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.

In order to provide the scientific basics for quality assessment of organic fertilizer commonly used In tobacco as well as rational use of organic fertilizers, this article analyzed the main components of organic fertilizer commonly used in tobacco, classify as well as evaluate the quality of the organic fertilizer, the main components of these organic fertilize were carbon, nitrogen and phosphorus factor. Five types of the organic fertilizer was divided into four quality levels: the first level was cake that contains of high phosphorus, nitrogen, organic matter and nutrients; the second level was ryegrass and sweet potato vine that contains of medium nitrogen, high organic matter and organic nutrients; the third level was pig manure and chicken manure, the feature of this level was high content of nitrogen and phosphorus but low organic nutrients; the last level was cow dung, wheat straw, corn stalks and so on, the feature of this level was poor content of nitrogen, phosphorus, organic matter and organic nutrients. We should take rational application of various types of organic fertilizer based on the actual soil conditions.

Although overall level is not high, tobacco seedling has basically realized intensive and standardization in China. The cost of seedling is expensive, the links of technology are complex, cutting leaves and disinfection need much time and labor, has limited the sustainable development of production of tobacco further. The existing intensive seedling ideas and technology system has been difficult to adapt to the new situation of development. For reducing the cost of seedling improving the quality of seedling, the paper has stated the concept of intensive simplified and labor saving seedling of tobacco, summarized the advantage and disadvantage of the tobacco seedling in current situation, formed simplified and labor saving seedling technology including the way of simplified and labor saving seedling, ecological seedling substance, mechanical and digital technology, and looked intensive simplified and labor saving seedling of tobacco into future.

For the method of rapid diagnosis of Ralstonia solanacearum contain in tobacco fields, this paper based on the comparison result of the five whole-genome of the published genomes of Ralstonia solanacearum, designed nine pairs of specific primers of Ralstonia solanacearum, and has achieved three pairs of primers for specific amplification of Pseudomonas solanacearum by screening and verification. The application of the screened primers could be used as an effective method to do specific detection of tobacco Ralstonia solanacearum in the soil. As a preliminary conclusion, the lowest detection rate of Ralstonia solanacearum in the soil was 2×106/g. Thus, it’s a rapid and accurate new way for detection of tobacco Ralstonia solanacearum in the soil.

The aim was to investigate the effect of salt stress on the seed germination and physiological characteristics of tobacco. The relative germination potential, relative germination rate, root length, chlorophy ll content, cell membrane permeability, MDA content and proline content were measured. With the increase of NaCl concentration, the relative germination potential, relative germination rate, root length, chlorophy ll content kept decreasing; Cell membrane permeability and proline content kept increasing; the malondiadehyde content increased at first, and then decreased with the increase of NaCl concentration. When the concentration of NaCl was up to 1.2% , the tobacco leaf chlorophy ll content declined to the maximum extent and the malondiadehyde content reached maximum value which provided a reliable basis for the study of tobacco salt tolerance mechanism.

To find new resistance genes and study perilipin gene 8-3 related to Sclerotinia sclerotiorum, a couple of primers containing restriction enzyme sites of Xba I and BamH I were designed to clone the 8-3 from cloning vector pMD19-T-8-3, and the product was digested and lignased with plant expression vector pBI121. The pBI121-8-3 was transformed into LBA4404 and the 8-3 gene was transformed into Nicotiana tabacum 89 mediated by Agrobacterium tumefaciens. 35 resistant lines were obtained, 21 of which were identified as transgenic plants by PCR and sequencing. The further identification of RT-PCR was confirmed that the 8-3 was expressed in the transgenic plants. The transgenic tobacco infected with Sclerotinia sclerotiorum and oxalic acid showed that 8-3 could improve the plants' tolerance level to oxalic acid and enhance the resistance to Sclerotinia sclerotiorum to a certain extent, which laid the foundation for the study of 8-3 gene and plant resistance to Sclerotinia sclerotiorum.

In order to find an effective way to extract RNA in tobacco leaves and provide theoretical basis for tobacco molecular biology research, tobacco leaves were used as material, 3 methods including RNA isolation kit, Trizol method and RNAiso method were used to extract RNA, then RNA were detected by gel electrophoresis and spectrometer. The results indicated that the operation of RNA isolation kit was very easy, but the extraction was the least; Trizol method was convenient and efficient, but there were proteins and a little degradation in RNA; in contrast, the concentration of RNA extracted by RNAiso method was very high and ranged from 100 to 500 ng/μL, A₂₆₀/A₂₈₀ was from 1.8 to 2.0, RNA bands were clear and bright without degradation, and the brightness of 28S band was about twice that of 18S band; RT-PCR result showed that 2500 bp target gene consistent with the reference sequence was obtained, and it could be used in functional verification. Hence, RNAiso method was the best way to extract total RNA in tobacco leaves and had been used in many laboratories.

