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Maize is an important feed and industrial cereal crop and is crucial for global food security. The development of drought-tolerant genotypes is a major aim of breeding programs to fight water scarcity and maintain sustainable maize production. Late embryogenesis abundant (LEA) proteins are a family of proteins related to osmotic regulation that widely exist in organisms. Here, we implemented a previously generated maize transcriptomic dataset to identify a drought-responsive gene designated ZmNHL1. Bioinformatics analysis of ZmNHL1 showed that the protein encoded by ZmNHL1 belongs to the LEA-2 protein family. Tissue specific expression analysis showed that ZmNHL1 is relatively abundant in stems and leaves, highly expressed in tassels and only slightly expressed in roots, pollens and ears. Moreover, the activity of SOD and POD of plants from three 35S::ZmNHL1 transgenic lines under either the induced drought stress conditions (by 20% PEG6000) or the natural water deficit treatment (by water withholding) were higher than that of the WT plants, while the electrolyte leakage of the 35S::ZmNHL1 transgenic plants was lower than that of the WT plants under both drought treatments. Our data further revealed that ZmNHL1 promotes maize tolerance to drought stress in 35S::ZmNHL1 transgenic plants by improving ROS scavenging and maintaining the cell membrane permeability. Overall, our data revealed that ZmNHL1 promotes maize tolerance to drought stress and contributes to provide elite germplasm resources for maize drought tolerance breeding programs.

MYB transcription factors play pivotal roles in hormone conduction signaling and abiotic stress response. In this study, 54 differentially expressed ZmMYB genes were identified and comprehensive analyses were conducted including gene’s structure, chromosomal localization, phylogenetic tree, motif prediction, cis-elements and expression patterns. The results showed that 54 genes were unevenly distributed on 10 chromosomes and classified into eleven main subgroups by phylogenetic analysis, supported by motif and exon/intron analyses. The mainly stress-related cis-elements were ABRE, ARE, MBS and DRE-core. In addition, 8 core ZmMYB genes were identified by co-expression network. qRT-PCR results showed that the 8 ZmMYB genes exhibited different expression levels under different abiotic stresses, indicating that they were responsive to various abiotic stress. These results will provide insight for further functional investigation of ZmMYB genes.

Modern information technology empowers education and infuses new vigor into educational innovation. However, current university diplomas are old-fashioned, not connected to information technology, and easy to copy. Two-dimensional code technology, widely popular in China because of its intuitive, simple, convenient, and other advantages, should be integrated into the field of education. Two-dimensional code technology is the advanced form of graphic code technology. However, through the analysis of the current situation of graphic code technology research and education applications including two-dimensional code, there are no actual cases of graphic code technology applied to graduation certificates, leaving a blank field of research. This is mainly due to the defects and limitations of the existing graphic code technology, so a new intelligent graph element technology (IGET) is proposed here. Intelligent graph element technology integrates the functional advantages of two-dimensional code and overcomes the issues of certificates being easy to forge and difficult to verify, by adding intuitive, discernible, and valuable new functions, suitable for the functional requirements of the graduation certificate. Based on intelligent graph element technology, a novel graduation certificate management system model is constructed here, and a graduation certificate is designed and implemented. Compared with the traditional graduation certificate, the graduation certificate based on intelligent graph elements has the advantages of being intuitive and readable, and having information security, a large amount of information, and intelligent anti-counterfeiting, verification, and traceability mechanisms. The application of intelligent graph element technology in the design and research of college graduation certificates opens a new window of digitization and informatization innovation for traditional college graduation certificates, and provides reference for other innovative applications of intelligent graph element technology in the field of education.

Conventional farming practices not only constrained food security due to low yield but also threatened the ecosystem by causing groundwater decline and groundwater nitrate contamination. A two׹ear field experiment was conducted at the research station of North China University of Water Resources and Electric Power, Zhengzhou. The WHCNS model was used to simulate grain yield, water and nitrogen fertilizer use efficiencies (WUE and FNUEs) of spring maize under border irrigation method, drip irrigation, and rainfed conditions. In addition, a scenario analysis was also performed on different dry and rainy seasons to assess the long-term impact of rainfall variability on spring maize from 2000–2017. The result showed that the model precisely simulated soil water content, N concentration, crop biomass accumulation, and grain yield. The maximum and minimum range of relative root mean squire error (RRMSE) values were 0.5–36.0% for soil water content, 14.0–38.0% for soil nitrate concentrations, 19.0–24.0% for crop biomass and 1.0–2.0% for grain yield, respectively under three irrigation methods. Both the index of agreement (IA) and Pearson correlation coefficient (r) values were close 1. We found the lowest grain yield from the rainfed maize, whereas the drip irrigation method increased grain yield by 14% at 40% water saving than border irrigation method for the two years with the 11% lower evaporation and maintained transpiration rate. Moreover, the drip irrigated maize had a negligible amount of drainage and runoff, which subsequently improved WUE by 27% in the first growing season and 16% in the second rotation than border irrigation. The drip irrigated maize also showed 24% higher FNUE. The reason of lower WUE and FNUEs under the border irrigation method was increased drainage amounts and N leaching rates. Furthermore, scenario analysis indicated that the dry season could result in a 30.8% yield decline as compared to rainy season.

