.

Development of Drought-Tolerant Transgenic Wheat: Achievements and Limitations.

Crop yield improvement is necessary to keep pace with increasing demand for food. Due to climatic variability, the incidence of drought stress at crop growth stages is becoming a major hindering factor to yield improvement. New techniques are required to increase drought tolerance along with improved yield. Genetic modification for increasing drought tolerance is highly desirable, and genetic engineering for drought tolerance requires the expression of certain stress-related genes. Genes have been identified which confer drought tolerance and improve plant growth and survival in transgenic wheat. However, less research has been conducted for the development of transgenic wheat as compared to rice, maize, and other staple food. Furthermore, enhanced tolerance to drought without any yield penalty is a major task of genetic engineering. In this review, we have focused on the progress in the development of transgenic wheat cultivars for improving drought tolerance and discussed the physiological mechanisms and testing of their tolerance in response to inserted genes under control or field conditions.

The performance of T-cell Xtend reagent in increasing blood storage times for interferon gamma release assays.

BACKGROUND: T-cell Xtend (TCX) was introduced to extend the blood storage time for T-SPOT.TB test, a widely used commercial interferon gamma release assay (IGRA) for rapid in vitro tuberculosis. METHODS: A total of 99 Uyghur suspected tuberculosis patients were recruited in this study. T-SPOT.TB test was performed with fresh blood (controls), 36 hours delayed blood and delayed and TCX-treated (at 36 hours) blood from each patient, respectively. RESULTS: White blood cells and lymphocytes proportion in peripheral blood mononuclear cells s and spot-forming cells in positive control wells decreased significantly in delayed blood samples when compared with controls, while this decrease was not detected in TCX-treated group. In the 58 patients with paired T-SPOT.TB results of three groups of samples, a higher positive rate was observed in TCX-treated group than both in controls and untreated group (41.4% vs 37.9% and 25.9%). The concordance of T-SPOT.TB results between the treated group and controls was 0.856, whereas the agreement between controls and untreated group was unsatisfactory (0.649). In the 23 elderly patients (>70 years old) with paired T-SPOT.TB results of controls and TCX group, treated group showed a non-significant trend toward higher positive rate than controls (43.5% vs 26.1%, P=.22). Meanwhile, TCX treatment reduced the risk of false negative T-SPOT.TB results in the elderly population. CONCLUSION: Deterioration of blood sample caused by long storage time can be neutralized by TCX treatment. The results provide data for the utility of TCX in a novel population and in Asian region, and reveal the potential of TCX to improve the accuracy of T-SPOT.TB test in elderly population.

A globally convergent QP-free algorithm for nonlinear semidefinite programming.

In this paper, we present a QP-free algorithm for nonlinear semidefinite programming. At each iteration, the search direction is yielded by solving two systems of linear equations with the same coefficient matrix; [Formula: see text] penalty function is used as merit function for line search, the step size is determined by Armijo type inexact line search. The global convergence of the proposed algorithm is shown under suitable conditions. Preliminary numerical results are reported.

Palladium-catalyzed allylation of sulfonyl hydrazides with alkynes to synthesize allylic arylsulfones.

A novel method for the construction of allyl arylsulfone derivatives was developed by palladium catalyzed allylation of sulfonyl hydrazides with alkynes. A series of structurally diverse allyl arylsulfones can be regioselectively synthesized in high yields under mild conditions.