Copper (Cu) is an essential metal for human body, animals and plants, and participates in various morphological, physiological and biochemical processes. Copper is a cofactor of many enzymes and plays an important role in photosynthesis, respiration and electron transport chain. It is also a structural component of defense genes. In order to provide more systematic theoretical reference for the future study of copper stress on plants, based on the adverse effects of excessive copper on physiological processes such as plant germination, growth, photosynthesis and anti-oxidation summarized in previous studies, this paper reviews the biological functions of copper, the toxicity of excessive copper to plant growth and development, the role of copper transporters and chaperone proteins, and the tolerance mechanism of plants to copper stress. The future research direction is prospected, which provides a basis for formulating effective strategies to maintain copper homeostasis.

To explore the mechanism of tobacco male sterility and search for the key causes, this paper concludes the present research status of male sterility in tobacco based on phenotype, cytology, physiology & biochemistry, molecular mechanism and so on. Firstly, we summarized that the distinguish characteristics of tobacco sterile lines and their maintainer lines in tapetum and flower organs. Secondly, we analyzed that the effects of free proline, active oxygen, enzyme and endogenous hormones on the tobacco fertility. Finally, we described in detail that the research and analysis of the association of nuclear genes, mitochondrial genes and chloroplast genes with tobacco fertility. Furthermore, it is presented that the follow-up studies combined with the high-throughput data effectively will be benefit for the systematical research of male sterility on tobacco.

Phosphorus in soil directly determines plant growth and crop yields, but phosphorus existing forms in soil are very complex, and those phosphorus forms that can be absorbed and utilized by plants account for only a small part of total phosphorus. Therefore, it is important to study the existing forms and classification methods of phosphorus in soil to improve the phosphorus use efficiency of crops, explore ways to enhance phosphorus availability, and reduce phosphorus loss. In this paper, the existing forms of phosphorus in soil, influencing factors of soil phosphorus availability and phosphorus classification methods were reviewed. The results show that the forms of phosphorus in soil consist of two major categories: inorganic phosphorus and organophosphorus, phosphorus absorbed by plants is mainly water soluble inorganic phosphorus, and other forms of phosphorus are difficult to be absorbed by plants, causing low utilization efficiency of phosphorus in soil. There are many factors that lead to low phosphorus use efficiency, mainly ions like calcium, iron and aluminum, and organic matter, pH, temperature, moisture etc. To study and improve the mechanism of the influencing factors could effectively enhance phosphorus utilization efficiency. At the same time, with the continuous improvement of phosphorus classification methods by domestic and foreign scholars, the effective forms of phosphorus have been studied more in-depth and accurately. Bowman-Cole organophosphorus classification method and Hedley’s phosphorus classification method are the two most widely used methods at present.

Low temperature is an abiotic stress that could affect plant growth and vegetation distribution. Once the environmental temperature is continuously lower than the optimal temperature for plant growth, the plant would suffer low temperature stress, including chilling injury and freezing injury. Chilling injury refers to the damage on plant caused by low temperature of zero degree or above. The cells do not freeze at this temperature, but the cold will have physiological obstacles for thermophilic plants, causing injury or death. Freezing damage refers to the phenomenon that plants are damaged or die because of the low temperature below the freezing point. Previous studies mainly focused on the regulation mechanism of low temperature stress on plants, including the process in plants from the perception of low temperature signal to the expression of functional genes, and to the resistance to low temperature stress. This article reviews the research on cold stress on plants in recent years, analyzes the research status from the aspects of signal perception, signal transduction, functional gene expression, cold-induced physiological and cellular regulatory mechanism, and discusses the prospect of the research on plant cold resistance. It will provide a theoretical basis for cultivating new cold-resistant plant germplasms.

The paper reviews the status quo of the agriculture remote sensing technology application in China, and explores its development trends and deficiencies, aiming to provide a reference frame for decision-making on agricultural policies of China. By reviewing and summarizing literatures and policies of the past and by comparing the experiences at home and abroad, the paper sums up the significance, application level, development trends of agriculture remote sensing technology application, and makes related proposals. Under the technical support of remote sensing (RS), geographic information system (GIS), global positioning system (GPS), China shows urgent demand on agriculture remote sensing technologies, which are widely applied in the country. Meanwhile, the country has made significant progress in agriculture remote sensing technology application, whose development is featured with fundamentality, integrity, and systematicness. Compared with the advanced level in the world, agriculture remote sensing technology application in China still lags behind, it is necessary to focus on basic studies, intensify the application universality of key technologies, reinforce macro-planning at national level, so as to further improve the application of agriculture remote sensing technologies and the agricultural digitization of China.

