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.

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.

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.

Panax notoginseng (Burk.) F.H. Chen is a perennial herbaceous medicinal plant of ginseng in Acanthopanax family. The study aims to isolate endophytic fungus strains which can produce the same or similar biological active substances as the host plant from the medicinal plant. P. notoginseng was used as material. The endophytic fungi strains of P. notoginseng was isolated and purified, and then the endophytic fungi strains were identified based on the traditional morphological characteristics and ITS sequence. A total of 24 strains of endophytic fungi were isolated from cultivated P. notoginseng, and they were identified as 12 genera (species). The types and numbers of endophytic fungi in different organs and tissues of cultivated P. notoginseng were quite different, the roots and leaves had the most, and the stems had less. Among them, 11 species and 6 genera were isolated from leaves, 1 species and 1 genus from stems, 12 species and 5 genera from roots. The statistical results showed that Penicillium commune and Colletotrichum gloeosporioides were the dominant species isolated from leaves, accounting for 27.28% of the isolates from leaves; the dominant strains isolated from the fibrous roots were Chaetomidium arxii, accounting for 72.73% of the isolated root strains. The cultivated P. notoginseng endophytic fungi have rich biodiversity, thus the experimental results could provide a material basis and experimental parameters for further exploring the relationship between cultivated P. notoginseng endophytic fungi and physiological active substances.

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 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.

Pesticides play an important role in ensuring agricultural production, increasing grain yield and improving farmers’ living standards. In the process of pesticide control of pests and diseases, the active ingredients are easily degraded or lost due to the unstable physicochemical properties of the pesticides’ active ingredients and the improper application process. The utilization rate of conventional pesticide formulations is only about 20%. At the same time, there are problems such as fast release rate of active ingredients, short duration of pesticide effect and great influence of environmental conditions. Controlled release nano-pesticide formulation is a hot spot in the research of pesticide formulations. Based on the nano-dispersion preparation technology and the slow and controlled release characteristics of pesticide carriers, the serious loss of active ingredients of pesticide can be solved by combining nanotechnology with pesticide characteristics, control target, application environment and application methods, so as to improve the effective utilization rate of pesticide formulations. The active ingredients can be released continuously and stably in a specific time and space according to the requirements of pest control dose, which has met the requirements of pest control economically, safely and effectively. In this study, the research progress of nano-biomaterials in controlled release nano-pesticide formulation was reviewed, and the application prospect of controlled release nano-pesticide formulation was discussed.

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.

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.

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.

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.

Lignan is considered one of the most important bio-active components in flaxseed, and has attracted attention in recent years because of the efficacies of anti-cancer, antioxidation, anti-inflammation, diabetes prevention and cardiovascular system protection. In order to make a better understanding of the exploitation and utilization of flaxseed lignan, based on the domestic and foreign literature reviews, this article mainly reviewed the research progress on the extraction technology and biological activity application of flaxseed lignan. The effective extraction of lignan from flaxseed is the basis of bioactivity research. Different extraction processes can not only cause the difference in the extraction rate of lignan, but also affect its biological activity. This article summarizes some commonly used extraction methods for flaxseed lignan, including organic solvent extraction, subcritical water extraction and microbial fermentation. At the same time, the application of bioactivities is summed up and the research progress of lignan in the pharmaceutical field is emphasized. This article proposes prospects for the future research direction of flaxseed lignan, aiming to provide theoretical basis for the in-depth research, development and application of flaxseed lignan in the fields of medical industry and health industry.