In this study, green tea waste (GTW) was used to synthesize the iron oxide (IO) nanoparticles (IO@GTW) to facilitate the adsorption of heavy metals from wastewaters. To satisfy structural integrity needs, the synthesized IO@GTW was incorporated into a polyvinyl alcohol (PVA)/alginate polymer network to obtain PVA/alginate/IO (PAI) hydrogels. Experimental techniques of transmission electron microscopy (TEM), dynamic light scattering (DLS), X-ray diffraction (XRD), and Fourier transform infrared spectroscopy (FT-IR) were subsequently used to confirm the successful synthesis of IO nanoparticles. Scanning electron microscopy (SEM) established the porous microstructure of PAI hydrogels, while FT-IR analysis revealed the physical incorporation of IO@GTW in PAI hydrogels. The adsorption of Cu2+ and Cr6+ on PAI hydrogels was subsequently investigated. The present study was able to show that the removal ratio and adsorption capacity of the synthesized PAI hydrogels depended on the pH, initial concentration of metal ions in the solution, and contact time. The equilibrium isotherms of Cu2+ and Cr6+ adsorption were well-described using Langmuir and Freundlich isotherm models. The adsorption kinetics of Cu2+ can be modelled using the pseudo-second-order model, and the adsorption kinetics of Cr6+ can be modelled using both pseudo-first-order and intraparticle diffusion models. This study, therefore, demonstrates the functionality of integrating green tea waste in a polymeric composite to perform as an effective and green adsorbent for heavy metal removal, thus indicating the viability of its future application in wastewater treatment operations.

In recent years, the sustainable development of education has become an increasing concern, and new technology characterized by intelligence has played an important role in promoting it. However, facing the endless stream of teaching platforms, learning platforms, student management platforms and learning APPs, teachers and students are tired of coping. Meanwhile, there has been a serious lack of real information about student growth, especially in the fields of electronic graphics, and audio and video materials. At present, there is no continuous student growth system that can be used over the course of their life, which is very unfavorable to their individual development. Graphic code is a technology with the potential to solve these problems; however, the existing graphic code technology suffers from clear deficiencies in the realization of a personalized student growth system that incorporates intelligence, security and sustainability. In response to this, this paper proposes a new generation of graphic code technology, namely intelligent graph element technology (IGET). Further, a new sustainable personalized student growth system model is designed based on artificial intelligence, big data analysis and intelligent graph element technologies, and the architecture and implementation of this system platform are completed. Finally, a student growth system based on intelligent code is verified through by an analysis of the results of a questionnaire survey. The research results show that, compared with the traditional student management system, the student growth system based on an intelligent graph element code has obvious advantages in convenience, intelligence, precision, security, and sustainability.

Serine/threonine protein phosphatases play essential roles in plants. PP2C has diverse functions related to development and stress response, while little is known about the functions of PP2C genes with respect to a variety of stresses in maize. In the present study, three ZmPP2C genes, ZmPP2C55, ZmPP2C28, and ZmPP2C71, were identified. Subcellular localization demonstrated that ZmPP2C28 and ZmPP2C71 were nuclear proteins, and ZmPP2C55 was located in both the nucleus and cytoplasm. qRT–PCR analysis showed that ZmPP2C55, ZmPP2C28, and ZmPP2C71 were expressed in roots, leaves and stems, and the three genes were responsive to drought, salt, high-temperature stress and exogenous ABA treatment. To explore the function of the ZmPP2C gene, ZmPP2C55-overexpressing transgenic lines were generated. The transgenic plants exhibited higher RWC, proline content, POD and SOD activities, GSH content and GSH/GSSG ratio and lower MDA content, electrolyte leakage and GSSG content compared with WT plants under natural stress treatment when seedlings were at the three-leaf. Our results illustrated that the overexpression of ZmPP2C55 positively enhanced tolerance to drought stress.