Pesticide residues, as one of the key factors affecting the quality of Chinese herbal medicines, seriously affect the efficacy of medication, human health, and the development of the Chinese herbal medicine industry. The authors briefly summarized the status of pesticide residues in Chinese herbal medicines, including the types of Chinese herbal medicines examined, the types of pesticides frequently detected, and the types of pesticide residues. The authors also sorted out the advantages and disadvantages of the main analytical detection techniques for pesticide residues in Chinese herbal medicines, and the specific applications of chromatography and chromatography-mass spectrometry in the domain of pesticide residues in Chinese herbal medicines. The causes of pesticide residues in Chinese herbal medicines, such as indiscriminate use of pesticides and incomplete registration, different degrees of contamination in the cultivation and processing, and the imperfect residue limit standards of relevant pesticides, were reviewed, and certain suggestions for improvement were given for different causes, such as building green planting bases to guarantee the quality of Chinese herbal medicines from the source, enhancing pesticide registration management norms, developing pesticide residue detection methods with wide applicability, strengthening the knowledge of growers about pesticides, and improving pesticide residue limit standards.

The aim was to establish a method for the determination of twelve flavonoid components in Scutellaria baicalensis. The HPLC method was performed on an Agilent ZORBAX SB-C18 column (4.6 mm×150 mm, 5μm) with a detection wavelength of 280 nm and a mobile phase of acetonitrile-0.1% phosphoric acid aqueous solution at a flow rate of 1.0 mL/min and a sample volume of 10 μL. The established extraction and chromatographic conditions were used for the qualitative and quantitative analysis of Scutellaria baicalensis. The linearity of the twelve flavonoids in Scutellaria baicalensis was good in the mass concentration range (r>0.98), and the average spiked recoveries of scutellarin, apigenin-7-O-β-D-glucopyranoside, carthamidin, baicalin, luteolin, chrysin-7-O-glucuronide, wogonoside, apigenin, baicalein, wogonin，chrysin and oroxylin A were 99.7214%, 92.7039%, 103.9755%, 100.5837%, 92.4819%, 93.2465%, 99.6387%, 104.3866%, 95.0767%, 95.3245%, 92.2161%, 95.3995% (RSD<5). A method for the determination of twelve flavonoid components in Scutellaria baicalensis was established, which was easy to operate, reproducible and accurate.

Agricultural and forestry waste is a valuable biomass resource. If the resource cannot be used efficiently, it will cause serious environmental pollution and even great harm to human health. Therefore, the resource utilization of agricultural and forestry wastes is the important content of controlling agricultural non-point source pollution, saving biomass resources, energy conservation and emission reduction, protecting the ecological environment, achieving the goal of peaking carbon emissions and carbon neutralization, and social and economic sustainable development. In order to promote the resource utilization of agricultural and forestry wastes, this paper summarized the progress achieved in this field at home and abroad in recent years.

In order to study the genetic basis and genetic relationship of current rice varieties in Heilongjiang Province, 47 pairs of SSR markers published in the agricultural industry standard Protocol for the Identification of Rice Varieties SSR Marker Method (NY/T 1433—2014) were used to analyze the genetic diversity among 231 rice varieties from different accumulated temperature regions in Heilongjiang Province. The results showed that a total of 136 alleles were detected form the 47 pairs of SSR markers, alleles per locus ranged from 2 to 5, the average was 2.92. Genetic diversity ranged from 0.11 to 0.79, with an average of 0.56. The polymorphic information content (PIC) was 0.11-0.76, with an average of 0.49. The value of marker index (MI) ranged from 3.18 to 18.39, with an average of 6.52. Cluster analysis divided the 231 rice varieties into 3 categories and 7 groups, and the clustering results were consistent with the results of principal component analysis. Taken together, the genetic diversity of rice varieties in Heilongjiang Province is not rich enough (the average polymorphic information content index is 0.49), and the genetic relationship among the varieties in the same accumulated temperature area is relatively close. In variety breeding, attention should be paid to the hybridization of northern and southern varieties, in order to broaden the genetic background and cultivate new environment-friendly varieties with high-quality and high-yield.

The study of seasonal frozen soil change in Shanxi Province has important application value for revealing the response of seasonal frozen soil thawing to climate change and the direct impact of land degradation caused by frozen soil change on agricultural production, irrigation and water conservancy infrastructure and road construction in the Loess Plateau under the background of climate warming. Based on the frozen soil data from meteorological observation records at 108 stations in Shanxi Province from 1981 to 2018, this paper analyzed the spatiotemporal variation characteristics of the ground freezing date, thawing date, the number of frozen days and annual maximum depth of frozen soil, and the interannual and interdecadal variation characteristics of the annual maximum frozen soil depth, and the responses of the above factors to climate warming. Results showed that soil freezing in northern Shanxi began in September, and the frozen soil subsided in May at the latest. The depth and area of frozen soil reached the maximum at the end of winter and the beginning of spring. The date of ground freezing was postponed and the date of ground thawing was earlier, and the number of frozen days was reduced accordingly to various degrees in most parts of the province from 1981 to 2018. The annual maximum depth of frozen soil gradually decreased from north to south. The annual maximum depth of frozen soil decreased in the middle and southern parts of the province, and increased in the northern part, which might be related to the warming and wetting of winter climate in north Shanxi. Under climate warming, winter precipitation and 0 cm ground temperature had complex response relationship with the annual maximum depth of frozen soil. The annual maximum depth of frozen soil was negatively correlated with 0 cm ground temperature under the background of excessive winter precipitation. The decreasing trend of the maximum frozen soil depth was a direct response to the increase of the annual average temperature, and the response of the maximum frozen soil depth to the annual average temperature was more significant than that to the annual precipitation.

