Drought stress introduces growth, physiological traits and ecological stoichiometry changes in two contrasting Cunninghamia lanceolata cultivars planted in continuous-plantation soils.

BACKGROUND: The decrease in Cunninghamia lanceolata (Lamb.) production on continuously planted soil is an essential problem. In this study, two-year-old seedlings of two cultivars (a normal cultivar, NC, and a super cultivar, SC) were grown in two types of soil (not planted (NP) soil; continuously planted (CP) soil) with three watering regimes, and the interactive effects on plant growth and physiological traits were investigated in a greenhouse experiment. The water contents of the soil in the control (CK) (normal water content), medium water content (MWC) and low water content (LWC) treatments reached 75-80 %, 45-50 % and 20-25 % of the field water capacity, respectively. RESULTS: The results indicated that the CP soil had a negative effect on growth and physiological traits and that the LWC treatment caused even more severe and comprehensive negative effects. In both cultivars, the CP soil significantly decreased the height increment (HI), basal diameter increment (DI), dry matter accumulation (DMA), net photosynthetic rate (Pn), total chlorophyll content (TChl), carotenoid content (Caro) and photosynthetic nitrogen use efficiency (PNUE). Compared to the NP soil, the CP soil also decreased the proline and soluble protein contents, nitrogen use efficiency (NUE) and phosphorus use efficiency (PUE) and increased the nitrogen:phosphorus ratio in roots, stems and leaves. The LWC treatment decreased growth and photosynthesis, changed ecological stoichiometry, induced oxidative stress, promoted water use efficiency and damaged chloroplast ultrastructure. Significant increases in ascorbate peroxidase (APX), peroxidase (POD), soluble protein and proline contents were found in the LWC treatment. Compared with the NC, the SC was more tolerant to the CP soil and water stress, as indicated by the higher levels of DMA, Pn, and WUE. After exposure to the CP soil and watering regimes, the decreases in biomass accumulation and gas exchange were more pronounced. CONCLUSIONS: The combination of drought and CP soil may have detrimental effects on C. lanceolata growth, and low water content enhances the impacts of CP soil stress on C. lanceolata seedlings. The superiority of the SC over the NC is significant in Chinese fir plantation soil. Therefore, continuously planted soil can be utilized to cultivate improved varieties of C. lanceolata and maintain water capacity. This can improve their growth and physiological performance to a certain extent.

Numerical Calculation of Apparent Contact Angles on the Hierarchical Surface with Array Microstructures by Wire Electrical Discharge Machining.

It is necessary to theoretically research wettability in superhydrophobic surface fabrication. Here, a numerical calculation approach is proposed for determining the contact angle of the water droplets on array micropillars by wire electrical discharge machining (WEDM). A hierarchical model is employed for these array microstructures, including mechanical analysis for a water droplet placed on a smooth array and wettability evaluation on the morphology of the WEDM surface. On pillars, equations are listed to solve the apparent contact angle according to force balance of gravity, tension, and pressure. As for the WEDM morphology, temperature simulation and measurement are carried out, and then the effect of roughness on surface wettability is studied. Constructed formulas predict the contact angle, and then the effect of geometric dimensions is obtained. In order to verify the assumption, array micropillars with different cross-profiles are prepared using high-speed WEDM on the Al alloy surface. Through the results of contact angle determination, the numerical calculation is carried out. This theoretical prediction is beneficial for improving the fabrication of the superhydrophobic surface by WEDM.

Identification and characterization of BoPUB3: a novel interaction protein with S-locus receptor kinase in Brassica oleracea L.

Armadillo repeat containing 1 (ARC1) is phosphorylated by S-locus receptor kinase (SRK) and functions as a positive regulator in self-incompatibility response of Brassica. However, ARC1 only causes partial breakdown of the self-incompatibility response, and other SRK downstream factors may also participate in the self-incompatibility signaling pathway. In the present study, to search for SRK downstream targets, a plant U-box protein 3 (BoPUB3) was identified from the stigma of Brassica oleracea L. BoPUB3 was highly expressed in the stigma, and its expression was increased with the stigma development and reached to the highest level in the mature-stage stigma. BoPUB3, a 76.8-kDa protein with 697 amino acids, is a member of the PUB-ARM family and contains three domain characteristics of BoARC1, including a U-box N-terminal domain, a U-box motif, and a C-terminal arm repeat domain. The phylogenic tree showed that BoPUB3 was close to BoARC1. The synteny analysis revealed that B. oleracea chromosomal region containing BoPUB3 had high synteny with the Arabidopsis thaliana chromosomal region containing AtPUB3 (At3G54790). In addition, the subcellular localization analysis showed that BoPUB3 primarily localized in the plasma membrane and also in the cytoplasm. The combination of the yeast two-hybrid and in vitro binding assay showed that both BoPUB3 and BoARC1 could interact with SRK kinase domain, and SRK showed much higher level of ß-galactosidase activity in its interaction with BoPUB3 than with BoARC1. These results implied that BoPUB3 is a novel interactor with SRK, which lays a basis for further research on whether PUB3 participates in the self-incompatibility signaling pathway.

Reinterpreting the Intercalation-Conversion Mechanism of FeP Anodes in Lithium/Sodium-Ion Batteries from Evolution of the Magnetic Phase.

Batteries with intercalation-conversion-type electrodes tend to achieve high-capacity storage, but the complicated reaction process often suffers from confusing electrochemical mechanisms. Here, we reinterpreted the essential issue about the potential of the conversion reaction and whether there is an intercalation reaction in a lithium/sodium-ion battery (LIB/SIB) with the FeP anode based on the evolution of the magnetic phase. Especially, the ever-present intercalation process in a large voltage range followed by the conversion reaction with extremely low potential was confirmed in FeP LIB, while it is mainly the conversion reaction for the sodium storage mechanism in FeP SIB. The insufficient conversion reaction profoundly limits the actual capacity to the expectedly respectable value. Accordingly, a graphene oxide modification strategy was proposed to increase the reversible capacity of FeP LIB/SIB by 99% and 132%, respectively. The results facilitate the development of anode materials with a high capacity and low operating potential.