Tobacco growth information is an important basis for tobacco production management. Through a comprehensive understanding of the application of remote sensing technology in tobacco growth monitoring and yield estimation, the study aims to provide a scientific reference for the use of remote sensing technology in refined tobacco field management. Based on reviewing relevant literatures, the application of remote sensing technology in tobacco growth monitoring and yield estimation was systematically summarized from three scales of ground spectrum, UAV(unmanned aerial vehicle) remote sensing, and satellite remote sensing, and the prospect of further research was also discussed. (1)Based on the ground spectrum, the physiological and biochemical parameters (nitrogen, phosphorus, potassium, biomass, leaf area index, chlorophyll, etc.) of tobacco were estimated by reflectance spectrum and its different transformation forms, spectral index and spectral position variables, providing a basis for the diagnosis of tobacco growth, health status and maturity. Tobacco growth monitoring, yield estimation and quality evaluation could be realized. (2) UAV remote sensing technology could be used to extract tobacco areas on a small scale, monitor and estimate yield, but it could not monitor the subtle changes of tobacco due to the influence of the resolution, terrain and self stability of the camera. (3) With optical remote sensing data such as LandSat, SPOT, MODIS HJ-1, etc., as well as SAR data, by remote sensing image fusion, classification and other technologies, large-area tobacco field disease, growth monitoring and yield estimation could be achieved. The future research will focus on quantitatively studying the tobacco parameters by combining with multi-source and multi-platform remote sensing data, and conducting the dynamic monitoring of tobacco growth process on large scale by assimilation technology, thus to explore the optimal harvest time of tobacco.

To screen effective drugs for controlling tobacco Bemisia tabaci, toxicity test and field efficacy of 3 biological insecticides to B.tabaci were used on tobacco. The toxicity test results showed that the virulence of B.tabaci presented as 0.5% ivermectin EC > 0.5% veratridine Solution > 6% rotenone microemulsion, and the LC50 values of them were 1.396 mg/L, 5.083 mg/L, 12.287 mg/L respectively, which was significantly better than the CK cyhalothrin (LC50 = 30.67 mg/L). Results of field efficacy showed that the adjusted efficiency of 3,7,14 days after treatment of 2000 times of dilution of 6% rotenone microemulsion, 0.5% ivermectin EC, 0.5% veratridine solution were over 70%. Therefore, the 3biological insecticides have no harmful effects on the tobacco field, and the tobacco plants are safe to grow and can be further promoted and applied in production.

This paper expounds the physiological function and the mechanism of absorption and distribution of chlorine. Recent researches on the relationship between chlorine and tobacco quality, the main factors influencing chlorine content and the genetic analysis of chlorine in tobacco were also reviewed. The distribution of chlorine content in domestic tobaccos exists imbalanced phenomenon, mainly manifested as south-low and north- high. The problem of high chlorine in the northern area, especially Huanghuai Tobacco Region remains the influence factor limiting tobacco industrial availability. This article presents that precision agriculture in the direction of the development of tobacco chlorine nutrition, and points out the research of chlorine nutrition in tobacco molecular genetic level were still few studies. Correlation analysis technology was an important means of macro and micro combination on the modern research of chlorine nutrition in tobacco. These conclusions and prospects were to provide reference for the cultivation of tobacco science and the improvement of the quality of tobacco leaf.

Some plants could accumulate glycine betaine by self synthesis so as to alleviate the injury caused by drought, low temperature and salt stress. Meanwhile it could promote the accumulation amount of glycine betaine by genetic engineering or exogenous application for plants which could not make by themselves. This article summarized main research progress on discovery, biosynthetic pathway and applications of glycine betaine in plants, meanwhile evaluated research status, existing problems and application prospect of glycine betaine in tobacco. At last, we concluded that glycine betaine had the popularization and application potential in paddy yield of tobacco for its low cost, little dosage and strong stress resistence.

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.

Tobacco black shank, caused by Phytophthora parasitica var. nicotianae, is an important destructive disease of tobacco, which seriously threatens the sustainable development of tobacco industry. In recent years, great progress on biological control of tobacco black shank has been made. To provide reference basis for biological control of tobacco black shank in the future, the authors reviewed the advances in the studies of biological control microorganisms (bacterium, fungi, actinomycetes) as well as botanical fungicides against the Phytophthora parasitica var. nicotianae, and introduced the biological control mechanisms. In addition, the authors also analyzed new problems in biological control of tobacco black shank under global warming and made an outlook on future research.