The purpose of this experiment is to ensure the quality safety of brown rice, and reduce the bioavailability of soil Cd and the content of Cd in brown rice. In this study, four biochar-based conditioners were used as materials to evaluate their effects on reducing Cd bioavailability in soil and inhibiting Cd absorption, transportation and accumulation in rice plants in field. The results showed that after applying the four biochar-based conditioners (biochar+zeolite BZ, biochar+zeolite+organic fertilizer BZM, biochar+iron powder BFe, biochar+calcium magnesium phosphate fertilizer BP), the yield of both spring and autumn brown rice increased by 4.41%-21.18%, of which BZM and BP treatments were better and increased the yield of spring rice more significantly. The sum of Cd bioaccumulation factors (BCF) in autumn rice was significantly higher than that in spring rice (1.07-3.75 times). The Cd content of brown rice could be reduced to 0.03-0.23 mg/kg by applying the four biochar-based conditioners. Except the Cd content of autumn brown rice under BZ treatment, the Cd content of brown rice under all the other treatments could conform to the limit of the National Standard for Food Safety. BP was the most effective conditioner in reducing Cd content in brown rice and increasing rice yield. The results indicated that biochar-based conditioners had a certain value for the remediation of Cd-polluted paddy soil, and BP had more potential value in neutral or weakly alkaline soil.

The purpose of the study is to grasp the occurrence and development of the invasive weed Solidago canadensis in Yunnan Province, and put forward its prevention and control strategies. From May 2020 to May 2022, the invasion and distribution of Solidago canadensis in Yunnan were analyzed through field visit and investigation. The results show that the invasive weed Solidago canadensis is still in scattered occurrence in Yunnan, and there are invasions of farmland in some areas, and Solidago canadensis in these occurrence points are mainly introduced intentionally or spread unintentionally. Solidago canadensis has been found in many areas in Yunnan, and has a tendency of spreading. It is necessary to strengthen its control and timely prevention.

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.

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.

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.

To prevent and control the stem base rot and develop botanical fungicide resources, the growth rate method was used to determine the inhibitory effect of 15 kinds of Chinese herbal medicine extracts, such as Eugenia aromatica, on passion fruit stem base rot pathogen Fusarium oxysporum. According to the indoor toxicity test results, the 15 kinds of Chinese herbal medicine extracts had inhibitory effect degree from high to low as: Eugenia aromatica> Rhizoma ligustici> Alpinia officinarum> Magnolia officinalis> Coptis chinensis> Aucklandia lappa> Angelica sinensis> Raphanus sativus> Scutellaria baicalensis> Asarum sieboldii> Artemisia argyi> Isatis indigotica> Stemona japonica> Polygonatum sibiricun> Kochia scoparia, among which Eugenia aromatica, Rhizoma ligustici and Alpinia officinarum extracts had the best and stable antibacterial effects. When the inhibitory concentration of the above three extracts was 20, 80 and 80 mg/mL respectively, the inhibition rate could reach 100%. The virulence regression equation analysis showed that the EC₅₀ of Eugenia aromatica, Rhizoma ligustici and Alpinia officinarum extracts to the tested strains was 1.46, 1.66 and 1.81 mg/mL, respectively.

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.

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.

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.

The purpose is to provide theoretical reference and data support for optimizing the allocation of land resources and promoting the sustainable development of regional ecology, society and economy. Based on the construction of the evaluation index system of land use benefit, using the models of coupling coordination degree, relative development degree and obstacle degree, the spatial-temporal evolution characteristics and major influencing factors of the coupling coordination degree of land use ecology-society-economy system in 17 cities of the Shandong Province were explored. The results are as follows. Land use ecology-society-economy system of Shandong was in the primary coordination state of running-in stage and showed a continuous rising trend in 2008-2017. The coupling coordination degree increased steadily from 0.54 to 0.70, and its annual average was 0.63. The equilibrium level of coupling coordination degree among cities was gradually improved in 2008-2017. Its variation coefficient of coupling coordination degree decreased from 0.126 to 0.072, but the coupling coordination degree of land use ecology-society-economy system in different cities still showed an obvious gradient distribution difference from the east to the west of the province. There was a significant difference in the relative development degree among the ecological, social and economic subsystems of land use in different cities. The southern sides of central Shandong and its northern area, together with Weihai City, had constituted an obvious half-circle ecological lag region by 2017. Social and economic barriers affecting the coupling coordinated development of land use ecology, society and economy were dominant throughout, but the ecological impact increased since 2013. During the study period, the coupling coordination level of land use ecology-society-economy system in different cities in Shandong was continuously improved, but the differences among different regions were still obvious, and there was still more space for improvement. Therefore, it is suggested that different cities should consider the main obstacle factors of their own and implement differentiated development strategies according to local conditions.