This study aims at investigating the impact of different extraction methods on the properties of dissolved organic matter (DOM) derived from biochar. Biochar was used as material, DOM was extracted with various extracting agents and extraction patterns, and the carbon content and chemical composition of the extracts were analyzed. The results showed that the DOC content of alkali extract in low-temperature biochar was relatively high (15.6-40.0 g/kg), so was the DOC content of salt extract in high-temperature biochar (0.27-7.04 g/kg). The chemical composition of DOM in the acid extract remained relatively simple, showing that SUVA₂₅₄ and SUVA₂₈₀ were low. A higher proportion of hydrophilic DOM was found in the acid extract from cornstalk-derived biochar (44.6%-73.6%) compared with that in the water and alkali extracts (11.0%-53.2% and 0.30%-31.4%), respectively (P<0.05). Correspondingly, the chemical composition of DOM in the alkali extract was relatively complex, showing that SUVA₂₅₄ and SUVA₂₈₀ were high. A higher proportion of hydrophobic DOM was found in the alkali extract from cornstalk-derived biochar (68.6%-99.7%) compared with that in the acid and salt extracts (26.4%-55.4% and 0%-46.9%), respectively (P<0.05). The study indicates that extracting agents have certain significance in biochar DOM extraction, while extraction patterns exhibit a minor effect on the properties of biochar DOM. It could provide reference for selecting biochar DOM extraction method.

With the increase of global temperature, heat stress has emerged as one of the major factors affecting plant growth and development. The substantial losses caused by heat, particularly for staple crops like rice, pose a significant impact on economic benefits. In order to unravel the molecular mechanisms underlying plant response to heat stress, the adverse effects of heat stress on the morphology, physiology, biochemistry and photosynthesis have been presented. Furthermore, the three molecular mechanisms employed by plants to cope with heat stress, including signal transduction pathways, transcriptional factor regulatory networks and the expression of heat-resistance related genes have been introduced as well. Based on these insights, this review suggests that bioinformatics, genetic engineering, cell biology and molecular biology may be further employed as tools for understanding the molecular mechanisms of heat stress in plants. At last, this review offers a prospective outlook on future research directions in this field.

The causes, influencing factors and prevention and control technologies of foodstuff browning at home and abroad are summarized. According to different conditions, browning can be divided into enzymatic browning and non-enzymatic browning, while non-enzymatic browning can be further divided into Maillard reaction, caramelization, ascorbic acid oxidative decomposition and polyphenols oxidative dimerization. There are many factors affecting browning. The factors affecting enzymatic browning include substrate type and concentration, enzyme activity, oxygen, temperature and pH, etc. The factors affecting non-enzymatic browning vary with different reactions, among which temperature and pH are the most important factors. Based on the occurrence mechanism and influencing factors of browning, the prevention and control technologies of browning include physical and chemical prevention and control technologies and the combination of both. This paper points out current problems in fruit and vegetable storage and browning prevention and control technology development, such as high energy consumption, high cost and low safety. Moreover, it further suggests that the browning prevention and control technology should be mainly physical one, supplemented by necessary chemical technology treatment, and the focus should be on the excavation of new materials and new inhibitors.

microRNA (miRNA), an endogenous small non-coding RNA, regulates target genes by guiding mRNA cleavage or inhibiting translation. The role of miRNAs becomes extremely important in the regulation of plant seed development and the response to abiotic stress. In order to further identify and clarify the functions and regulatory mechanisms of miRNAs related to seed development and response to abiotic stress, the types, target genes and functions of miRNAs involved in the regulation of embryo and endosperm development in plant seed and in response to abiotic stress such as low temperature, salt and drought stress were summarized. miRNAs are highly conserved in evolution, and their expression is tissue-specific and time-specific during biological development, but they also have similarities among different plants. However, it remains to be further elucidated how regulators of miRNAs biogenesis and function are regulated during or after transcription, and how miRNAs use transcriptional cleavage and translation inhibition mechanisms to regulate their targets. Future research on these issues will not only provide new insights into plant seed development and plant response to abiotic stress, but also provide more ideas for post-transcriptional regulation of genes.