Drought severely affects the growth and development of maize, but there is a certain degree of compensation effect after rewatering. This study intends to elaborate the response mechanism of maize at the physiological and molecular level as well as excavating potential genes with strong drought resistance and recovery ability. Physiological indexes analysis demonstrated that stomata conductance, transpiration rate, photosynthesis rate, antioxidant enzymes, and proline levels in maize were significantly altered in response to drought for 60 and 96 h and rewatering for 3 days. At 60 h, 96 h, and R3d, we detected 3095, 1941, and 5966 differentially expressed genes (DEGs) and 221, 226, and 215 differentially expressed miRNAs. Weighted correlation network analysis (WGCNA) showed that DEGs responded to maize drought and rewatering through participating in photosynthesis, proline metabolism, ABA signaling, and oxidative stress. Joint analysis of DEGs, miRNA, and target genes showed that zma-miR529, miR5072, zma-miR167e, zma-miR167f, zma-miR167j, miR397, and miR6214 were involved to regulate SBPs, MYBs, ARFs, laccases, and antioxidant enzymes, respectively. Hundreds of differentially expressed DNA methylation-related 24-nt siRNA clusters overlap with DEGs, indicating that DNA methylation is involved in responses under drought stress. These results provide new insights into the molecular mechanisms of drought tolerance, and may identify new targets for breeding drought-tolerant maize lines.

The straw returning technique is one of the important measures for soil carbon sequestration and soil organic carbon (SOC) promotion in the world. However, the patterns of straw utilization in China with various methods among regions, the effect and variability of straw returning on SOC in different areas of China remain uncertain. We conducted a meta-analysis of 446 sets of data from 95 studies in China field to explore how the environmental factors and field management affect SOC after straw returning. The results showed that straw returning to the field significantly increase SOC content by an average of 13.97% (n = 446). The SOC increased effects are more obvious under areas with mean annual precipitation (MAP) > 500 mm, temperature (MAT) > 10 °C, loam or sandy soil, or the initial SOC content

Backgrounds: Drought stress is one of the major factors that affects maize yield. ZF-HD transcription factors have been proved to play pivotal roles in the regulation of plant growth, hormone conduction signaling and abiotic stress response. However, the molecular mechanism of ZmZHD9-mediated drought tolerance is not well understood. Results: In the present study, we analyzed the functions of ZmZHD9, a member of the maize ZF-HD family. ZmZHD9 is predominantly expressed in leaves, and was induced by drought, salinity, high temperature and abscisic acid (ABA). Subcellular localization indicated that ZmZHD9 protein was localized in the nucleus. ZmZHD9-overexpressing plants showed increased tolerance to drought stress compared with wild-type plants, evaluated by higher RWC and proline content, higher SOD and POD activity, lower REL and MDA content in transgenic plants under drought stress. In addition, the expression of six stress-responsive genes were significantly higher in ZmZHD9 transgenic plants than that in wild-type plants under drought stress.Conclusion: These results demonstrate that ZmZHD9 as a stress-responsive transcription factor which plays a positive regulatory role in response to drought.

The plant-specific NAC transcription factor (TFs) plays crucial role in plant growth as well as in stress resistance. In the present study, 87 Zea mays NAC TFs were obtained from the transcriptome analysis using drought-resistant maize inbred line Y882 as experimental material under PEG stress and rewatering treatment. Comprehensive analyses were conducted including genes structure, chromosomal localization, phylogenetic tree and motif prediction, cis-elements and expression patterns. The results showed that the 87 ZmNAC genes distributed on 10 chromosomes and were categorized into 15 groups based on their conserved gene structure and motifs. Phylogenetic tree analysis was also constructed referencing to the counterparts of Arabidopsis and rice, and the stress-related cis-elements in the promoter region were also analyzed. 87 ZmNAC genes exhibited different expression levels at 3 treatment points, indicating different response to drought stress. This genome-wide analysis of 87 ZmNAC genes will provide basis for further gene function detection. ELECTRONIC SUPPLEMENTARY MATERIAL: The online version of this article (10.1007/s12298-020-00770-w) contains supplementary material, which is available to authorized users.

Virus-induced gene silencing (VIGS) is an important tool for gene function analysis in plants. In the present study, the function identification of a candidate gene named Tadhn1312 encoding Dehydrin protein obtained from the high-throughput transcriptome was carried out by VIGS. Leaves appeared the chlorotic phenotype and the transcript level of TaPDS decreased rapidly at 7 days after the inoculation by BSMV: TaPDS, which indicated that the virus had successfully infected wheat leaves and the BSMV system was efficient. The chlorophyll content of leaves with BSMV: TaPDS and BSMV: Tadhn1312 inoculation decreased at 7 days, and reached significant level compared with the control. After the inoculation by BSMV: Tadhn1312, the transcript level of Tadhn1312 was rapidly decreased at 7 days, and reached the minimum value at 21 days, indicated that Tadhn1312 had been silenced. The spike differentiation procession of wheat plants inoculated by BSMV: Tadhn1312 was late than that inoculated by BSMV: 00. The result showed that the silencing of Tadhn1312 prolonged the spike differentiation process, illustrating that Tadhn1312 gene was involved in the spike differentiation process of wheat directly or indirectly.

