Search

The recently discovered complete ammonia oxidizers (comammox Nitrospira) have fundamentally changed the perceptions of two-step nitrification. Previous studies suggest that comammox Nitrospira may outcompete canonical ammonia oxidizers under ammonia-limited conditions (e.g., acidic soils). However, there is no convincing evidence that links comammox Nitrospira activity to nitrification in acidic soils. Here, we report the relative contributions of ammonia-oxidizing bacteria (AOB), archaea (AOA), and comammox Nitrospira to nitrification in four orchard soils with different ages (5Y, 10Y, 20Y, and 30Y) and one adjacent natural forest soil (NF) in China. DNA-based stable-isotope probing demonstrated that both AOA and AOB assimilated 13CO2 in the nonacidic NF, 5Y, and 10Y soils, although a small shift from the light fractions to heavy fractions was observed for comammox Nitrospira clade A in the 10Y soil. Comammox Nitrospira clade A rather than AOA and AOB was labeled by 13CO2 in strongly acidic 30Y soil. In strongly acidic 20Y soil, comammox Nitrospira clade A was much more heavily labeled than AOB. These results suggest the different contributions of ammonia oxidizers to nitrification in orchard soils with different ages and a greater functional importance of comammox Nitrospira than canonical ammonia oxidizers in ammonia oxidation in the tested strongly acidic orchard soils. [ABSTRACT FROM AUTHOR]

Wood defect identification plays an essential role in guaranteeing the quality and efficiency of furniture manufacturing, which is a challenging task due to the data complexity and high-efficiency requirements. This paper proposes an improved ResNet-50-based modeling method to enhance the accuracy and efficiency of defect identification on wood surfaces. Firstly, a new optimization scheme integrating a convolutional block attention module and the cross-stage partial network (CSPNet) was developed for ResNet-50. Besides, the impacts of cross-stage parameter in CSPNet's classification performance are experimentally investigated, and it is demonstrated that the default cross-stage parameter in CSPNet is not always optimal. Furthermore, a ranger optimizer is proposed to obtain proper network parameters, which outperforms the traditional Adam optimizer with respect to training efficiency and prediction accuracy. Experiments are carried out on the image dataset collected from real-world wood surface defects. The experimental results illustrated that the proposed model achieves better defects on wood surfaces than state-of-the-art methods, with an overall detection accuracy of 86.25% in detecting knots, cracks, and color-related defects in images. These results demonstrate the effectiveness and feasibility of the proposed modeling and control method. [ABSTRACT FROM AUTHOR]

Boron (B) has previously been shown to inhibit cadmium (Cd) uptake in wheat. Here, we investigated the physiological response of external B application (C for no B added, B for B added, B+Cd for B and Cd added, B/Cd for B 24 h pretreatment before Cd added, B and Cd were 46.2 μM and 5 μM, respectively) on wheat growth under Cd stress. The results showed that the wheat growth was significantly weaker under Cd treatment, while B application did not significantly improve the wheat growth under Cd stress. However, B application decreased Cd concentrations and malondialdehyde (MDA) concentrations of shoot and root. The key enzyme activities including superoxide dismutase (SOD) and peroxidase (POD) significantly increased under Cd treatments while decreased under B treatments. Further, a total of 198, 680 and 204 of the differential metabolites were isolated between B and C treatment, Cd and C treatment and B+Cd and Cd treatment, respectively. The metabolites with up-accumulation in B application (B+Cd) roots were mainly galactaric acid, citric acid, N6-galacturonyl-L-lysine, D-glucose, while the metabolites with down-accumulation were mainly threoninyl-tryptophan and C16 sphinganine. The differential metabolic pathways were mainly concentrated in linoleic acid metabolism, galactose metabolism, sphingolipid metabolism, glycolysis/gluconeogenesis, propanoate metabolism in diabetic complications between B+Cd treatment and B treatment. The results indicate that B alleviates Cd toxicity in winter wheat by inhibiting Cd uptake, increasing antioxidant enzyme activity and changing metabolites. [ABSTRACT FROM AUTHOR]

This study aimed to investigate the effects of selenium application on cadmium absorption, transport, and soil cadmium forms of winter wheat at different stages. A pot experiment with one Cd application (6 mg·kg−1) and five Se application levels (0, 1, 2, 5, and 10 mg·kg−1) was conducted. The results showed that Se application increased the grain yield of winter wheat, especially at 5 mg·kg−1 under Cd stress. As Se was supplied at 5 (Se5) and 10 (Se10) mg·kg−1, the Cd concentrations in roots and shoots, including stems, spikes, glumes, and grains, decreased at different growth stages, and the decreases in grain were 46.1% and 70.9% respectively. Se5 and Se10 also significantly decreased the translocation factors of Cd from roots to shoots, roots to stems, stems to spikes, and glumes to grains, promoted the accumulation of Cd in roots, and inhibited the accumulation of Cd in shoots and final grains at different growth stages, and the accumulation of Cd in grains decreased by 16.9% and 68.1%, respectively. High levels of Se application (Se5 and Se10) decreased the concentrations and proportions of exchangeable Cd (EXC−Cd) and iron (Fe)−manganese (Mn) oxide−bound Cd (R2O3−Cd) but increased the concentration and proportion of residual Cd (RES−Cd) in both soils with wheat and fallow soil at different growth stages. Therefore, under Cd stress, high levels of Se application reduced the shoot Cd concentration by inhibiting the uptake and transport of Cd from roots to shoots, and decreased the bioavailability of Cd in both soil with wheat and fallow by enhancing the transformation and distribution of RES-Cd from EXC-Cd and R2O3-Cd. [ABSTRACT FROM AUTHOR]

