Pollen is one of the main forms of plant germplasm and it contains all genotypes of the species. Research on the preservation of plant pollen is of great significance for improving the conservation method of germplasm resources and accelerating the breeding process. In order to meet the needs of germplasm resources conservation and hybrid breeding, the authors expounded the effects of pollen types, genotypes, chemical components and environmental factors on plant pollen viability, and summarized main methods of plant pollen collection and viability measurement as well as the main preservation methods of plant pollen such as organic solvent, low pressure, low and ultra-low temperature preservation. It is proposed that ultra-low temperature preservation technology will become an important direction of pollen preservation and research. Further research on the pollen preservation mechanism is necessary. This paper will provide certain reference for studying long-term and high-efficiency pollen preservation methods of different plants.

In order to further study the plant proliferating cell nuclear antigen (PCNA), this paper summarized the research situation of PCNA, concluded its structural features and functional clues, including PCNA participating in DNA replication, DNA damage repair and cell cycle regulation. At present, PCNA studies are more focused on medical and zoological aspects, the reports on PCNA in botany are few and relatively backward. But some papers have reported that PCNA regulates DNA replication and participates in DNA replication in order to ensure the normal growth and development of plants. Thus, the function of plant PCNA is worth further research.

The objective of this paper is to study the flower morphological structure and flowering characteristics of Fraxinus, and to provide a theoretical basis for its pollination and fertilization. In this paper, three varieties of Fraxinus (‘Lu la No.2’, ‘Lu la No.5’ and ‘Jinjian’) were selected to observe their flowering characteristics and morphological structure of flower. The results show that the flowering period of male plants of Fraxinus is 11-13 days, which is 13-15 days earlier than that of female plants. The flowering period of the female plants of ‘Lu la No. 2’ is only 5-6 days. The small flowers of the 3 Fraxinus varieties are dense without corolla. Their bracts become 2 lobes after flowering, and the calyx is bell-shaped with 4 deep lobes. The male flowers reveal boat-shaped anthers and extremely short filaments accompanying their blooming. The female flower reveals the pistils after its bracts are cracked and its stigma is split into two at maturity and becomes pink, and its peduncle is extremely short. Shield hairs are observed on the bracts and calyx surface of the three Fraxinus varieties under scanning electron microscope, and the morphology of shield hairs differs between different varieties. The anther and pollen structure are not significantly different between ‘Jinjian’ and ‘Lu la No.5’. There are significantly irregular folds on the entire pistil surface of ‘Lu la No.2’. The study lays a foundation for further research on the breeding of Fraxinus and the innovative utilization of Fraxinus germplasm resources.

To study the mosquito problem caused by mosquito breeding by different types of plant communities in residential area, the mosquito breeding status of plant planting communities and common plants in 10 residential areas in Kunming was analyzed. The typical sample plot survey method is adopted to study the directly collected mosquito quantity in the plant space of the communities from 17:00 to 20:00 after rain in the four seasons, and investigate the mosquito breeding quantity of each layer of arbors, shrubs and grasses in the artificial plant community. And SPSS was used to analyze the differences of mosquito breeding affected by plant communities and seasons. The results showed that the plant communities in the 10 residential areas were mainly arbor-shrub-grass, arbor-shrub / arbor-grass, shrub-grass and monolayer; the mosquito breeding mount of the four community types was not significantly different in winter and spring, but there was significant difference between shrub-grass and monolayer in summer and autumn. Among the four types of plant communities, the mosquito breeding amount of monolayer is the least, and that of shrub-grass is the most. Taking into consideration the current status of plants in residential areas in Kunming City, the best optional plants for landscape can be Yulania denudata, Chlorophytum comosum and Cerasus.