Skimmed milk and trisodium phosphate, which have a significant passivation effect on tobacco mosaic virus (TMV), were selected as the research objects. The passivation effect of the combination of skimmed milk and trisodium phosphate (called Yiduling) on TMV-contaminated substrate and leaf-cutting device during floating seedling cultivation was determined by the dead spot method. The effects of Yiduling on viral granules were observed by transmission electron microscopy. At the same time, real-time qPCR was used to quantitatively detect the content of TMV and the relative expression of host defense protein. The results showed that the passivation effect of Yiduling diluent on TMV was time and concentration dependent, and the inhibition rate was significantly different between different treatments. Yiduling mixed with TMV inoculum for 3 minutes completely inhibited the infection of TMV on leaves. The best inhibitory effect was obtained when 500 times Yiduling was used for disinfection for more than 1 min. The passivation effect on TMV was up to 100% when the leaf-cutting device was soaked with Yiduling diluted 500 times for no less than 5 minutes. Different concentrations of Yiduling diluent significantly inactivated the TMV in the substrate and inhibited the infection and morbidity of tobacco seedlings by TMV, and the content of TMV in the substrate decreased by 74.09%-90.26% and the relative control effect reached 54.83%-85.45%. In addition, the tobacco seedling leaves in all treatments with Yiduling were normal and no phytotoxicity occurred. The study of the mechanism of inactivating virus found that the virions after co-incubation with Yiduling diluent were broken into tiny fragments, the coat protein was severely damaged, and the helical structure and columnar shape were basically lost. At the same time, Yiduling increased the enzyme activity of defense enzymes PPO and PAL, and significantly induced the expression of defense genes NPR1, PAL, PR1b and PR1a. In summary, Yiduling can have antiviral effects by directly acting on virion and inducing host resistance.

Sodium percarbonate, a new disinfectant, has been widely used in the sterilization and cleaning of objects, but has not been reported in the surface sterilization of plant seeds and explants. In this study, tobacco seeds were used to study the effects of three sterilizing agents, including sodium percarbonate, sodium hypochlorite and mercuric chloride, on the seed surface sterility and their effects on seed germination and plant growth. Tobacco seeds were treated with 4.0% aqueous solution of sodium percarbonate (active oxygen content ≥0.54%) for 20-40 min and then inoculated directly onto MS medium for germination and growth. While the other two groups were sterilized separately with 33.3% sodium hypochlorite solution (active chlorine content ≥1.65%) for 10 min and 0.1% aqueous solution of mercury for 4 min, then cleaned for 5 times with sterile water and inoculated on the same medium. The results showed that 90% of seeds germinated and no plantlet was contaminated, indicating that the three methods were effectively. The seeds germinated fast and the plantlets grew well by sodium percarbonate and sodium hypochlorite treatments, and the group of sodium percarbonate treatment was slightly better than that of sodium hypochlorite. However, mercury delayed seed germination and inhibited plant growth. In addition, sodium percarbonate eliminates the need for cleaning after sterilization, exhibiting a great advantage. This study established a new method for tobacco seed surface sterilization, which provides a reference for the sterilization of other plants seeds and explants, showing very practical value.

Tobacco is used as the experimental material, with the floating seedling culture, the effects of the best ratio of vermicompost (30% vermicompost+ 30% peat+ 20% perlite+ 20% vermiculite) and conventional substrate on the growth and the metabolizing enzyme activities of tobacco in seedling stage, cluster stage and vigorous growth stage were studied, so as to provide technical reference for the application of vermicompost substrate seedling. The results show that, in the seedling stage, the method of vermicompost seedling culture could significantly promote the fresh weight of leaves, total root length, root volume, root diameter, and root activity, compared with the conventional substrate seedling culture. In the cluster stage and vigorous growing stage, the root growth of tobacco with the method of vermicompost seedling culture is better than that with conventional substrate seedling culture, and the root activity could reach significant difference level, increased by 23.50% and 24.98% respectively. However, there is no significant difference in the activity of nitrogen-transformation-related enzymes between the different seedling culture in the cluster stage and the vigorous growing stage. In conclusion, vermicompost substrate could promote the growth of tobacco at seedling stage, cluster stage and vigorous growing stage, and has a more obvious impact on tobacco root growth indicators, so vermicompost substrate is suitable for tobacco seedling in the field.

To study the mechanism of aphid resistance in tobacco varieties, six tobacco varieties with different aphid resistance were selected and inoculated with aphid in pot experiment. The content change of jasmine acid (JA) and nitric oxide (NO), and CAT activities in tobacco leaves were determined 0, 3, 6 and 9 hours after feeding aphid. The results showed that: after being infested by aphids, the JA content in tobacco leaves increased first, peaked at 6 hours and then decreased. The increment of JA content in resistant varieties was higher than that in susceptible varieties. The NO content in leaves of aphid resistant varieties increased first, peaked at 3 hours and then decreased. The difference of the NO content in leaves of susceptible varieties was not significant between 3 hours’ aphid feeding and 0 h, but decreased significantly after 6 hours and 9 hours. The CAT activity of all tested tobacco varieties showed an increasing trend at 9 h, and CAT activity of aphid resistant variety ‘Shubalaomuji2113’ increased the most. Therefore, JA and NO contents and CAT activity could be used as physiological indicators for aphid resistance identification in tobacco varieties. The increase of JA content in leaves 5-6 hours after inoculation could be used to identify the resistance of tobacco varieties to aphids.