The objective of this study was to evaluate the effect of boron (B) fertilizer application on the yield and nutritive element content of wheat grain. A field experiment was conducted using wheat at five B treatments consisting of B0 (no B added), B0.2, B0.4, B0.8 and B1.6 (B added at 0.2, 0.4, 0.8 or 1.6 mg kg−1 B, respectively). Boric acid was added to soil to create five B concentrations. Results showed that the there was no significantly difference on yield and thousand seed weight of wheat among different B application treatments. The wheat plant showed a higher B concentration in the root, leaf and shell but lower B concentration in stem and grain. There was an increasing trend for the B concentrations in root, middle stem, leaf and grain with increasing B levels, especially B concentration in grain at B0.8 treatment. However, the translocation factors (TFs) in grain/shell is low. These results suggested that B is easily absorbed by wheats, but not easily transferred to the grain site. In addition, there was an increased tendency for calcium (Ca), magnesium (Mg), copper (Cu), iron (Fe) and zinc (Zn) concentrations with increased B treatment. Grey correlation model analysis showed that the synthetic characteristics of grain (expressed as grey relation degree) followed the sequence of B1.6 > B0.8 > B0 > B0.4 > B0.2. Our results demonstrate that the integrated grain quality is optimal at 1.6 mg kg−1 B concentration in moderate B level soil. [ABSTRACT FROM AUTHOR]

The accurate and robust speed prediction of high-speed trains (HSTs) is a challenging task in the automatic train operation (ATO) because HSTs operate in an open-air situation with much noise and many uncertainties. This paper contributes to the development of robust speed prediction methods for the ATO of HSTs based on improved echo state networks (ESNs). Firstly, an adaptive temporal scale selection approach is introduced to improve the accuracy and efficiency of ESN modeling, due to the importance of proper temporal scale selection in relation to the sound prediction performance of ESNs. Also, a random weight scaling mechanism is employed to enhance the feasibility and robustness of the proposed method, as the learning ability of ESNs lies in the constrained random connection weights. Furthermore, several conditions for the stability of the closed-loop control system are given. Our experiment results demonstrate that the proposed method successfully achieves sound performance in terms of speed prediction accuracy, efficiency and robustness. [ABSTRACT FROM AUTHOR]

Background and aims: Nitrogen (N) is critical for zinc (Zn) uptake into plant roots, which promotes Zn accumulation and biofortification of grains in winter wheat (Triticum aestivum L.). However, little is known about the role of TaZIPs genes in the Zn uptake and translocation in response to N supply. This study explored a possible avenue to improve Zn uptake and translocation by adjusting N supply in winter wheat. Methods: Winter wheat (Triticum aestivum.cv Zhengmai379) was cultivated with low, medium and high N in a nutrition solution or a pot soil with or without Zn supply. Plants in hydroponic culture were harvested at 21 d after different treatments and those in the soil culture were harvested at grain filling stage, and N and Zn concentrations and accumulation, Zn translocation coefficient, and the expression of TaZIP3 and TaZIP7 in different tissues were determined. Results: When N supply was increased, Zn concentration and accumulation in shoot, Zn accumulation in whole plants, and root-to-shoot translocation of Zn were decreased in the solution without Zn supply. In the solution with Zn supply, increasing N supply increased Zn concentration in shoot, and medium N supply increased Zn accumulation in shoot and whole plants. Increasing N supply increased Zn concentration and accumulation in root, stem, leaf, glume and grain, and Zn translocation form root to stem, but decreased Zn translocation from stem to leaf, stem to glume and glume to grain under both Zn-deficient and Zn-sufficient conditions. Medium N supply up-regulated the expression of TaZIP3 and TaZIP7 in the roots of winter wheat cultured under both Zn-deficient and Zn-sufficient conditions. In Zn-deficient soil, the expression of TaZIP3 and TaZIP7 in root and glume was up-regulated but that in stem and leaf was down-regulated by increasing N supply. Medium or high N supply induced the expression of TaZIP3 and TaZIP7 in different tissues of winter wheat grown under Zn-sufficient condition. Conclusions: Adequate N supply improves the grain Zn concentration through enhancing Zn uptake and root-to-shoot translocation, which could be mediated by induced expression of TaZIP3 and TaZIP7 in roots of winter wheat. [ABSTRACT FROM AUTHOR]

Wheat (Triticum aestivum L.) has relatively high tolerance to cadmium (Cd), but the underlying mechanisms are poorly understood. Growth and physiological parameters of wheat exposed to different Cd concentrations (0, 0.5, 5 and 50 µM) were characterized. The fresh weight, leaf chlorophyll and carotenoid concentrations and photosynthesis parameters did not differ among Cd treatments, suggesting relatively high Cd tolerance in wheat. However, the soluble sugar concentrations increased with the increasing Cd concentration and the soluble protein concentrations decreased in both shoots and roots, suggesting that the Cd application promoted nitrogen metabolism over carbon metabolism. In addition, the higher concentrations of MDA, GSH and AsA and activities of antioxidant enzymes (SOD, POD, and CAT) were observed in leaves and roots in the Cd50 treatment. Our results reveal that wheat can tolerate Cd by enhancing the antioxidant enzymes activities and increasing the concentration of ascorbate and glutathione. [ABSTRACT FROM AUTHOR]