To explore the distribution characteristics of soil arbuscular mycorrhizal fungi (AM fungi), and promote the development and utilization of underground AM fungi resources, the distribution characteristics of rhizosphere AM fungal communities of four common plants (Symplocos stellaris, Loropetalum chinense, Camellia fraternal and Lindera glauca) of typical evergreen broad-leaved forests of Lushan Mountain in summer were investigated according to the method of spore morphology classification. The results showed that 44 AM fungal species (4 dominant species, 5 most common species, 12 common species, and 23 rare species) were isolated and identified. (1) There were significant differences in root colonization rate among different plants. The root colonization rate was positively correlated with the spore density and species richness of AM fungi in dominant and most common species, while negatively correlated with them in common and rare species, and the correlations were both not significant. (2) There was no significant difference in total spore density of AM fungi, while significant differences were found in species richness of AM fungi among different plants. In addition, there was no significant difference in the spore density of AM fungi of common species and the species richness of AM fungi of most common and rare species among different plants. (3) A negative correlation between spore density and species richness was found in AM fungi with different dominance. There was only a significantly negative correlation between the spore density of dominant species AM fungi and the spore density of common and rare species AM fungi. (4) Soil nutrients (total nitrogen, total phosphorus, total potassium, ammoniacal nitrogen, and nitrate nitrogen), pH and soil water contributed less to the distribution of AM fungi. However, the distribution of AM fungi was mainly affected by soil nitrogen. AM fungi of various dominant degrees were affected differently by soil nutrients, pH and water (rare species > common species > most common species > dominant species). The symbiosis pattern between common plants and AM fungi might be dominated by dominant and most common species, and supplemented by common and rare species of evergreen broad-leaved forests of Lushan Mountain in summer. According to the symbiosis pattern, AM fungi resources of plant rhizosphere were abundant and unevenly distributed; the degree of symbiosis between AM fungi and plants was determined by the different dominance of AM fungi; the interaction between AM fungi with different dominance was small; AM fungi were less affected by soil nutrients (total nitrogen, ammonia nitrogen, nitrate nitrogen, total phosphorus, and total potassium), pH and water, however, AM fungi of various dominant degrees were affected differently by soil nutrients, pH value and water.

In order to study the changes of phytoplankton community in fish-shrimp-shellfish integrated multi-trophic aquaculture seawater ponds and provide a scientific basis for the optimization of culture model and the ecological regulation of aquaculture ponds, sampling and detection were carried out regularly to analyze the phytoplankton community in water and its correlation with nutrient content during the culture period. The results showed that the species number of phytoplankton in the ponds was higher than that in the natural sea areas. The cell density of phytoplankton in the ponds was higher than that in the natural sea areas in the middle and late stage of culture, except that it was slightly lower in the early stage of culture. Skeletonema costatum was the dominant species in the early stage of culture, Scippsiella trochoidea was the absolute dominant species in the middle stage, and Skeletonema costatum, Karenia mikimotoi and Scippsiella trochoidea were the main species in the later stage. The fluctuations of phytoplankton diversity index (H') and evenness index (J) in the ponds were significantly greater than those in the natural sea areas. It showed a trend of succession of phytoplankton community in the ponds from diatoms to dinoflagellates, while diatoms were absolutely dominant in the natural sea areas. There was a significant correlation between the cell density of Karenia mikimotoi and the content of active phosphate.

To protect the plant resources of the desert grassland in Nilka, plant species of the desert grassland in Nilka were investigated through field investigation and making quadrat. The results show that: there are 98 plant species (subspecies) belonging to 68 genera of 23 families in the desert grassland in Nilka, and Nilka is rich in plant species, with little harmful plants. Chenopodiaceae, Composites and Poaceae are the dominant families with 54 plant species (subspecies); there are many species of small family and single family, including 12 plant species belonging to single family. Sorted by economic groups, Legumes, Poaceae, Chenopodiaceaes, Compositae, Sedge and mixed grasses account for 8.16%, 13.27%, 27.55%, 14.29%, 3.06% and 33.67%, respectively; sorted by feeding value, the percentage of excellent plants, good plants, general plants, low grade plants and poisonous plants is 14.29%, 27.55%, 36.73%, 16.33% and 5.10%, respectively.

With the widespread planting of Bt cotton, cotton pest composition has been changed, and the control strategy should be made to adjust to it. Crop structural adjustment is an important biological and agricultural measure for controlling pests and diseases, planting trap or repel plants in cotton field can reduce the outbreaks of pests and the application of chemical pesticides. It is found that there are more than 30 kinds of trap or repel plants which have been applied to cotton pest control, and according to the action mechanism, they could be divided into three different categories: traditional trap plants, preserve natural enemy trap plants and repel pests’ plants. In this paper, the methods of reducing pests and protecting natural enemies by planting trap or repel plants were reviewed to provide reference for integrated pest management (IPM) in cotton field.

This study analyzed journal papers and patents in the field of major plant epidemic at home and abroad from 2011 to 2020, explored current situation and cutting-edge trends of plant epidemic research, aiming to provide valuable reference for the research innovation in this field and the construction of plant epidemic prevention and control system in China. The bibliometric method was used to sort out the paper publishing countries, journals and cited frequencies in the field of major plant epidemics at home and abroad from 2011 to 2020 in Web of Science core collection, and the research frontiers and hotspots were obtained by keyword analysis. The regional distribution and technical fields were analyzed by patentometrics. Scientific and technological innovation in major plant fields in the world developed steadily, and the number of published papers and patents continued to rise. China ranked first in the total number of published papers and patents in the world, but the degree of international cooperation and the citation frequency of papers were low. China had a large number of authors with high publication volume, but the degree of international cooperation among authors was low. Research hotspots in this field mainly focused on disease identification and control, and chemical ecology of diseases and pests, such as drug resistance monitoring, pesticide risk assessment, and research on biological functional genes. Although China has strong research and development strength in this field, it still needs to improve exchanging and learning ability in domestic and foreign advantageous fields to enhance its influence, and actively carries out international technical research cooperation, so as to provide strong support for the development of long-term effective control of plant epidemic.