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.

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.

The growth rhythm and genetic variation of the cutting clones from the F₁ hybrid of poplar were investigated to provide a basis for poplar genetic improvement and high-quality germplasm resources mining. Using 30 F₁ hybrids obtained by the controlled pollination hybridization experiment with poplar ‘I-69’ as the female parent and poplar ‘I-63’ as male parent and the two parents as the research objects, we carried out a field cutting experiment to analyze the growth process and genetic variation of the seedling height and ground diameter of the experimental materials at seedling stage. Results showed that these two growth traits of the 1-year-old cuttings from the F₁ hybrid of poplar were in line with the ‘S’ curve, and the Logistic growth equation could fit the dynamic growth rhythm well. The seedling height and ground diameter of different clones were significantly different (P<0.01), indicating obvious super-parental advantage and significant maternal parent effect. The repeatability, variation range, phenotypic variation coefficient, and the genetic variation coefficient of the two growth traits were 0.88 and 0.72, 125.11% and 108.94%, 23.67% and 19.97%, and 40.37% and 25.98%, respectively. The repeatability, phenotypic variation coefficient, and genetic variation coefficient of the two growth traits increased first and then decreased, while the genetic variance, environmental variance and phenotypic variance basically increased with growing months, and the contribution rate of genetic variance effect to phenotypic variance increased month by month. Based on the cluster analysis using seedling height and ground diameter as evaluation indexes, five clones with good growth performance traits were selected. The average seedling height and ground diameter of the five selected clones were 3.10 m and 19.92 mm, and the genetic gains were 12.48%-41.96% and 10.52%-21.83%, respectively. The five selected clones could be used as materials for forest production and poplar variety improvement.

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.

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.

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.

The grain aphid Sitobion miscanthi (Takahashi), considered as S. avenae (Fab.) in China, is one of the most widely distributed aphid species which needs chemical control annually in northern China at wheat grain filling stage. The spatial-temporal population dynamics of the grain aphid is affected by geographical area, meteorological factors, natural enemies, agricultural practices, biodiversity, and resistance characteristics of wheat varieties to aphid at different growth stages in field. In general years, the dynamics of aphid population develop with the wheat growing and temperature rise in field. The aphid number has sporadic occurrence at the jointing stage of wheat seedling and cluster occurrence at booting stage, increases rapidly after head sprouting, and reaches the peak at mid-late stage of grain filling, and decreases sharply at milking stage. The aphid spatial distribution pattern follows random distribution - contagious distribution - aggregated distribution (mosaic distribution) - uniform distribution - aggregated distribution (mosaic distribution)- disappearance. The wheat grain number is affected weakly by aphids before wheat head sprouting because the population of aphids is very small in field. But the 1000-grain weight is significantly affected by the aphid as its population increases rapidly during grain filling stage in field. In this paper, an ecological control strategy is proposed for grain aphid. We suggest that the dynamic control index of this pest should be established according to the resistance/tolerance characteristics of wheat varieties to aphid during different growth stages. The priority should be given to the biological control before wheat head sprouting, and the dynamic control index should be strict; the chemical control should be carried out after head sprouting, and the dynamic control index could be loosened. The utilization of plant protection UAV combined with artificial intelligence is also suggested to automatically discover the occurrence center of aphid and other pests/diseases, and to spray pesticides precisely on the occurrence center in wheat field simultaneously.

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.

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.

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.

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.

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.

