Search

【Objective】The soil environment of tobacco planting can be impacted by plastic film mulching, which affects the structure of the soil microbial community and the growth and development of flue-cured tobacco. The purpose of this study is to investigate the effect of a full growth period mulching on the physicochemical properties and bacterial community structure of tobacco planting soil.【Method】16S rDNA sequencing was applied to compare the differences in the structure and diversity of bacterial communities in different treatments by various analytical methods. The connection between soil physicochemical properties and bacterial communities was discovered through redundancy analysis (RDA) based on soil physicochemical properties.【Result】The output value of flue-cured tobacco was significantly increased by film mulching during the growth period. The yield was increased by 13.33%, 18.24%, and 21.36% by the double color film mulching (SY), black film mulching (HY), and white film mulching (BY) treatments, respectively, compared to the control (CK); Output value added was 20.26%, 15.87%, and 13.28%. At the same time, film mulching will also increase tobacco-planting soil temperature, total potassium, total phosphorus, total iron and effective copper contents, and decrease soil pH value, alkaline dissolved nitrogen, effective iron, total copper and total zinc contents. The contents of total phosphorus and available copper increased the most significantly, reaching 3.11%-27.33% and 4.76%-19.05%, respectively. The most significant decrease in alkali hydrolyzed nitrogen, available iron, and total zinc occurred at 10.45%-14.50%, 3.36%-13.43%, and 7.69%-10.01%, respectively. Plastic covering during the whole growth period has a certain negative impact on the abundance of bacterial communities. The abundance index Chao 1 of the control was significantly higher than the three mulching treatments and was 14.09%, 24.20%, and 24.81% higher than that of the white film mulching, double color film mulching, and black film mulching treatments, respectively. Redundancy analysis shows that the main soil physicochemical factors affecting the horizontal community structure of the bacterial phylum are soil temperature, alkaline nitrogen, available iron, total iron, available copper, and total copper content. Three shared genera with significantly different abundance from the control were present in the white film mulching and double color film mulching treatments, which belonged to three families in the phylum Proteobacteria: Sphingomonadaceae, Burkholderiaceae, and Xanthomonadaceae.【Conclusion】The full-life stage mulching cultivation will significantly affect the physicochemical properties and bacterial community structure of tobacco-planting soil, and improve the amount of output value of roasted tobacco, suitable for matching the color of the film is black and white bicolor film. [ABSTRACT FROM AUTHOR]

[Objective] To explore the potassium chloride application measures suitable for Luzhou tobacco planting area and further improve the regulation technology of upper tobacco leaves in the field. [Method] A field experiment was conducted with Zhongchuan 208' as the test material. Four potassium chloride application rates of 30,60,90 and 0 kg/hm² were set. The ratio of base fertilizer to topdressing was 5: 5. The topdressing period was set at 30 and 50 d after transplanting, with a total of seven potassium chloride application methods. The changes of agronomic characters, SPAD value, economic characters, chemical composition and physical characters of upper tobacco leaves were analyzed. [Result] Compared with no application of potassium chloride, the application of potassium chloride increased the yield, output value, average price and the proportion of medium and high-grade tobacco by 3.11%-9.17%,6.12%-19.29%, 2.79%-12.92% and 4.01%-18.25% respectively. The color, maturity, body, oil content and chroma of flue-cured tobacco were improved, and the comprehensive score was increased by 1.15%8.30%. [Conclusion] Applying 30 kg/hm² potassium chloride as base fertilizer and applying 30 kg/hm² after transplanting for 50 days has the highest economic benefit. The appearance quality, chemical composition and physical properties of the upper tobacco leaves after baking get the highest score. [ABSTRACT FROM AUTHOR]

The genus Nicotiana is an important germplasm source for cultivated tobacco varieties improvement, the creation of tobacco interspecific hybrids and their molecular cytological analysis during the meiotic phase will provide the basis for the subsequent efficient transfer and utilization of excellent wild germplasm. Allotriploid interspecific hybrids were created from the parents of Nicotiana sylvestris Q67 and common Nicotiana tabacum L. cv. K326. Their chromosome composition, chromosomal behavior during the meiosis and expression of related genes were investigated by routine cytological observation, genomic in situ hybridization and real-time quantitative PCR. In this study, 68 allotriploid hybrids (SST) with 36 chromosomes were identified by phenotypic and cytological analysis from crossing Nicotiana sylvestris with Nicotiana tabacum. The results of general cytology and genomic in situ hybridization showed that 29.26% of the pollen mother cells of interspecific hybrids were abnormal in meiosis. The main abnormal behavior was the backward chromosomes from the T chromosome group in metaphase I and II, with 1-3 lagging chromosomes. The cells with the most lagging types in metaphase I and II were the cells with 1 and 2 lagging T chromosomes respectively. They accounted for 29.09% and 30.88% of the total number of cells carrying backward chromosomes, respectively. The abnormal types of anaphase I, anaphase II and telophase II were mainly unequal segregation, backward chromosomes and micronucleus. In anaphase I, a variety of abnormal segregation ratios were counted, but the chromosome composition after segregation was still close to 2∶1 (S∶T). The results of RT-qPCR showed that in prophase I, except for the significant up-regulation of CDKA:5319 and CYCA:6720 from S chromosome group, the expressions of other genes were significantly down regulated. From the metaphase I to the telophase II, compared with the control, except that MIS12 and CDKA:0239 from T chromosome group had no significant changes, other genes（CENH3, CDKA:5319, CYCA:0111 and CYCA:6720）were significantly or extremely significantly up-regulated, indicating that the disorder expression of meiosis related genes may be causing the abnormality of meiosis. [ABSTRACT FROM AUTHOR]