The Chinese scholar tree (Sophora japonica L.) is an important garden plant and medicinal plant in China. The study aims to explore the function of Sophora japonica in inhibiting plant pathogens. The inhibitory activities of branch extracts by different polar solvents (ethanol, petroleum ether, ethyl acetate, n-butanol and water) against four plant pathogens were determined by using growth rate method, and the chemical components of ethyl acetate extract were analyzed by GC-MS. The results showed that the extracts of Sophora japonica branches by different solvents had significantly different inhibitory effects against four plant pathogens. Ethyl acetate extract had the best antifungal effect, and its toxicity to Colletotrichum gloeosporioides was the highest, with an EC₅₀ of 2.58 mg/mL at 48 h, followed by its toxicity to Ectohoma multirostrata, Botrytis cinerea and Fusarium foetens. The main chemical components of ethyl acetate extract were aliphatic and terpenoids, and the highest content was octadecyl pentafluoropropionate (14.77%). The antifungal active substances in the branches of Sophora japonica were mainly concentrated in the ethyl acetate phase, followed by n-butanol phase, water phase, and petroleum ether phase.

To screen out the optimum growth condition of water dropwort with high yield and better quality, Japan water dropwort was used as the test material, growth experiments were conducted with indoor LED lights under different photoperiods. Four light/dark alternates (3.5 h/2.5 h, 7 h/5 h, 14 h/10 h, and 10 h/14 h) were set, and the growth parameters, such as the content of vitamin C, total flavonoid, soluble protein, photosynthetic pigment and nitrate, were measured to explore the effects of photoperiod on the growth and quality of water dropwort. The results showed that prolonging illumination from 10 h (10 h light/14 h dark) to 14 h (7 h light/5 h dark-7 h light/5 h dark) could promote the plant height, total yield, and leaf quality of water dropwort.

The paper aims to solve the problem of urban pollen period forecast. In this study, four major woody plants (i.e. Ulmaceae, Cupressaceae, Salicaceae and Pinaceae) in Beijing urban areas were selected as the research objects. Based on four accumulated temperature phenological models (i.e. Spring Warming, Alternating, Sequential and Parallel), using the pollen concentration data of 2012-2019 from Beijing Meteorological Bureau, the pollen period of each plant was modeled. The results show that the pollen start dates of these four woody plants are significantly affected by vernalization, that is, the stimulation of cold temperature in winter would lead to an earlier pollen season in spring. Comparing the results of these four different models, it is found that the optimum model for Ulmaceae, Cupressaceae and Pinaceae is the Alternating model, the RMSE of this model is between 1-3 days, and the determination coefficient R² is between 91%-95%. However, the best model for Salicaceae is Sequential model, RMSE is less than 2 days, and R² is 92.8%. This shows that the phenological model based on accumulated temperature can effectively simulate the pollen initiation period of woody plants in Beijing, which has certain significance for the simulation study of plant phenological stage.

Alternative splicing is widespread in plants and is the main source of transcriptome and proteome diversity in organisms. With the development of science and technology, the research methods of alternative splicing have gradually become simple, convenient and efficient, and more and more alternative splicing events have been discovered in plants. The article mainly introduces the mechanism and research methods of alternative splicing in plants, as well as the latest research progress of alternative splicing in several plants, and puts forward suggestions on the research direction in the future.

This paper briefly analyzed the characteristics of the control technologies of heavy metal pollution in farmland in southern China. 40 species of hyperaccumulators for cadmium, arsenic, copper and lead in China were collected, classified and summarized. Based on the existing heavy metal hyperaccumulators in China, the selection and cultivation direction of remediation plants in farmland with excessive heavy metals in southern China were discussed. Suggestions for the application of hyperaccumulators in the remediation of farmland with heavy metal cadmium, arsenic, copper and lead pollution were put forward.