Multiple cropping is one of important farming system in China, which plays an important role in improving the comprehensive production capacity of cultivated land in China and ensuring national food security. In order to maintain the national food security, to adapt and understand the spirit of the central document,in this paper, on the basis of overview of the multiple cropping, the author introduces development status of multiple cropping in detail, which includes the improvement of sequential cropping index, diversification of regional cropping patterns, high-efficiency of input-output and technological mechanical operations, etc., and summarizes the research progress of multiple cropping, which mainly reflects in response of multi cropping cultivation to climate change, water use efficiency, utilization of research methods and high-efficient cultivation technique, etc. In short, the development of multiple cropping is the necessary way to realize the sustainable development of agriculture in China and even the world.

The harmless and reuse of agricultural waste not only turns waste biomass into treasure, but also reduces pollution to the ecological environment and improves the living environment, which is an effective way to achieve green, circular, low-carbon, efficient and sustainable development. In this article, we conducted bibliometric statistics of the relevant literature on agricultural waste resource utilization published in China and abroad from 1990 to 2022, and comprehensively analyzed the annual trend of the number of articles published in this field and the key words with the help of CiteSpace and VOSviewer bibliometric tools. Domestic research in this area started nearly 10 years earlier than overseas, the research intensity and importance of international research in this field since 2002 have been significantly higher than that of domestic research, the growth trend of the number of annual publications is also significantly higher than that of domestic research, and the gap between the number of publications at home and abroad is also widening year by year. The research hotspots in the field are not exactly the same at home and abroad. We focus more on the use of waste for the production of organic fertilizers to realize the recycling of green and low-carbon agriculture in China; the foreign countries focus more on biomass materialization and energy utilization of waste to compensate for the consumption of non-renewable resources. Based on China's basic condition of having more people and less land, China should strive to broaden the disposal methods of agricultural waste by classifying and disposing of agricultural waste raw materials and subsequently using them for substrate, feed, fertilizer, materialization and energy. And waste gas, heat and residue should be recycled in order to realize the multi-level utilization of harmless, reduced and diversified biomass resources. The results of the study provide a reference for the development of the field of agricultural waste resource utilization in China.

In order to further study the role of endotransglucosylase/hydrolases (XTHs) in the regulation of plant growth and development, this review summarized the structures and mechanism of XTH, the functions of XTH in plant leaves, roots, stems, flowers and fruits, and the XTH expression in response to plant hormone and environmental factors. Meanwhile, the authors recognized XTH as a key enzyme in cell wall remodeling, which could loosen and strengthen cell wall, and participated in cell wall degradation and synthesis. At last, several potential problems in XTH gene research field were put forward, and the future research directions were suggested.

In this paper, the composition of the ubiquitin proteasome system, the structure of monoubiquitin, polyubiquitin, and ubiquitin-like gene and the role of ubiquitin system in plant growth and development, and the function of E3 ligase in response to biotic and abiotic stress were reviewed. In view of the existing related research, it is proposed that there are few studies on the target protein itself, few reports on the HECT family of E3 ligase, and the timing site of E3 regulatory network and ubiquitination is still unclear. The future research on ubiquitin, such as strengthening the research on cloning related genes and gene interaction, strengthening the research on target protein information and E3 molecular mechanism, is expected to provide references for the research on plant ubiquitin system, the structure and function of ubiquitin genes.

Phragmites australis is a typical perennial gramineous plant with superior reproductive capacity, This study was based on the summary of the ecological habit characteristics of P. australis, the effects of water and salt on the physiological morphology of P. australis were analyzed, and the ecological function of reed in coastal wetlands was clarified from the aspects of anti-wind and wave elimination, purification of water quality and adsorption of heavy metals. And the research progress of reed breeding technology was summarized, the aim is to provide scientific basis for making full use of the application of reed community in coastal wetland vegetation restoration and ecological construction.

To elaborate the mechanism of anthocyanin biosynthesis in plants and understand the various factors affecting anthocyanin synthesis as well as their interaction, we summarize the internal and external regulatory factors and concluded the environmental factors such as light, temperature, carbohydrate and hormone. Around the anthocyanin biosynthesis pathway, the structural genes in the pathway and its upstream transcription factors are described and analyzed. This study concludes that in plants, all kinds of external and internal factors regulate structural genes through the main transcription factors, affect the biosynthesis and accumulation of anthocyanins in plants, and maintain the dynamic balance of anthocyanins in plants. This regulation includes both positive and negative regulation. In summary, metabolic pathway of anthocyanins is gradually improved, at the same time, novel structural genes and transcription factors will be evaluated and used in genetic engineering improving the characteristics of ornamental plants.