Bemisia tabaci infection can induce the tobacco resistance to Myzus persicae. The study aims to investigate the relationship between the defense signaling of salicylic acid (SA) and jasmonic acid (JA) and the resistance to Myzus persicae induced by Bemisia tabaci. The effects of Bemisia tabaci nymphs feeding on SA and JA level and downstream defense genes expressing level were tested, and the effects of exogenous SA and JA on the growth and development of Myzus persicae were analyzed by biochemical analysis and real-time fluorescent quantitative PCR. The results showed that Myzus persicae infection obviously activated SA defense pathway. After feeding 15 d, the SA level was 1.40-fold higher than the control, and the levels of PR-1a and PR-2a were increased by 3.22 times and 0.74 times, respectively. JA level was not obviously affected, while the transcript levels of JA downstream defense genes PI-II and TPI were decreased by 73.91% and 56.73%, respectively. Biochemical analysis revealed that the application of exogenous SA was harmful to the survival and the relative average growth rate of M. persicae. Treating with 1 mmol/L SA, aphid survival and growth rate were decreased by 43.2% and 11.54%, respectively, compared with the control. Methyl jasmonate had no harmful effect on the growth and development of Myzus persicae. In conclusion, SA mediated defense response contributes to the tobacco resistance against M. persicae.

The investigation of incidence and prime control?measures of tobacco root rot were made in places?such?as Jiaxian and Baofeng in Pingdingshan tobacco plant areas, in order to solve the problem that the quality and products of tobacco were seriously damaged by tobacco root rot caused by fusarium. The?economic?losses caused by tobacco root rot was also calculated. The control efficacy of EM?microbial agent by different manner such as soil application, watering application and foliar?application was studied took the main mariety Zhongyan 100 as?experimental?material. The soil application study showed that treatment at tilling stage, transplanting stage and earthing-up stage together works best. The morbidity?and?mortality were 23% and 16% respectively. The watering application study showed that treatment at tilling stage, transplanting stage, resettling?stage, fast growing stage and topping stage together works best. The morbidity?and?mortality were 18% and 11% respectively. The foliar?application study showed that there was no significant variation between different treatments and the control. Comprehensive results showed that watering application had a remarkablecontrol effect to tobacco root rot. This results provided some theoretical references for the?biological?control of tobacco root rot.

In view of the single green control bactericide for tobacco angular leaf spot disease, it is urgent to screen out high-efficiency and low-toxicity bactericides for tobacco green control practice. Twelve bactericides with different nature were tested by plate counting method. Six bactericideswith good laboratory bacteriostasis effect were selected for field control evaluation.The results showed that patented bactericide for Chinese Herbal Medicine, 12% zhongshengmycin WP and 2.1% eugenol?carvacrol AS had the best laboratory bacteriostasis effect,the bacteriostasis rate was 100%; Secondly,10 billion Bacillus subtilis WP were produced and 40% zinc thiazole SC, with bacteriostasis rates of 82.84% and 76.14%;The bacteriostasis rate of 6% kasugamycin WP was 63.47%, that of other bactericides was less than 50%, and that of 72% streptomycin sulfate SPX was only 44.1%. Field trials showed that the effects of 10 billion Bacillus subtilis WP, 40% zinc thiazole SC, Chinese herbal bactericide WF, 12% zhongshengmycin WP were from high to low, respectively. The field control effects of the four bactericides ranged from 60% to 65%. these four bactericides can be recommended for green control of Tobacco Angular Leaf Spot Disease.

Root-knot nematode has become the major threat to tobacco in Panzhihua, and caused serious yield loss. To screen biological agent with high efficiency and safety, a field experiment was conducted to determine the effect of four biological agents against tobacco root-knot nematode in Ganbazi, Renhe during 2017-2018. The efficacy was evaluated comprehensively through control efficacy, the correction control efficacy of the decline rate of the second- stage juveniles and the yield- increasing efficiency. The results showed that ‘Yongwei?168’agent gained the highest comprehensive performance with the control efficacy of 62.11%, the correction control efficacy of the decline rate of the second-stage juveniles of 81.05% and the yield increase effect of 53.08% 120 days after the treatment. Therefore,‘Yongwei?168’agent has a good application prospect on controlling tobacco root-knot nematodes.