The increasing deterioration of the environment has forced people to abandon the concept of high-fertilizer production and shift to the concept of low-fertilizer green production. This study reviewed different metabolic levels, and morphological, physiological and molecular responses of plants from five aspects: enzymes involved in nitrogen metabolism, nitrogen assimilation pathways, primary metabolism, secondary metabolism and nitrogen metabolism-related genes under low nitrogen stress, discussed the low nitrogen tolerance strategies of plants at different growth stages, and expounded the enzymes related to nitrogen use efficiency (NUE) and their regulatory mechanism in the process of resisting nitrogen stress. It is proposed that in the future, according to the differences of low nitrogen tolerance of different plants or different growth periods of the same plant, and the relationship of key gene expression products, the molecular response mechanisms of plants under low nitrogen stress could be systematically and comprehensively studied from multiple disciplines and perspectives, so as to provide theoretical reference for the research on plant nitrogen metabolism involved in low nitrogen stress.

To systematically analyze the status quo of research and the application prospect of plant immune inducer, this study collected relevant data from Web of Science and CNKI China, and used CiteSpace software and analysis tools like Excel to conduct visualization analysis of the literature on plant immune inducers published in domestic and foreign journals from 1985 to 2021. At present, the literature related to plant immune inducers has a fluctuating and rising trend. According to the WOS database, among the foreign language literature, the publications related to plant immune inducers mainly comes from the United States, China, Japan and other countries. Through the distribution analysis of high-frequency keywords, the research hotspots are salicylic acid plant immune inducers, amino oligosaccharides, Ralstonia solanacearum, and technologies concerning straw biological reactor and crop yield increase. Among the highly co-cited articles, those about the mechanism of plant immune inducers account for the main part. The results of this bibliometrics analysis could provide ideas and methods for the research and technology application of plant immune inducers in China.

The new plant variety right is an important intellectual property particularly to seed field, which is of great significance to protect the interests of breeders and promote innovation in seed market. In current judicial practice, problems such as the low legislative level of new plant variety protection, serious homogenization of plant varieties in seed market, and the difficulty for breeders to protect rights are becoming more and more prominent. How to improve the protection system of new plant variety in China has become the key to effectively resolving disputes over the protection of new plant variety. By analyzing problems and their causes of the protection system of plant variety at this stage and drawing on the experience of relevant regulations of new plant variety protection system in the United States and Japan, the study aims to explore the protection mode of new plant variety in line with China’s national conditions and the status quo of agricultural development, so as to promote the construction of a major agricultural country and improve international competitiveness.

To understand the influence of herb extract and plant essential oil on the stress resistance of tea plant and to develop environment-friendly technology to improve tea plant resistance to various stresses, in this study, herb ethanol extracts (from the fresh shoots of rosemary, perilla and mint ) and biotic plant essential oil (methyl salicylate oil and methyl dihydrojasmonate) were made into 0.1% water solution which was used as external treatment agent to be sprayed on tea plants (7500 L/hm² for each treatment, twice continuously) in early December. The results showed that after treatment, the content of amino acids in tea leaves was increased by 27.8%-55.6% and the content of polyphenols was increased by 3.93%-24.2%. The relative content of dialdehyde in tea leaves, except those treated by mint extract, was decreased by 9.2%-32.8%. The enzyme activity analysis showed that the polyphenol oxidase activity of tea leaves was increased by 1.89-4.35 times, the lipoxygenase activity was increased by 1.41-2.58 times, and the superoxide dismutase activity was increased by 1.98-15.7 times, respectively. The phenylalanine ammonia lyase (PAL) activity was decreased except the treatment by rosemary and perilla extract. The expression of CsOPB3 in tea leaves, a key gene of jasmonic acid signal pathway, was significantly up-regulated after treatment with dihydrojasmonate, rosemary and perilla extract, but down-regulated after treatment with peppermint extract and holly oil. The scavenging ability of water extract of fresh tea leaves treated with herb extract or plant essential oil to superoxide free radical was increased by 1.3-2.9 times. The study shows that spraying herb extract and plant essential oil in early winter tea garden can improve the adaptability of tea plants to low temperature. According to the common indicating role of physiological indexes measured in this study to evaluate tea plants against other abiotic stresses or plant diseases and insect pests, the results further reveal that different herb extracts and plant essential oils used in the study could have a certain application value for tea plants against more abiotic and biotic stresses.

It is of great significance to study the responses of photosynthesis, stomatal conductance and transpiration of plants to photosynthetic active radiation, to evaluate the utilization efficiency of light energy and water and the plant growth under different light conditions. In the present study, three vine plants (Vinca major, Passiflora caerulea and Campsis grandiflora) were used to measure their gas exchange and chlorophyll content under different light levels. The photosynthetic parameters were estimated according to non-rectangular hyperbola model. The results showed that: the light saturated point and the maximum net photosynthetic rate of P. caerulea were 1850 μmol CO₂/( m²·s) and 10.9 μmol CO₂/(m²·s), respectively, significantly higher than those of V. major and C. grandiflora. V. major was strongly resistant to weak light with a lower light saturation point of 580 μmol CO₂/( m²·s), significantly lower than that of the other two plants. There was no significant difference in apparent quantum yield among the three plants, indicating they had similar ability to use weak light. The chlorophyll content of V. major was significantly higher than that of P. caerulea, but P. caerulea had a higher ratio of chlorophyll a/b than V. major. P. caerulea had a wide range of light adaptation and stronger utilization of low and high light. Therefore, the photosynthetic capacity of P. caerulea is higher than that of V. major and C. grandiflora.