To promote the construction of a new urban-rural relationship in the digital age, this article aims to realize the integrated development of digital villages and smart cities. Based on the review of related research on the evaluation of the development level of smart cities, we used the knowledge graph method and the fuzzy set method to screen out the common evaluation indicators of smart cities, selected characteristic indicators based on the characteristics of rural areas and extended some evaluation indicators of smart cities to digital village to build a digital village evaluation index system. With the principles of science, comprehensiveness, reliability and availability, we finally constructed an evaluation index system of digital villages including development support, digital infrastructure, digital governance, digital people’s livelihood and industrial digitization. By comparing with other evaluation index systems related to digital villages, the constructed system is more comprehensiveness and scientific, which could reflect the connotation of driving the digital village development by smart city progress, and objectively indicate the degree of urban-rural integration development based on an interactive relationship between county-level cities and villages.

This paper analyzed the food security issue under the assumption of reduction of cultivated land based on China agricultural general equilibrium model (CGE). The results show that reduction of cultivated grain land could result in the fluctuation of price index of CPI, price index of GDP, price index of investment and price index of export, bring the result of investment, capital and real GDP reduction, directly effect employment, real wages, nominal wages, household disposable income, make household consumption and government consumption reduction. RMB appreciation, tariff revenue reduction, net exports contribution to GDP decreased, national macroeconomic situation deteriorated. Therefore, the red line of 1.2 billion hm2 of cultivated land must be kept to ensure national food security.

In order to screen out maize inbred lines with excellent combining ability from 80 declassified inbred lines of the United States, analyze their utilization potential and provide the basis for rational utilization, we used PH6WC and PH4CV as test varieties to explore the combining ability and comparative advantages of the 80 maize inbred lines by NCII genetic design. The results showed that the genetic basis of the 80 American inbred lines was rich and there were real differences. The materials could be divided into 33 female parent groups and 47 male parent groups. Among the 80 test materials, LH206, PHN66, NL001, 2FACC, 6M502A, 29MIBZ2, 1538, LH128, LH181, Lp215D, PHR30, LH214 and LH213 had excellent GCA effect value for yield. The TCA effect values of PH6WC×6M502A, PHW51×PH4CV, NL001×PH4CV and LH128×PH4CV in the cross combination were excellent, and their comparative advantages were relatively strong, so further test could be carried out. The NL001, 2FACC, 29MIBZ2 and 1538 were suitable for mechanized harvesting, and the GCA showed excellent performance. Also, 6M502A, NL001 and LH128 had relatively high general combining ability, and they could be used as key inbred lines.

Biogas slurry is formed by fermentation of organic substances. Because of its large quantity and inconvenient treatment, it has become one of the sources of environmental pressure. The utilization of biogas slurry in rice production not only alleviates the pressure on environmental protection, but also improves rice yield and soil quality. It is an effective way for the resource utilization of biogas slurry. Biogas slurry is rich in nutrient elements and microbial secretions, which can provide all kinds of vitamins, auxin and amino acids required by rice. Biogas slurry has the functions of promoting rice growth and controlling rice diseases and insect pests. In seed soaking and fertilization, the use of biogas slurry instead of chemical agents can improve the drug effect and reduce the pollution level, but the application rate varies according to the composition of biogas slurry in different places. By summarizing and analyzing the rational utilization of biogas slurry resources, it is found that biogas slurry can not only improve rice yield and economic benefits, but also reduce chemical pollution, improve soil quality and drive the sustainable development of agriculture, which is of great significance to build the balance of agricultural ecological cycle.

Under the background of cultivated land resource shortage and an increasing contradiction between human and land in east China, it is urgent to increase cultivated land to ensure a ‘balance of occupation and compensation’. Coastal saline-alkali land, as a potential land reserve resource, has strategic and practical significance by its rational development and utilization to alleviate the pressure of land resource shortage, improve agricultural water resource utilization efficiency and ecosystem stability. This paper introduced the current situation and main characteristics of coastal saline-alkali land resources, and summarized the recent research progress and existing problems of coastal saline-alkali land improvement and utilization from the physical, chemical, hydraulic engineering and biological aspects, and put forward the research prospect of coastal saline-alkali land in the future from biophysical process, obstacle reduction, soil fertility improvement and nutrient expansion, development and application of new materials, soil carbon sequestration, and comprehensive management and remediation, aiming to provide new ideas, new technologies and theoretical support for coastal saline-alkali soil improvement under the background of ecological civilization in the new era.