Tobacco good agricultural practice (GAP) is a set of operational standards which assure tobacco leaf safety and cover entire leaf production process. The core of GAP is hazard analysis and quality control. It also emphasizes environment protection, sustainable development, employee safety and welfare. China tobacco GAP should not only pursue economic efficiency and preserve environment quality, but also take on social responsibility. The basic principles of China tobacco GAP must include assure tobacco leaf quality and safety, protect environment and resources, safeguard employee health and welfare, economically use facilities and promote rural harmonious development.

To catalogue and preserve 23 tobacco germplasm resources collected from Hainan Province, agronomic characters and genetic diversity of these tobacco germplasm resources were investigated, and the fingerprints were constructed. The results showed that the agronomic traits and qualitative traits of tested germplasms varied greatly. The coefficient of variation ranged from 20.69% to 29.41% in different agronomic traits. These collected tobacco germplasms were divided into 3 groups by clustering analysis. The germplasms from the second group were the tallest with the largest leaf, which could be used for high-yield breeding. In addition, 12 pairs of primers with specific amplification were screened from 2000 pairs of SSR primers, and 46 polymorphic bands were obtained. An average of 3.83 alleles was observed for each primer pair with the average heterozygosity (Ho) of 0.5301, and the average expected heterozygosity (He) of 0.4700. Shannon’s index was 0.8930, Nei’s index was 0.4593. The genetic diversity of the 23 tobacco germplasm resources was relatively abundant. These varieties were clustered into two groups at the genetic similarly coefficient of 0.206 by UPGMA cluster analysis. At the same time, 12 pairs of primers were used to construct the fingerprints of the 23 tobacco germplasm resources, which laid a theoretical foundation for the research on the identification system of sun-cured tobacco varieties. The study can provide reference for identification and utilization of sun-cured tobacco germplasm resources and selection of parent materials for cigar breeding.

Pythium was isolated from tobacco stems back rot samples in Song County of Henan Province. In order to know its classification and pathogenicity to tobacco, the morphologic characters that based on microscopy technology were examined and recorded, the rDNA- ITS sequences were analyzed, the pathogenicity tests were conducted. The results showed that the colonies were actinomorphic and gradually grow into petaliform; hyphas were without separate; sporangiums were spherical or pear-shaped; archegoniums were spherical; antheridiums are bell-shaped or irregular. According to the results of the analysis of rDNAITS sequences, the sequence homology was more than 99% when it was compared with the sequence of registration number kc014615.1 and gu133597 in GenBank. Therefore, the pathogen was identified asPythium vexans de Bary. Seedings in ten leaf stage of‘Zhongyan 100’tobacco variety were inoculated withP. vexans de Bary, and the disease symptoms and the disease indexes were surveyed and recorded in the 7th day, the disease index ofPythium vexans was 48 and theP. aphanidermatum was 62.7, the results indicated that the pathogenity ofPythium vexans was less thanP. aphanidermatum.

The paper aims to utilize abandoned tobacco straw and improve its utilization rate effectively, so as to make tobacco plants grow healthier. In this study, the enzyme solution made from the common abandoned tobacco straw in field was used to mix with the screened actinomycetes, Streptomyces griseochromogenes, and the effects of mixed enzyme solution on the growth and development of tobacco seedlings and tobacco plants at seedling and harvest stage were studied. The results showed that: the application of tobacco enzyme solution could increase the yield and quality of tobacco and the ratio of tobacco to superior tobacco; among them, the mixed application of tobacco enzyme solution and S. griseochromogenes had the best effect, which was superior to other treatments and significantly superior to the control. The method of mixing tobacco enzyme solution with antagonistic actinomycetes can be recommended for tobacco production, which not only reduce the accumulation of pathogens caused by abandoned straw in field, but also effectively improve the yield and quality of tobacco.

The achievements about analysis of organic acids in tobacco at home and abroad over past years were reviewed comprehensively, and analyzed the properties and effects of various organic acids, such as volatile, semi-volatile and nonvolatile acids. Pretreatments of samples included solvent extraction, solid phase extraction, stream distillation, etc. Finally, this paper comprehensively introduced analysis of organic acids in tobacco about gas chromatography-mass spectrometry, high performance liquid chromatography (HPLC), ion chromatography (IC) and other methods. It was considered that it was possible to get a good understanding of various elements in smoke as the application and development of this modern separation technology and analysis equipment. And it provided factual basis for perfuming in tobacco industry.

In order to research the early flowering caused by cold in high latitude tobacco field, alginic acid and KH2PO4, both increase cold resistance of plants, are used to spray tobacco leaves to investigate flowering time, leaf quality and quantities. Results showed that alginic acid and KH2PO4 delayed flowering time of tobacco 8 and 5 days, respectively. The total contents of aroma components in flue-cured tobacco leaves are not obviously affected by both treatments. The maximum production is got from alginic acid treated field, and the quantity is 2100 kg/hm2, increase 16.67% than normal field. The medium and fine levels of flue-cured tobacco leaves account for 97.86% of total production, is 3.7 percent higher than normal levels.