In order to understand the population status and suitable habitat types of Sphaeropteris lepifera, a rare and endangered plant, this study conducted field investigation and analysis on the distribution areas of S. lepifera in Zhejiang and Fujian, hoping to provide reference for the original habitat protection and field regression of S. lepifera. We analyzed the vegetation types of S. lepifera distribution area, evaluated the distribution status, summarized the existing problems, and proposed protection suggestions after extensively collecting the relevant investigation and research data of S. lepifera, consulting with experts and scholars, and conducting field visits and surveys. The results show that the change of living environment and the destruction caused by human activities are the main reasons for the decrease of S. lepifera in the wild. It is necessary to strengthen the research on the original habitat protection, artificial breeding of seedlings, field regression and endangerment mechanism investigation to increase the number of seedlings and establish ex-situ conservation population of S. lepifera, thus promoting the restoration of its wild population and habitat and protect its germplasm resource.

The CRISPR/Cas9 system is a simple and efficient targeted gene editing technology, which has important application value in plant genetic improvement and crop genetics and breeding. This research mainly introduced the principle and construction method of CRISPR/Cas9, discussed the application and research progress of CRISPR/Cas9 in plant gene function and gene expression regulation, plant genome site-specific editing and crop molecular breeding in recent years. We analyzed the main influencing factors and the optimizing methods of this gene editing technology, as well as problems in its application and the solutions to the problems, and discussed the future development direction of the technology, thus providing reference for the application of CRISPR/Cas9 in plant genome editing and crop genetics and breeding.

Botanical insecticides are secondary metabolites produced by plants, which provide rich resources for research and development of insecticides because of their specific biological activities. They are alternatives to organic synthetic chemical pesticides. In this study, a brief history and current status of plant-based insecticides, and their active ingredients and modes of action were reviewed in detail, and the problems and development prospects of plant-based insecticide research were discussed. This study will provide reference for the development of more botanical insecticides.

The purpose of the study is to reveal the change trend of woody plants’ phenophase and its response to climate change in the forest-pasture ecotone, and provide meteorological reference for guiding the ecological restoration projects of sand fixation and wind prevention. The phenophase observation data of three kinds of woody plants, Ulmus pumila, Populus simonii Carr and Syringa oblate, and simultaneous meteorological data from Ewenki meteorological experimental station in Inner Mongolia from 1994 to 2019 were used to analyze the influence of climate change on the phenophase of woody plants in the forest-pasture ecotone at the western foot of the Great Khingan Mountains by linear tendency estimation, Pearson correlation coefficient, scatter diagram and other methods. The results showed that in the 26 years, the temperature increased significantly in the plant growing season in this region, and the change trend of precipitation was not obvious. The flowering period of Ulmus pumila, Populus simonii Carr and Syringa oblate was earlier, and the late abscission period was postponed by 9.6, 7.5, and 8.5 d every 10 years, respectively. The growing season was prolonged significantly, and the average growing season was 160-164 d. The air temperature was the key meteorological factor affecting the flowering period in spring and the late abscission period in autumn. The advanced flowering period of the three woody plants had a significantly negative correlation with the rise of temperature in spring, and the postponing of the late abscission period was significantly and positively correlated with the rise of temperature. In conclusion, under the background of climate warming, the earlier flowering period and the delayed late abscission period of the three woody plants have been observed, and the growth period is extended. The postponing days of the late abscission period are more than the earlier days of the flowering period, indicating that climate change has a more obvious impact on the late abscission period of woody plants, and the late abscission period has a greater contribution to the extension of the growing season. The phenophase change of woody plants is mainly influenced by temperature and has little correlation with precipitation in the forest-pasture ecotone at the western foot of the Great Khingan Mountains.

After absorbed by plants, the heavy metals from soil will accumulate in different parts of the plant through lateral and vertical migration. The lateral migration includes the pathways of symplast and apoplast. The vertical migration includes the pathways of xylem and phloem. The factors affecting the migration of cadmium, lead and zinc in plants include barrier structure, transport, physiological metabolites and energy supply. The study of the migration characteristics of heavy metals in plants provides a certain basis for the phytoremediation of soil polluted by heavy metals and the safe utilization of agricultural soil.