OSCAs are hyperosmolality-gated calcium-permeable channel proteins. In this study, two co-expression modules, which are strongly associated with maize proline content, were screened by weighted correlation network analysis, including three ZmOSCA family members. Phylogenetic and protein domain analyses revealed that 12 ZmOSCA members were classified into four classes, which all contained DUF221 domain. The promoter region contained multiple core elements responsive to abiotic stresses and hormones. Colinear analysis revealed that ZmOSCAs had diversified prior to maize divergence. Most ZmOSCAs responded positively to ABA, PEG, and NaCl treatments. ZmOSCA2.3 and ZmOSCA2.4 were up-regulated by more than 200-fold under the three stresses, and showed significant positive correlations with proline content. Yeast two-hybrid and bimolecular fluorescence complementation indicated that ZmOSCA2.3 and ZmOSCA2.4 proteins interacted with ZmEREB198. Over-expression of ZmOSCA2.4 in Arabidopsis remarkably improved drought resistance. Moreover, over-expression of ZmOSCA2.4 enhanced the expression of drought tolerance-associated genes and reduced the expression of senescence-associated genes. We also found that perhaps ZmOSCA2.4 was regulated by miR5054.The results provide a high-quality molecular resource for selecting resistant breeding, and lay a foundation for elucidating regulatory mechanism of ZmOSCA under abiotic stresses.

A field experiment was conducted to explore the effect of different sowing time and seeding rate on yield components and water use efficiency (WUE) of winter wheat by regulating the growth redundancy and physiological traits of root and shoot. Winter wheat sowing was performed on Oct.12 (T1), Oct.22 (T2), Nov.3 (T3), respectively. There were three treatments of different seeding rates, i.e. 112.5 kg hm−2 (D1), 150 kg hm−2 (D2) and 225 kg hm−2(D3) in each sowing time. The results showed that sowing time and seeding rate significantly influenced the morphological and physiological characteristics of winter wheat. Plant height, ineffective tiller number, leaf area and root biomass decreased significantly along with the delay of sowing date. Plant height, ineffective tiller number and root biomass increased significantly and leaf area decreased significantly with increasing seeding rate. Under the same seeding rate condition, T1 had the highest number of ineffective tiller, and T3 had the lowest one. Delayed sowing (T2 and T3) increased significantly root activities and leaf photosynthetic rate (Pn) in the late growing stage, and decreased significantly root respiration rate (Rroot) per unit area of wheat. In the same sowing time treatment, root activities and leaf Pn decreased significantly and Rroot increased significantly with the increase of seeding rate; however, seeding rate had no effect on root activity and leaf Pn in T3 treatment. Grain yield decreased significantly in T1 and increased significantly in T3 with the increase of seeding rate, and it was the highest in D2 and the lowest in D1 in T2 treatment. Delayed sowing lowered significantly soil water consumption of crop. Under the same sowing time condition, soil water consumption increased significantly as seeding rate increased. WUE decreased significantly with the increase of seeding rate in T1and T2 treatments. In two test years, T2D2 had highest grain yield and WUE, and T3D1 had lowest grain yield and WUE. The interaction of sowing time and seeding rate also had significant effect on soil water consumption, grain yield and WUE. It is clear that appropriate sowing time and seeding rate (T2 Treatmeat) can increase grain yield and WUE of winter wheat by regulating the growth redundancy and physiological traits of root and shoot, but excessive reduction of vegetative organs (T3 Treatmeat) can affect crop production.