Establishing a feasible disinfection system for obtaining the germfree mature lotus (Nelumbo) embryos as explants and understanding the differences of in vitro growth of lotus from different provenances is the basis for material selection and evaluation method to construct an efficient in vitro culture and genetic transformation system. Plant preservative mixture (PPM) at different concentrations was used in the pre-culture stage to develop a suitable disinfection system of lotus seeds and a method of acquiring the germ-free lotus embryos. Through this sterilization approach, the in vitro cultured seedlings of lotus from 9 worldwide provenances were successfully obtained. Based on the morphological indexes at different culture periods, the membership function method was used to evaluate the growth differences under the in vitro culture conditions. The results showed that the ideal disinfection system for lotus seeds was 75% alcohol 30 s + 2% PPM 2 h + 0.05% PPM 3-5 d soaking during germination. The in vitro growth differences of the seedlings from the tested lotuses of 8 provenances were mainly observed in the later culture stage, such as the number of leaves, the length and thickness of rhizomes, the number of roots and lateral shoots. The seedlings of lotus from Vietnam and Thailand had the highest growth potential and higher reproduction rate under the same culture conditions. The pre-culture method by soaking lotus seeds with PPM to successfully obtain germ-free lotus embryos has solved the technique problem in disinfecting lotus seeds in the past. The in vitro clones of lotus embryos from the tropical or subtropical regions in both Vietnam and Thailand have stronger growth capacity and therefore are the materials more ideal for establishing regeneration and genetic transformation system of Nelumbo.

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.

It is important to explore the appearance characteristics of flue-cured tobacco of woody and honey-sweetness flavor type for excavating its application value. Based on the C2F samples of flue-cured tobacco from 6 core planting areas in the northeast plain ecological region, several classical and geostatistical methods were used to describe and evaluate the appearance characteristics, differences and spatial characteristics were analyzed, and the relationship between the appearance characteristics and the intrinsic quality of tobacco leaves was discussed. The results showed that: (1) obvious wax texture, slightly dense structure, orange or light yellow color and slightly weak color intensity (plumpness) were the relatively distinct appearance identification characteristics of flue-cured tobacco. (2) The optimal model of background color and leaf color difference between front and back was a linear model, and the indexes showed pure nugget effect and weak spatial autocorrelation. The optimal model of thickness, leaf body difference between tip and base, luster and maturity was an exponential model. The optimal model of wax texture, flexibility, leaf structure, and body and color intensity was a spherical model. The optimal model of leaf surface tissue, color depth, color and oil was a Gaussian model. The leaf surface tissue and color intensity showed moderate spatial autocorrelation, and the remaining 11 indexes showed strong spatial autocorrelation, with their nugget coefficients from 0.10% to 22.86%. The distribution of leaf structure was relatively uniform, and the flexibility, luster, color, maturity and color intensity were generally high in the middle and low in the periphery. The remaining 9 indexes generally showed a gradual upward trend from the northeast to the southwest in the whole or sub region. (3) Generally, the thicker the thickness, and the lower the maturity, the higher the starch; the smaller the leaf color difference between front and back, the lower the chlorine; the smaller the leaf body difference between tip and base, the higher the potassium/chlorine and reducing sugar/total sugar; the lighter the color, the lower the nicotine. Generally, the more the oil, the more obvious the honey-sweetness and green scents, and the better the aroma quality in the sensory evaluation; the looser the leaf structure, the more obvious the woody scent; the thicker the thickness, the more abundant the aroma and the better the aroma permeability, and the greater the smoking strength. The study firstly clarified the main appearance indexes and corresponding relationships for identifying the origin and intrinsic quality of woody and honey-sweetness flavor type flue-cured tobacco, and preliminarily explored the spatial variation and distribution characteristics of indexes. The results could provide intuitive reference for targeted development and precise purchase of feature tobacco leaves.

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.

Based on the related data of the Minqin Meteorological Administration, the Water Affairs Bureau, the Forestry Administration and field investigation, the ecology of Minqin oasis were analyzed since the comprehensive treatment of the Shiyang River Basin. The results show that: (1) the dust weather and atmospheric dust-fall decreased obviously; (2) the moving velocity of sand dunes tend to be gentle, advance and retreat speed of the desert decreases, most of the sand dunes and deserts on the edge of the oasis have been effectively controlled; (3) the surface water quantity is increasing annually, the amount of groundwater exploitation and the decline rate of groundwater level decreases obviously, the groundwater level of the key governance area has a certain recovery; (4) the artificial afforestation and the sand pressing area are increasing annually, the vegetation coverage and the forest coverage rate are improved obviously. The ecological deterioration trend of Minqin oasis has been curbed after the comprehensive treatment, and partial region are improved and restored. The comprehensive treatment of Shiyang River Basin achieved remarkable results.