【Objective】To solve the problem of large differences in the maturity status of the upper leaves of flue-cured tobacco at one-time harvest, the present experiment explored the effects of gibberellin and potassium nitrate spraying concentration and spraying time on the simultaneous maturation and flue-cured tobacco quality of the upper 6 tobacco leaves of the flue-cured tobacco Zhongchuan 208. The impact was expected to provide a theoretical basis for promoting the one-time harvest of flue-cured tobacco. 【Method】Using the Box-Behnken method in response surface optimization design, the concentration of gibberellin (0, 15, 30 μmol/L) and potassium nitrate (0, 0.5, 1.0 g/L) and the spraying time (20, 25, 30 days) after topping was designed with three factors and three levels, a total of 16 treatments. The physiological indicators related to the maturation of the 1-3 tobacco leaves from top to bottom(denoted as Tup) and the 4-6 tobacco leaves from top to bottom(denoted as Tdown) were measured, and the treatment indexes were calculated. The synchronization maturity value was used as a basis for measuring synchronization maturity. The smaller the value, the better the synchronization maturity state. 【Result】 The synchronous maturity value of each treatment was significantly lower than that of the control, and the appearance quality and total chemical composition of cured tobacco leaf were higher than that of the control. The treatment of spraying 15 μmol/L gibberellin and 0.5 g/L potassium nitrate (T2, T5, T9, T16) had the best synchronous mature state, and the highest total score of appearance quality and chemical composition; The results of response surface showed that gibberellin and potassium nitrate had a very significant impact on the comprehensive score, and the impact curve was similar. The spraying time also had a very significant impact on the comprehensive score. The model validation and optimization results showed that the comprehensive score of flue-cured tobacco was close to the predicted value, indicating that the model was reliable and could predict the comprehensive score of flue-cured tobacco.【Conclusion】Spraying gibberellin and potassium nitrate can promote the uniform maturity of upper leaves and improve the quality of flue-cured tobacco leaves. [ABSTRACT FROM AUTHOR]

【Objective】This paper aimed to explore the effect of green manure tillage instead of chemical fertilizer on the improvement of tobacco planting and tobacco leaf production in Yibin area and selected the most suitable green manure varieties.【Method】In this experiment,a community experiment was carried out to study the effects of three kinds of green manure substitute fertilizers,such as rape,light purple scorpion and arrow pea,on the agronomic traits and quality of flue-cured tobacco in Yibin area.【Result】(i) The replacement of chemical fertilizer with green manure could promote the agronomic traits of tobacco plants at different growth stages,and the plant height,maximum leaf length and maximum leaf width increased significantly by 14.04 %-19.29 %,5.79 %-14.86 % and 3.72 %-19.14 %,respectively; The plant height and effective leaf number in the long-term growth period increased significantly by 7.52 %-23.67 % and 3.45 %-5.91 %,and the plant height in the topping stage increased significantly by 2.15 % to 6.13 %,of which T1(canola green manure) the treatment of agronomic traits of tobacco plants was most significant;(ii) The replacement of chemical fertilizers with green manure could promoted the increase of the output value of flue-cured tobacco.The treatment with T1(canola green manure) was the most significant,but the overpressure might cause the late fallacy caused by greed,and yellow was late,which reduced economic benefits.(iii) Different green manure types had different effects on the chemical constituents of flue-cured tobacco in the middle of flue-cured tobacco.T1(canola green manure) treatment significantly increased the total nitrogen and nicotine content in the middle leaves; T2(light-leaf alfalfa) treatment on the middle The reduction of leaf reducing sugar,total sugar and total nitrogen was more significant; T3(Arachis chinensis) treatment significantly increased the K content in the middle tobacco leaves.【Conclusion】The overall replacement of chemical fertilizers with different green manure types could enhance the chemical content of tobacco leaves and improve coordination. [ABSTRACT FROM AUTHOR]