Excessive water and fertilizer input in conventional farming practices not only lead to low production but also damaged the ecosystem by causing groundwater decline and groundwater nitrate contamination. The two-year field experiments were conducted at Zhengzhou of China and TandoJam of Pakistan sites, respectively. The WHCNS (soil-water-heat-carbon-nitrogen-simulator) model was used to simulate soil water dynamic, nitrogen (N) fate and maize yield under different irrigation practices, including farmer-based full flood irrigation (FI), drip irrigation (DI) and rainfed (RF) at the Zhengzhou site. Treatments of the TandoJam site were full flood irrigation (F100), moderate deficit irrigation (F75) and high deficit irrigation (F50) to meet the 100%, 75% and 50% crop evapotranspiration, respectively. Results showed that the model precisely simulated water consumption, fates of N, crop growth, and yield at both sites. In Zhengzhou site, we found the lowest grain yield in the RF system, whereas the DI increased average grain yield by 9.8%, decreased 62.5% water consumption compared to FI for the two years. Moreover, the DI had a negligible amount of drainage, runoff, and N leaching, which subsequently improved water use efficiency (WUE) up-to 24.5% and 9.1% fertilizer N use efficiency (FNUE). In TandoJam site, compared to F100, the F75 produced almost equal grain yield with 25.1% water-saving, reduced 42.5% drainage and 11.8% runoff, 57% N leaching, enhanced 4.1% WUE and 14.9% FNUE. Furthermore, results suggested that too deficit irrigation, for example, F50, could cause serious yield loss or complete crop failure, because the weather condition of the TandoJam site is very hot.

Understanding the temporal and spatial patterns of soil water extraction and their impacts on growth response of winter wheat to deficit subsurface drip irrigation (SDI) conditions is critical for managing water scarcity and stabilizing yield. A field experiment was conducted from 2016 to 2018 involving five SDI amounts: 0.25 ETc, 0.4 ETc, 0.6 ETc, 0.8 ETc, and 1.0 ETc, representing 25%, 40%, 60%, 80%, and 100% of crop evapotranspiration (ETc), respectively. The results showed that the 0.6 ETc treatment significantly increased soil water extraction from 40–80-cm and 80–140-cm from jointing to maturity as compared to the 1.0 ETc treatment. Whereas the 0.8 ETc treatment significantly increased soil water extraction from 80–140-cm deep soil from flowering to maturity in the first growing season. The crop was most water-stressed under the 0.25 ETc and 0.4 ETc treatments, thus extracted more soil water from 0–140-cm soil profile. However, both treatments exhibited minimum plant tillers, lowest leaf water content, leaf area index (LAI), photosynthetic rate (Pn), and transpiration rate (Tr) as well as grain yield. All these parameters, except for leaf water content, Pn after the flowering stage, and grain productivity, were also reduced in the 0.6 ETc treatment than the 1.0 ETc treatment. The differences between the 0.8 ETc and 1.0 ETc treatments were minor in terms of plant height, LAI, spike number, Pn and Tr, but infertile tillers were fewer in the 0.8 ETc treatment. We obtained high yield from the 0.8 ETc treatment, and the 0.6ETc treatment resulted in the highest harvest index with improved WUE than other treatments. Integrating deficit irrigation into SDI can save water in winter wheat production in water-limited regions, which can not only enhance soil water extraction from deep soil layers, but also sustained yield by stimulating crop growth. Therefore, a deficit SDI system would be used to conserve water in water-limited regions.

Drought can severely limit plant growth and production. However, few studies have investigated gene expression profiles in maize during drought/re-watering. We compared drought-treated and water-sufficient maize plants by measuring their leaf relative water content, superoxide dismutase and peroxidase activities, proline content, and leaf gas exchange parameters (photosynthetic rates, stomatal conductance, and transpiration rates). We conducted RNA sequencing analyses to elucidate gene expression profiles and identify miRNAs that might be related to drought resistance. A GO enrichment analysis showed that the common DEGs (differently expressed genes) between drought-treated and control plants were involved in response to stimulus, cellular process, metabolic process, cell part, and binding and catalytic activity. Analyses of gene expression profiles revealed that 26 of the DEGs under drought encoded 10 enzymes involved in proline synthesis, suggesting that increased proline synthesis was a key part of the drought response. We also investigated cell wall-related genes and transcription factors regulating abscisic acid-dependent and -independent pathways. The expression profiles of the miRNAs miR6214-3p, miR5072-3p, zma-miR529-5p, zma-miR167e-5p, zma-miR167f-5p, and zma-miR167j-5p and their relevant targets under drought conditions were analyzed. These results provide new insights into the molecular mechanisms of drought tolerance, and may identify new targets for breeding drought-tolerant maize lines.Abbreviationsleaf relative water content: RWC, superoxide dismutase activity: SOD, peroxidase activity: POD, proline content: Pro, photosynthetic rates: Pn, stomatal conductance: Cond, transpiration rates: Tr.; quantitative real-time polymerase chain reaction: qPCR; abscisic acid; ABA; polyethylene glycol :PEG; Principal component analysis :PCA; polyacrylamide gel electrophoresis :PAGEHighlightThe study of physiology and molecular mechanism of maize laid a theoretical foundation for drought resistance breeding under drought stress and re-watering.