In recent years, the frequent occurrence of plant diseases has seriously affected the production and development of China’s agriculture. In order to improve plant disease resistance, this paper summarized the application of genomics, transcriptomics, proteomics and metabonomics in plant disease resistance research. At the same time, it summarized the methods of breeding disease-resistant varieties, biological control and plant disease monitoring technology to reduce plant diseases, analyzed different plant disease resistance mechanisms at molecular level, and revealed the close relationship between related disease resistance genes and their growth and development. This paper pointed out the shortcomings of omics technology application in plant disease resistance. There are still some functional proteins with low abundance or low molecular weight that have not been identified. Some suggestions were put forward, such as improving the sensitivity of detection technology, and perfecting gene and metabolic database. The continuous development and innovation of omics technology has brought new opportunities for the prevention and control of plant diseases. It will be helpful for breeding resistant varieties, detection and control of pathogenic bacteria, and improvement of plant resistance, so as to promote plant growth and increase crop yield.

To find out the current situation and characteristics of plant greening resources in Beibu Gulf coastal city parks of Guangxi, 52 standard plots of 10 parks in Beihai, Qinzhou and Fangchenggang of Guangxi Beibu Gulf were investigated by typical random sampling method. The statistical results show that there are 183 species of plant resources in this region, belonging to 60 families and 140 genera, including 1 species of pteridophytes in 1 family and 1 genus, 7 species of gymnosperms in 5 families and 7 genera, 175 species of angiosperms in 54 families and 132 genera. The arbor layer has the most abundant species, with 100 species, accounting for 55% of the total. The second is shrub layer, which has 56 species, accounting for 30% of the total. The herbaceous layer has the fewest species, only 27, accounting for 15% of the total. The plant system composition reflects the tropical, subtropical and coastal characteristics. Most species have regional landscape characteristics, mainly Roystonea regia, Archontophoenix alexandrae, Casuarina equisetifolia and etc. It is suggested to enhance the screening and application of native coastal plants for the greening construction of Beibu Gulf coastal areas.

The status quo and latest progress of research on botanical insecticides against stored grain pests around the world were reviewed, and the industrialization of botanical insecticides in China was analyzed. Botanical insecticides exhibit a very broad application prospect due to its advantages of diversified insecticidal active compounds, complicated mechanisms of insecticidal action, and being environment-friendly. Studies on botanical insecticides against stored grain pests have been carried out extensively abroad, and most of them focus on the identification of active compounds, insecticidal efficacy and the action mechanism. Currently, there are only a few studies on the application of botanical insecticides for controlling stored grain pests in China, and only limited insecticides have been commercialized. Therefore, further explorations are needed. By summarizing the studies at home and abroad, the problems in the application of botanical insecticides for controlling stored grain pests were analyzed, the corresponding suggestions were put forward, and the future development directions were discussed, aiming to provide reference for future research and industrial application of botanical insecticides in China.

Stable carbon isotope measurement is not limited by time and space, and the measurement process is simple and accurate. In order to eliminate the defects of conventional methods for measuring water use efficiency (WUE), stable carbon isotope tracing technology can be used in the WUE of indicator crops. The basic principle of stable carbon isotope fractionation was reviewed in this paper. The relationship between the stable carbon isotope fractionation characteristics and WUE, and the application of stable carbon isotope fractionation in drought resistance and water saving breeding were analyzed from plant organs, climate factors and water conditions. The stable carbon isotope fractionation characteristics of different photosynthetic plants show that WUE is correlated with carbon isotope ratio (δ¹³C) and carbon isotope resolution (Δ¹³C), and the δ¹³C values of different plant organs are different. Rainfall, light intensity and duration, and soil moisture have significant effects on the δ¹³C values and WUE. Therefore, δ¹³C and Δ¹³C, the two stable carbon isotope indexes can indicate the high WUE and drought resistance of plants better, and provide a theoretical basis for improving plant WUE and breeding drought-resistant varieties.

The main active ingredient of Silybum marianum L. Gaertn is the flavonoid silymarin, which can inhibit damage, treat cardiovascular and cerebrovascular diseases, and has antitumor effect. It is especially effective in liver injury treatment. In this study, the current research progress of the medicinal plant Silybum marianum L. Gaertn is reviewed in terms of botanical characteristics, cultivation techniques, active ingredients and pharmacological effects. The study aims to provide reference for further improving the cultivation technology and developing the medicinal value of Silybum marianum L. Gaertn. It is found that Silybum marianum L. Gaertn can regulate plant growth and development under abiotic stress by affecting secondary metabolites, antioxidant enzyme activities and osmoregulatory substance content. In addition, the application of exogenous plant growth hormone can resist the external stress and promote the plant growth and development of Silybum marianum L. Gaertn. Moderate abiotic stress such as drought and salinity and alkalinity can improve the accumulation of active ingredients in Silybum marianum L. Gaertn.