In order to figure out the effects of tobacco stubble returning on rice growth and yield, pot experiments were conducted to test the dynamic change of rice tillering, plant height and roots, and the accumulation of dry matter, nitrogen, phosphorus and potassium, and the effects on rice yield by simulating different tobacco stubble returning. The results show that tobacco stubble returning could promote rice tillering, plant height and root development, the accumulation of dry matter, nitrogen, phosphorus and potassium, and rice yield. The tobacco stubble total returning and the tobacco root returning could increase the yield by 17.35% and 8.60%, respectively. Tobacco stubble total returning is beneficial to the growth and yield of rice, and it can be popularized in tobacco rice multiple cropping area.

To understand the inhibition mechanism of alginate to tobacco mosaic virus (TMV), the in vitro inactivation and systemic resistance induction were investigated in tobacco treated with alginate. The results showed that, after spraying alginate, the lesion inhibition rate reached 66.67%, proliferation inhibition rate reached 34.67%, the expression level of N gene increased to 2.67 times of the control levels, POD activity increased to 3.46 times, SOD activity increased to 1.43 times of the control levels. Therefore, proliferation inhibition of alginate to TMV might be caused via the increase of disease-resistance and oxidation resistance abilities.

To clarify the decomposition characteristics of tobacco residues returning to field and the effect on the nicotine content in soil and rice plants, pot experiments were used to study the decomposition characteristics of tobacco stems and roots, and the dynamic changes of soil pH, organic matter and nutrients and nicotine. The results showed that: (1) the decomposing rate and nutrient release of tobacco roots and stems were both fast in the early stage and slow in the later stage, the cumulative release rate of each nutrient was nitrogen (N) > phosphorous (P)> potassium (K), the decomposing rate and nutrient release of tobacco roots were both slower than those of tobacco stems; after tobacco residues returning to field for 120 days, the cumulative decomposing rate of tobacco roots and stems was 45.02% and 53.82%, respectively; (2) returning tobacco stems and roots to field could increase the soil organic matter content by 9.35%-39.87%, the soil pH would decrease at the beginning, but increase after 90 days; (3) nicotine was released fast from tobacco residues, after tobacco residues returning to field for 5 days, about 50% of nicotine was released, and the nicotine in the tobacco residues was basically released after 40 days; nicotine from tobacco roots was released faster than that of tobacco stems, after 30 days, the cumulative nicotine release rate of tobacco roots and stems was 96.95% and 94.03%, respectively, and the nicotine content of each treatment soil was 0 μg/g after 90 days; rice plants absorbed trace amount of nicotine in the early stage, but the content of nicotine in the rice plants was 0 μg/g after 20 days. Overall, returning tobacco residues to field could improve soil nutrients, and there will be no nicotine residue in soil and rice plants in the later stage.

Bacterial manure as an important biological control approach, was widely used in crop production. This study was conducted to evaluate the effect of two bacterial manures, Effective Microorganisms (EM) and Bacillus mucilaginosus, with different treatments (5 %, 10 % and 15 %) and their combination on the seed germination rate and seedling growth of Honghuadajinyuan and Yunyan 85. The results showed as follows: Adding EM and Bacillus mucilaginosus in seedbed could improve the germination rate of two tobacco seeds. The effect of promote germination to the two tobacco seeds was mainly reflected in the post-germination stage (in 17 ~ 19d) when adding one bacterial fertilizer. Promotion effect was feflected in whole germination stage of Honghuadajinyuan when two bacterial fertilizer as co-addition, while slightly inhibition was mainly reflected of Yunyan 85 in the initial germination stage, the germination rate was higher than the control at 21 d. The treatments of bacterial manures improved the growth of main root and lateral root of Honghuadajinyuan and Yunyan 85 at three leaf period, the promotion of low concentration (5 %) to two tobacco seedings was remarkable when adding EM only. While the promotion effect of middle concentration (10 %) was notable when adding Bacillus mucilaginosus only. The argonomic characteristics also could be improved with the combination of two bacterial fertilizer in three leaf period. The application of EM and Bacillus mucilaginosus promoted the growth of root, the total number of root so as to modify the growth status at five leaf period. The plant height, stem diameter ,longest leaf length and maximum leaf width of two tobacco seedlings were also improved with bacterial manures at 70 d after treated(before transplanting). To sum up, adding EM and Bacillus mucilaginosus in seedbed could improve germination rate and seedling growth of tobacco in different extent, especially adding 5 ~ 10 %.