Seismic design of rectangular/square columns in SDOF systems based on their damage performance.

The quantitative relationship between the energy dissipation capacity of RC members and displacement deformation, cumulative energy dissipation and structural design parameters were established by the research group in the early stage, and then the damage index based on energy dissipation capacity and performance index limits were proposed. Based on the existing research, the seismic design method of RC square/rectangular column members for SDOF systems based on damage performance is proposed, and the method is introduced by an example. It is found that the seismic design method establishes a quantitative relationship between the structural design parameters and seismic parameters, which is convenient to guide the structural design. The increase in the ratio of transverse reinforcement can reduce the damage to RC column members, but when the ratio of transverse reinforcement exceeds a certain threshold value, the damage reduction effect is not obvious. The increase of the earthquake duration can aggravate the development of the damage to the RC column members, and the increasing effect is first fast and then slow. This seismic design method can make up for the deficiency that the duration effect is not considered in the current seismic code.

Determination of the geographical origin of Tetrastigma hemsleyanum Diels & Gilg using an electronic nose technique with multiple algorithms.

Tetrastigma hemsleyanum Diels & Gilg, an herbal medicinal plant, is planted widely in bamboo forests in southern China to promote economic benefits. Volatile compounds (VOCs) of T. hemsleyanum from different geographical regions are difficult to identify in field forests. In this study, VOCs from leaf samples of different geographical origins were analyzed using an electronic nose with 10 different sensors. Principal component analysis (PCA), partial least-squares regression (PLS), hierarchical cluster analysis (HCA), and radial basis function (RBF) neural networks were used to determine differences among different local samples. The results demonstrated that PCA achieved an accurate discrimination percentage of 91.31% for different samples and HCA separated the samples into different groups. The RBF neural network was successfully applied to predict samples with no specified localities. T. hemsleyanum samples from geographically close regions tended to group together, whereas those from distant geographical regions showed obvious differences. These results indicate that an electronic nose is an effective tool for detecting VOCs and discriminating the geographical origins of T. hemsleyanum. This study provides insights for further studies on the fast detection of VOCs from plants and effect of forests and plant herbal medicines on improving air quality.

Micro Electrochemical Machining of Array Micro-Grooves Using In-Situ Disk Electrode Fabricated by Micro-WEDM.

This paper develops an array micro-grooves manufacturing method using micro electrochemical machining (ECM) with disk electrode, which is prepared by in-situ micro wire electrical discharge machining (WEDM). This technology focuses on the difficulty of array structure manufacture in micro-electro-mechanical systems (MEMS). A micro-ECM system is built based on the micro-WEDM machine to achieve high precision processing of the array micro-grooves. Since micro-WEDM has good performance in high precision machining of the rotating structure, single and multi-edge disk electrodes can be fabricated in-situ using graphite. The as-prepared disk tool electrode is directly used for micro-electrochemical milling of the array micro-grooves without disassembling away from the device, which avoids the positioning error caused by the re-clamping of the disk electrode. With the advantages of high surface quality and no electrode loss, micro-ECM improves the manufacture performance of the micro-parts. Through wire path optimization, the shape accuracy of the disk edge is improved. After the research of the micro-ECM parameters, the process is improved, and finally, the high precision array micro-grooves are obtained. This method combines the advantages of micro-WEDM and disk electrode micro-ECM milling, and it is convenient for large-scale manufacture of array micro-structures on micro-parts and MEMS.

Multimaterial 3D Printing for Arbitrary Distribution with Nanoscale Resolution.

At the core of additive manufacturing (3D printing) is the ability to rapidly print with multiple materials for arbitrary distribution with high resolution, which can remove challenges and limits of traditional assembly and enable us to make increasingly complex objects, especially exciting meta-materials. Here we demonstrate a simple and effective strategy to achieve nano-resolution printing of multiple materials for arbitrary distribution via layer-by-layer deposition on a special deposition surface. The established physical model reveals that complex distribution on a section can be achieved by vertical deformation of simple lamination of multiple materials. The deformation is controlled by a special surface of the mold and a contour-by-contour (instead of point-by-point) printing mode is revealed in the actual process. A large-scale concentric ring array with a minimum feature size below 50 nm is printed within less than two hours, verifying the capacity of high-throughput, high-resolution and rapidity of printing. The proposed printing method opens the way towards the programming of internal compositions of object (such as functional microdevices with multiple materials).

Roll-to-Roll Manufacturing of Robust Superhydrophobic Coating on Metallic Engineering Materials.

Creating a robust superhydrophobic surface on the conventional engineering materials at mass production is of great importance for a self-cleaning, anti-icing, nonwetting surface and low flow resistance in industrial applications. Herein, we report a roll-to-roll strategy to create durable and robust superhydrophobic surfaces with designed micro-/nanoscale hierarchical structures on many conventional engineering materials by combining electrical discharge machining and coating of carbon nanoparticles, followed by oil penetration and drying. The treated surface shows good superhydrophobic properties with a static water contact angle of 170 ± 2° and slide angle of 3 ± 1°. The treated surface also exhibits good resilience and maintains the performance after being tested in various harsh conditions, including water flushing for several days, sand abrasion, scratching with sandpapers, and corrosive solution. Significantly, the superhydrophobic surfaces also show a high efficiency of self-cleaning properties even after oil contamination during applications.