To identify magnesium transporter (MGT) gene in tobacco genome and explore the mechanism of magnesium ion transport by MGT in tobacco plant, seven NtMGTs with conservative Gly-Met-Asn tripeptide motifs were identified from tobacco genome by homologous sequence alignment using the magnesium transporter family genes in rice and Arabidopsis genomes as reference sequences. The results showed that the expression of NtMGTs was tissue-specific and light-induced under different magnesium supply levels and light intensities. The expression of NtMGT1 in roots and NtMGT2, NtMGT4 and NtMGT5 in leaves of tobacco plants increased under strong light intensity. With the increase of magnesium supply, the expression of NtMGT1 gene in the root system increased, which was consistent with the change trend of magnesium content in the root system, suggesting that NtMGT1 gene mainly mediated the absorption of magnesium in the root system of tobacco plant. The expression levels of NtMGT2, NtMGT4 and NtMGT5 genes in leaves increased first and then decreased, indicating that the three genes belonged to a high affinity magnesium ion transport system. These results implied that under the stress of high temperature and strong light intensity, appropriate magnesium supply could increase the expression of NtMGT1 in the root part of tobacco plants, promote the absorption of magnesium ion by the root system, enhance the gene expression of NtMGT2, NtMGT4 and NtMGT5 in shoot part of tobacco plants, promote the transport of magnesium ion, and ensure the normal growth and development of tobacco plants. The results of this study can provide theoretical guidance for reasonable application of magnesium in tobacco production.

Based on the daily meteorological data and the drought disaster data of 156 stations in Sichuan Province during 1991-2013, the classification standard of the actual drought disasters was established with the method of grey correlation. The applicability of MCI in Sichuan Province was analyzed, and which was revised by using the method of projection pursuit. The results showed that the grey correlation degree of selecting three indexes of crop disaster area, social disaster population and direct economic loss could well describe the comprehensive loss of drought disaster. The applicability analysis showed that the accuracy rate of drought grade assessment based on MCI was generally low, of which the special drought occurred 21 times, and the MCI evaluation result reached 115. The inaccurate assessment of drought levels might be related to the gradual improvement of irrigation and water capacity in Sichuan province. Based on the reference sequence of the disaster grey correlation degree, the influence of each component of MCI on the actual drought was revealed by the projection pursuit method, and the optimal projection direction was found, and the revised coefficient of MCI indexes were established. Compared with MCI, the revised MCInew had significantly improved the evaluation ability of drought grade, and the accuracy of drought assessment increased from 16.5% to 62.5%. A case study also indicated that MCInew was more consistent with the actual drought occurrence and development.

The substitution of chemical fertilizers by organic fertilizers is an effective strategy to reduce the amount and increase the efficiency of chemical fertilizer. It also significantly stimulates crop yield and soil fertility. However, it is worth noting that the substitution of chemical fertilizers by organic fertilizers could contribute to greenhouse gas emissions and pollution loading in soil environment. This paper reviewed the effects of organic fertilizer application on crop quality, soil amelioration, greenhouse gas emissions and agricultural non-point source pollution. Besides, we summarized current research of organic fertilizer application and put forward proposals for further studying the organic fertilizer application. Firstly, constantly optimizing the fermentation process to improve the quality of organic fertilizer is of overarching importance. Secondly, it is suggested to strengthen the quality trait evaluation in assessing the application effect of organic fertilizer, and take full advantage of long-term positioning observation and modern monitoring means to improve the soil fertility monitoring level and accomplish the comprehensive environmental effect evaluation. These suggestions aim at providing guidance for rational and efficient application of organic fertilizers, and for sustainable utilization of soil and water resources.

To promote the study of CO in plant physiology and biochemistry, we summarize CO biosynthesis way, the physiological function regulation of CO in plant, and the interaction between CO and other signaling molecules. It is concluded that there are few studies on the role and mechanism of CO during plant biotic stress. Therefore, the study of CO in this field will become the focus in the future.

This review aims to provide theoretical references for model selection of crop water consumption and carbon-water exchange. The response of stomatal conductance to single and comprehensive environmental factors is summarized. The existing stomatal conductance models are classified and compared, including the empirical models constructed and improved based on Jarvis model, the semi-empirical models constructed and improved based on BWB model, the models constructed and improved based on ABA control and the models constructed and improved based on the guard cell swell control theory. The application of stomatal conductance model in crop water use research is also reviewed. The multi-scale joint mechanism model establishment with the entry point of the quantitative relationship between leaf stomatal conductance and canopy conductance will be the hotspots of future crop water consumption scale expansion research.

Understanding the evolution characteristics of major agronomic characters of main planting wheat varieties can provide a basis for new variety breeding and cultivation innovation. 50 main planting wheat varieties of different years in Shandong Province were used as materials, the evolution characteristics of agronomic characters and economic coefficient, and their correlation were analyzed. The results showed that, the plant height presented an extremely significant decreasing trend with the time. Every cultivar alternation decreased the plant height by 6.29 cm on average. The 1000-seed weight showed an extremely significant increasing trend, every cultivar alternation increased 1000-seed weight by 1.26 g on average. The economic yield and biological yield per stem decreased first and then increased, and they showed an extremely significant positive correlation. The economic coefficient increased significantly, and every cultivar alternation increased the economic coefficient by 24.33% on average. There was no significant change trend in spike length, kernel number per spike, total spikelet number, and the number of fertile spikelet in different years. The trend of economic yield and biological yield per stem was different from the trend of grain yield, indicating that the coordination between population yield and individual yield was an important direction to improve grain yield of wheat.