The study aims at providing data reference for the research of nodule nitrogen fixation in legumes. Relevant papers on the effects of nodule nitrogen fixation on legumes in CNKI and Web of Science Core Data Platforms (WOS) from their establishment to early 2020 were searched. Bibliometrics methods and CiteSpace 5.5.R2 software were used to analyze and visualize the publishing time, journals, research institutions, countries, research topics and keywords of the literature. A total of 4886 Chinese and English papers were found, including 3015 Chinese papers and 1871 English papers. The number of published papers increased gradually, and the United States, China and Brazil were the top three countries with most published papers, while French National Academy of Agricultural Sciences was the institution which had the largest number of published papers. The papers were published on 940 journals, mainly journals of microbiology, soil and agriculture. Among them, Soybean Science and PLANT AND SOIL published more papers in this field. The effects of nodule nitrogen fixation on stress resistance of legumes and the gene and genetic diversity of rhizobia are the main directions of current research. At present, the research groups on nitrogen fixation in legumes are relatively stable, and the research still receives attention from scholars at home and abroad. The occurrence and regulation mechanism of nodule nitrogen fixation and the gene and genetic diversity of rhizobia are current research hotspots and possible future research trend.

The paper aims to explore the characteristics of medicinal plant resources and the floristic composition of medicinal plants in Lingdong District of Shuangyashan City and their genetic relationship with plants floristic composition in adjacent areas. The research was carried out based on the Fourth National Survey of Traditional Chinese Medicine Resources and the theory of plant geography. There were 272 species of medicinal vascular plants belonging to 71 families and 199 genera in Lingdong, which were dominated by angiosperms. In the composition of families and genera, single species family, oligotypic family, monotypic genus and oligotypic genus constituted the main body of plant resources in this area. Perennial herbs were the main form. Whole herbs were the main medicinal parts. 36 species were investigated, and the total reserve was 1808736.85 kg. The floristic components of seed plants were rich, mainly temperate components, and many components coexisted. The R/T value of Lingdong was the lowest and the temperate components were the highest. The results of cluster analysis showed that the genetic relationship between Lingdong and Hegang was the closest. The wild medicinal plant resources are rich in Lingdong, the geographical elements of life form, medicinal parts and families and genera are obviously diverse, and the floristic affinity is affected by many factors.

According to The List of Rare and Endangered Plants in China (volume 1), The Rare and Endangered Plants in China Plant Red Data Book - (volume 1) and The National Key Protected Wild Plants List (first batch), we found that there are 31 species of national key protected plants in Ledong County of Hainan, which belong to 26 families and 29 genera, including 21 families, 23 genera and 23 species of angiosperms, 4 families, 4 genera and 4 species of gymnosperms, 1 family, 2 genera and 4 species of ferns. The study shows that the flora of the national key protected plants in Ledong County has obviously tropical properties, and distributes mainly at the middle altitude of 650-750 m and slope of 20°-30°. The purpose of this study is to provide a theoretical basis for planning management and scientific protection of national key protected plant resources in Ledong County by studying the distribution characteristics of the resources.

The SWEET gene family of plant sugar transporters is a class of important sugar transporters discovered in recent years, which plays an important role in plant growth and development, physiological metabolism, and resistance to stress by regulating the transport and distribution of sugar in plants. SWEET gene has different biological functions in different species and plays an important role in plant life activities. In this study, we reported the research status of the protein structure, transport mechanism and biological function of the SWEET gene family in plants, aiming to provide a theoretical basis for further study on other structures and functions of SWEET gene family.

microRNA (miRNA) is a kind of endogenous non-coding small RNA, it plays significant role in the whole process of plant growth and development, and it is an important regulator in the gene expression. miR172 is an important member among various miRNA families. In order to understand the role of miR172 in plants more intuitively, the authors classified and summarized the research progress of miR172 in regulating plant growth and development, as well as plant response to adversity stress. miR172 is involved in many processes, such as vegetative phase transition, flowering, floral organ development, internode length, plant commodity organs’ development and plant response to adversity stress. The authors think that miR172 still has many unknown functions in plants. Therefore, it is an important research direction to deeply explore more roles of miR172 in plant growth process in the future. Based on this, the function and molecular regulation mechanism of miR172 should be deeply analyzed, which will lay a theoretical foundation for artificially using miR172 to regulate plant growth and development.

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.