To understand the mechanism of boron transportation in tobacco, the boron influx transporter gene was cloned in Nicotiana tabaccum, and its expression was analyzed. The open reading frame (ORF) of boron influx transporter was predicted by biology informatics methods, and cloned by PCR technique, verified by sequencing. Its structure was also predicted by biology informatics methods. Semi-quantitative RT-PCR was used to monitor its expression levels in different tissues of tobacco with different treatments. Results showed that the complete ORF sequence of tobacco influx boron transporter, NtNIP5;1 was cloned. Its ORF contains 894 bp, encodes 297 amino acids and includes MIP protein signature sequence HLNPSLTIA. GenBank accession number is KF611892. Its protein consists of α-helix mainly in secondary structure, and was composed of five transmembrane domains. Results of RT-PCR showed that NtNIP5;1 were expressed in roots and leaves, and showed higher levels in leaves. Its expression was inhibited by 6-BA, SA and ABA.

Nitrogen is the necessary nutrient for the growth and development of tobacco. It has a certain influence on the chemical process of tobacco, such as chemical synthesis, energy conversion and signal transmission. Ammonium nitrogen and nitrate nitrogen are the main nitrogen forms of tobacco absorption, which have different effects on different parts of tobacco and different parts. The reasonable ratio of nitrogen is beneficial to the uptake of nitrogen and the improvement of tobacco leaf quality. In this paper, the effects of different nitrogen forms on the growth and development, growth, element absorption, photosynthetic characteristics and carbon and nitrogen metabolism of tobacco were reviewed. The effects of different nitrogen forms on the growth and development of tobacco were studied. Influence the relevant research to provide the basis.

A pot experiment was conducted to study the effect of ree fertilizer on growth and development of tobacco and its preventive effect on Cd uptake by adding exogenous Cd to soil. The results showed that Cd stress inhibited the growth and development of tobacco, decreased the uptake of nitrogen, phosphorus, potassium, calcium, magnesium and zinc, but promoted the uptake of copper. When the application amount of ree fertilizer was 0.4 g per kilogram soil (900 kg/hm²), the inhibition effect of Cd stress on the growth and development and nutrient absorption of tobacco were relieved, and Cd concentration in tobacco leaves decreased. When the Cd added concentration was 1.2 mg/kg, Cd concentration in middle-lower leaves decreased by 19.7% compared with that of CK. When the application amount of ree fertilizer was 0.4 g per kilogram soil (without adding exogenous Cd), the uptake of cadmium, zinc and copper decreased and the uptake of potassium increased, the contents of Cd in the upper and middle-lower leaves decreased by 23.4% and 7.84%, respectively, but the contents of potassium increased by 14.1% and 9.51%, respectively, compared with that of CK. The distribution of Cd in tobacco was middle-lower leaves＞upper leaves＞stalk.

An ion chromatographic method for the determination of potassium, sodium, calcium, magnesium and ammonia in tobacco was developed. The potassium, sodium, calcium, magnesium and ammonia were extracted from the samples by ultrasonic extraction with 5% hydrochloric acid solution in an extraction bottle with solid phase extraction and purification function, and the extract were purified by solid phase extraction with graphitized carbon black. The purified samples were separated on an IonPacCS12A (3?150 mm，5 μm) cation ion exchange column with 30 mM methanesulfonic acid as mobile phase. The five cation ion (K+、Na+、Mg2+、Ca2+、and NH4+) were separated within 5.0 min. The sample extraction, purification, and filter can be completeed in our self-designed extraction bottle without any sample transfer. Compared with the conventional method, the operation process is simplified and the efficiency is greatly improved in new method. In addition, the new method has high sensitivity and high recovery, and provides a high-throughput analysis method for the rapid determination of potassium, sodium, calcium, magnesium and ammonia in gene editing materials.

The effect of different mulching types on soil environment and growth of flue-cured tobacco was studied by field experiment. The no coverage, ordinary film mulching, three-dimensional film covering and straw mulching were carried out to clarify their ecological effect in tobacco field. The results showed that the soil temperature of different soil layers under different mulching types had similar trend, and the soil temperature decreased with the increase of soil depth, and the temperature changes of different soil layers under the same mulch type were consistent. The heat insulation effect of ordinary film mulching on soil temperature was the best, which could promote tobacco seedlings to grow quickly and early, but the high surface temperature at the rosette stage under mulching might affect the root growth. The effect of straw mulching on soil temperature during the growth period was relatively good, and the soil temperature of three-dimensional covering was the lowest of all during the early growth of flue-cured tobacco. Ordinary film mulching was not conducive to absorption the atmospheric rainfall into ridge soil, its soil water content was the lowest, meanwhile, it could avoid the soil nutrient leaching. Straw mulching had the best effect on soil moisture storage, followed by three-dimensional film covering. The ordinary film mulching was the most conducive to the growth of flue-cured tobacco at the rosette stage, followed by the straw mulching, and then the three-dimensional covering. The worst tobacco growth was found in the non-mulching treatment. And the straw mulching treatment had the highest root shoot ratio among all treatments. The results indicate that the effect of three-dimensional mulching on soil temperature and humidity and the growth and development of flue-cured tobacco at rosette stage is lower than that of ordinary film mulching. Further research should be carried out on the whole growth and development period of flue-cured tobacco, the characteristics of yield and quality, and the cost-benefit and environmental impact of mulching.