The alien invasion is a far-reaching global issue, which has a major impact on the ecosystem, environment, health, society and economic development of countries. Especially in recent years, with the acceleration of global warming and global trade liberalization, the species and amounts of invasive alien species have shown a rapid growth trend, leading to an increasingly serious threat. Without effective prevention and countermeasures, the alien invasion may lead to “bioterrorism”. This paper takes Spodoptera frugiperda which is a major pest invading China in a large scale in FAO global warnings in January 2019, as an example, analyzes the impact of invading organisms on China’s economy, ecology and society, and illustrates the possible invasion pathways of alien organisms, and dissects the challenges of prevention countermeasures of alien biological invasion in China in the current era, and also proposes a series of comprehensive prevention and control measures according to the invasion characteristics and impacts of invading organisms, including improving the management mechanism of “unified supervision, division of labor and responsibility”, accelerating the legislation of invasive alien species, completing the well-structured and scientific management system, establishing the law and monitoring system, strengthening the basic research of invasive alien species and the establishment of prevention and control networks, and deepening the science popularization and education.

The purpose of this study is to analyze the adaptability of a new rice variety ‘Yulong 7’ in the cold region, in order to provide reference for the adaptive breeding of rice varieties in the cold region. The rice variety ‘Yulong 7’ was used as material. The growth days, accumulated temperature and yield of hectare were investigated and analyzed in Heilongjiang Province, the Inner Mongolia Autonomous Region and Hubei Province. The results show that ‘Yulong 7’ could achieve not only good production in the first accumulative temperate zone of Heilongjiang Province, but also good introduction and identification results in the lower accumulative temperate zone of Heilongjiang Province, the Inner Mongolia Autonomous Region and Hubei Province, and it could be used in production in a certain range of area. Further analysis show that the strong adaptability of ‘Yulong 7’ comes from its rich genetic basis, as well as more suitable selection and identification methods. The adaptability of ‘Yulong 7’ reveals that only using the main cultivar suitable for local ecological conditions as the core germplasm and adding new gene sources can improve the adaptability and expand the suitable area of rice varieties.

Waterlogging stress is an important factor that affects the distribution, growth and development of plants. The research on plant waterlogging tolerance is critical to improving plant tolerance in order to cope with the increasingly severe extreme weather and the large-scale production management. In order to carry out researches on plant waterlogging tolerance and explore the regulation mechanism of different plants in response to waterlogging stress, we summarized the effects of waterlogging stress on plant growth, the regulation mechanism of plant in response to waterlogging stress, and analyzed the effects of waterlogging stress on plant phenotypic traits, biomass, photosynthesis, reactive oxygen species accumulation, sugar content as well as biological membrane in detail. In addition, the regulation mechanism of ethylene signal molecule, reactive oxygen species scavenging mechanism, osmotic regulation, morphological regulation, molecular and metabolic regulation of plant in response to waterlogging stress were also analyzed. Finally, it is proposed that further in-depth study should be focus on the development of exogenous regulatory substances to improve plant waterlogging tolerance.

Iron (Fe) is the earliest discovered and most abundant essential microelement in plants, which is involved in many physiological processes and metabolic pathways, Fe deficiency will seriously affect the growth, development, yield and quality of plants. Fe in plant-derived food is the main source for animal and human to obtain Fe, and insufficient Fe uptake can damage their health. In order to fully understand the metabolic physiology of Fe in plants, and promote the cultivation of iron-rich plants and the development of iron-rich food, in this review, the contents, forms and proportions of Fe in soil and plants were summarized, the distribution and function of Fe in plants were concluded, the different efficient absorption strategies of plants in small amount of soluble Fe environment were compared, and the regulation mechanisms of Fe transport in cells and long-distance in plants were analyzed. Based on the above, some research prospects were discussed in view of the previous research, it is suggested that more attention should be paid to the differences and molecular mechanisms of Fe metabolic pathways among different plant species, the Nramp family genes regulating approach of the docytotic mechanism of Fe deficiency in plants, the oxidation precipitation and reduction release mechanisms of ferritin (Fer) in the plastids, and the biofortification measures for increasing Fe content and bioavailability in plants.