Bared soil causes the decline of soil fertility in the banana cropping system, which is one of the crucial factors limiting the sustainable development of banana industry. Plant covering could be an effective way to alleviate the decline of soil fertility in banana cropping system. The functional diversity of soil microbial communities could sensitively reflect the variation of soil properties, and is an important indicator for assessing soil quality. In this study, conventional planting method with bare soil between rows was used as control (CK), natural weeds covering (NW) and artificially planted legumes [Macroptilium atropurpureum (DC.) Urb.] covering (CP) were taken as the treatments in banana cropping system. The effects of plant covering on the functional diversity of soil microorganisms under banana cropping system were studied with microbial Biolog identification technology. The results showed that the carbon utilization of soil microorganisms had significant differences under different covering plants, ranked as: CP> NW> CK. Compared with CK, plant covering significantly (P<0.05) improved the Richness Index, Shannon-Wiener Index and Simpson Index of soil microorganisms under banana cropping system; the soil microorganisms showed a high utilization rate of sugars, amino acids and carboxylic acids. The soil microorganisms under NW showed better utilization of carboxylic acid carbon sources, and the soil microorganisms under CP showed better utilization of sugars and amino acid carbon sources. Different covering plants had significantly affected soil microbial community functional diversity under banana cropping system. Compared with CK, CP could improve the soil microbial community and effectively mitigate the degree of soil degradation. Promoting soil microbial diversity by covering plant diversity, the healthy and sustainable utilization of soil could be achieved in banana industry.

The purpose is to find out whether Thymelaeaceae plants of the same family as Stellera chamaejasme have the potential to become plant resources for controlling pathogenic fungi, and to explore new ways for screening and preparing effective and safe botanical pesticides. Five test materials including Stellera chamaejasme, Lndian wikstroemia, Daphne giraldii, Daphne genkwa, and Edgeworthia chrysantha, were used as representatives of the plants in the Thymelaeaceae family. The results showed that Stellera chamaejasme and Edgeworthia chrysantha performed the best in all extracts, especially against various pathogens of Fusarium wilt. The inhibitory rate at higher concentrations was close to 100%. The inhibitory effect of Daphne giraldii extract on cucumber target spots and strawberry red central pillar was the best among all the extracts, and the EC₅₀ value was 0.925 and 0.920 mg/mL, respectively. Lndian wikstroemia had the worst performance among the 5 kinds of plant extracts of Thymelaeaceae, but it had a good inhibitory effect on tomato wilt and cucumber anthracnose pathogens, and the EC₅₀ value was less than 1.1 mg/mL. The results show that the extracts of five Thymelaeaceae plants have good antimicrobial activity against pathogenic fungi, indicating that Thymelaeaceae plants can be used as screening targets for new plant-derived pesticides.

5-Azacytidine is a DNA methylation inhibitor, which can regulate gene expression by reducing the methylation level of DNA, thus providing epigenetic regulation for biological growth and development. It has been widely studied as well as applied in animal and medical field and its research and application in plant gene expression regulation have been reported increasingly in recent years. This review provided an overview of the types of plant DNA methylation, the causing factors, the influencing factors and the role of inhibitors, focusing on the regulation and effects of 5-Azacytidine on plant gene expression levels. The effects of 5-Azacytidine on growth and development, stress adaptation, fertility regulation and secondary metabolism in rice, wheat, cotton and other important crops were summarized, and a new insight for the study and application of epigenetic regulation of plant gene expression was also presented.

The study reviewed research progress of Dendrobium plants in the fields such as genetic diversity analysis, relationship comparison, fingerprint and genetic linkage map construction, variety identification, and germplasm purity identification, analyzed main problems of SSR molecular markers in the research of Dendrobium plants, and proposed that the future development of SSR molecular markers should be aimed at more groups and varieties of Dendrobium, adopt the latest third-generation sequencing technology to mine trait-associated markers, and formulate the unified national or industrial standards for variety identification markers, thus providing more reference for the in-depth application of SSR molecular marks in Dendrobium.

This paper briefly describes the process of early bolting of Umbelliferae rhizome medicinal plants, clarifies the causes and influencing factors, and speculates that the early bolting is related to the expression ability of some genes regulating flowering. In addition, it is considered that the hormone synthesis in plants can regulate the occurrence of early bolting to a certain extent. Specific genes are differently expressed in the synthesis, metabolism and signal transduction of plant endogenous hormones, resulting in early bolting. It is proposed that we can start from the molecular gene level of plant endogenous hormones and the action mechanism of hormones, to inhibit early bolting rate by changing the growth conditions of rhizome medicinal plants of Umbelliferae or applying exogenous hormones, which will be of great significance to improve the yield and quality of the medicinal plants.