Tomato spotted wilt virus (TSWV) and potato virus Y (PVY) are the main virus diseases of tobacco in Yunnan, the research aims to screen highly effective agents to control the virus on tobacco, thereby reducing the economic losses of tobacco. Through field plot tests, the control effects of 1% lentinan aqueous solution, 3% harpin protein, 5% amino oligosaccharide water and 2% cytosintetidemycin on TSWV and PVY were investigated. The results showed that the four agents had certain preventing and control effects on TSWV and PVY. The control effect of 1% lentinan aqueous solution, 3% harpin protein, 5% amino oligosaccharide water and 2% cytosintetidemycin was 31.11%-39.90%, 54.34%-59.91%, 8.69%-38.21% and 22.75%-43.32% on TSWV, respectively, and 55.08%-71.06%, 68.10%-82.24%, 37.76%-55.36% and 58.07%-68.86% on PVY, respectively. Among them, the control effect of 3% harpin protein was the best, which was over 50% and 60% on TSWV and PVY, respectively, followed by that of 2% cytosintetidemycin, which was over 22% and 58% on TSWV and PVY, respectively.

To provide biocontrol microbial resources for the prevention and control of tobacco rhizome diseases, biocontrol strains with good control efficacy on Ralstonia solanacearum and Phytophthora parasitica were screened. The bacteria strains were isolated from the rhizosphere soil of the diseased tobacco plants, and the inhibitory activity was determined by plate face-off method and filter method. The control efficacy of highly active strains was further detected by pot tests. Molecular biological identification of the highly active strains was carried out by 16S rDNA. The promoting and antibacterial activities of the strains were verified by PCR using 9 pairs of specific primers. Two highly active strains LF-1 and LF-2 were obtained and identified as Bacillus subtilis and Bacillus amyloliquefaciens. The results of activity test showed that the inhibition rate of the two strains was 31.16% and 56.98% on R. solanacearum, and 64.44% and 72.44% on P. parasitica, respectively. The corresponding potted experiment showed that the inhibition rate of the two strains was 69.54% and 72.49% on R. solanacearum, and 65.49% and 68.32% on P. parasitica, respectively. The two strains had good control effect on tobacco rhizome diseases and broad application prospect in tobacco disease control.

Tobacco is one of the important economic crops in China. The tobacco pest species have reached more than 300 in China, which severely restrict the production of tobacco. Plant insect resistance is the most cost-effective means to control pests. To better understand current researches on tobacco resistance to pest at home and abroad, this review summarized basic composition of tobacco resistance to pests and induced chemical defense, signal pathways and molecular mechanisms. It was suggested that the main pests on tobacco had been transformed from the Lepidoptera pests to the sucking pests. However, the researches on tobacco insect resistance and resistance breeding aimed at single pest at home and abroad. Therefore, the study on comprehensive resistance to different pests and the breeding of multi- resistant varieties should be strengthened. At the same time, it was pointed out that photosynthesis was a systematic reaction of plant defense against insects. In the process of improving the tobacco resistance to insect and tobacco resistance breeding, the primary metabolic process of tobacco, especially photosynthesis, should also be the focus. Study on tobacco resistance to insects should be carried out with multi-disciplinary combination, to elaborate the issue from a number of perspectives, especially plant physiology, molecular biology, tobacco cultivation and tobacco breeding.

To screen out the effective fungicides to control tobacco bacterial wilt caused by Ralstonia solanacearum, the toxicity of five fungicides, including streptomycin sulfate, ethylallicin, octyllamine acetate, Kejunkang and Qingkuling, to tobacco bacterial wilt bacteria was determined with plate inhibition zone method while their efficacy was tested by pot experiment in greenhouse by inoculating pathogen first and then irrigating drugs. The results showed that the five fungicides could inhibit the growth of tobacco bacterial wilt. There was a significant positive correlation between the concentration of fungicides and the inhibition effect. The correlation between the concentration of fungicides and the inhibition effect was significant. The EC₅₀ of 72% Streptomycin sulphate, 80% ethylallicin, 1.8% octyllamine acetate, 3% Kejunkang and 50% Qingkuling was 43.50, 154.69, 116.75, 123.43 and 37.86 mg/L, respectively. Pot experiment showed that 50% Qingkuling had the highest inhibition rate against tobacco bacterial wilt, with the control efficacy of 88.6%; followed by 72% streptomycin sulfate, with the control efficacy of 79.6%. 1.8% octyllamine acetate, 80% ethylallicin and 3% Kejunkang had poor control effects on tobacco bacterial wilt with control efficacy of 75.6%, 56.7% and 52.3%, respectively.