Drought is one of the most important abiotic stresses affecting the growth and yield of crops. The risk of crops suffering from drought stress is increasing under climate change. In order to cope with drought, crops show a series of resistance mechanisms, including the changes of morphological characteristics, and physiological and biochemical characteristics (antioxidant enzyme, osmotic regulation substances, and endogenous hormone), which play an important role in improving the resistance of crops under drought conditions. This paper summarized the response mechanism of crops to drought stress and introduced the measures to improve the drought resistance ability of crops, including: (1) selecting drought-resistance cultivars to promote the absorption of deep soil water; (2) soil mulching, which could reduce soil evaporation and increase soil water content; (3) water-saving irrigation techniques, such as micro-sprinkler irrigation and drip irrigation, which could precisely control the irrigation application and increase irrigation frequency; in addition, partial root-zone irrigation could reduce luxurious transpiration and soil evaporation by regulating stomatal closure; (4) anti-transpirants, which could inhibit excessive transpiration of water by forming ultrathin transparent protective film on the surface of crop branches and leaves; (5) plant growth regulators, which could enhance crop drought resistance by regulating plant physiological metabolism; (6) nano-fertilizers, which could promote plant growth and development by changing physiological and biochemical reactions of crops and enhance drought resistance of crops; (7) biochar, which is beneficial to soil aeration and water retention, and could improve soil physical properties and soil water retention capacity. In order to provide a theoretical basis and technical reference for coping with drought stress, this paper systematically discussed the action mechanism, application prospect and existing problems of the above 7 measures.

Leguminosae, as important food and cash crops, have been widely valued. Rhizobia are gram-negative bacilli which are ubiquitous in soil, and can form symbiotic nitrogen fixation system with legume plants. Rhizobium can not only increase the yield of plants, but also have no effect on the surrounding ecological environment. The symbiotic system of Rhizobium and leguminous plants has the highest biological nitrogen fixation efficiency, accounting for more than 65% of the total biological nitrogen fixation. The in-depth study of the symbiotic nitrogen fixation system is beneficial to the sustainable development of China’s agriculture. In recent years, more and more scholars have been involved in the classification, identification and application of Rhizobium. In this paper, the classification, morphological level, physiological and biochemical level, cell components, nucleic acid molecular level identification and application of Rhizobium are reviewed, which could provide references for the practical application of Rhizobium.

To evaluate the nutritional quality of onion (Allium cepa) varieties from different sources and screen germplasms rich in nutrients, four nutritional quality parameters including compactness, dry matter content, soluble solid content and pyruvic acid content of 30 onion varieties were determined. A comprehensive evaluation on nutritional quality of onion was conducted with membership function from the fuzzy math and correlation analysis. The results showed that there were some differences of compactness, dry matter content, soluble solid content and pyruvic acid content in the 30 onion materials. The variation coefficient of compactness was the smallest, while that of pyruvic acid content was the largest. In addition, this study found that the dry matter content was extremely significantly correlated with soluble solids content, and significantly correlated with pyruvic acid content. Among the 30 onion materials, ‘Sterile line A1’ has the best comprehensive nutritional quality, which can provide the material foundation for onion quality breeding.

With the rapid changes of global climate, people expect to change traditional agricultural production models and establish a sustainable low-carbon and green agricultural production system. The income from grain crop cultivation in China is not enough. Young people are unwilling to engage in agricultural production, and the phenomenon of abandoned farmland is becoming increasingly serious. Most of the traditional crops are annual crops, and large amount of chemical fertilizers and pesticides are required in crop production, which has brought serious environmental and ecological problems. In addition, annual crops that have been artificially domestication for a long time generally have weak adaptability to environmental changes which leads to increasingly difficult to adapt to complex climate changes. Perennial crops have a longer life cycle and can grow continuously for many years. Compared with annual crops, perennial crops have higher natural resource utilization efficiency, less labor input, and stronger environmental adaptability. Moreover, the well-developed root systems of perennial crops can not only reduce soil erosion but also reduce the carbon elements transfer from the soil to the atmosphere, which is beneficial for retaining more carbon in soil and developing low-carbon green agriculture. Therefore, developing perennial crops is currently one of the important ways to achieve sustainable agricultural development, but there are still some challenges in the breeding of perennial crops. However, the emergence and development of new technologies have greatly accelerated the domestication process of perennial crops, and improve their agronomic traits while maintain their growth characteristics related to perenniality.

In order to remove the inherent complex resistance structure of lignocellulose and achieve efficient utilization of lignocellulose, new lignocellulosic pretreatment technologies have been improved continuously. As green solvents, Deep Eutectic Solvents (DESs) have the advantages of low cost, simple preparation, thermal stability, and designability. They have great application potential in promoting the pretreatment of lignocellulose and enzymatic hydrolysis, and have received widespread attention. Based on the analysis and summary of the research status and achievements at home and abroad, the research progress of synthesis and properties of DESs, pretreatment mechanism, enzymatic hydrolysis, and bioethanol conversion were discussed. It was pointed out that different hydrogen bond donors and different pre-treatment conditions had a significant impact on the lignin removal rate and glucose yield. It was believed that pretreatment of lignocellulose with DESs could greatly improve the saccharification rate. Prospects for DESs pretreatment mechanism, recycling, and process parameter optimization were proposed.