The aim was to explore the regulation mechanism of different coupling ratio of irrigation and nitrogen fertilizer application on photosynthesis, transpiration rate, chlorophyll value, dry matter accumulation characteristic and yield of maize. In this research, using the corn variety of ‘Yuyu 22’ as research material, a split plot design field experiment was carried out in dryland areas of Gansu Province in 2022. Three irrigation application amount treatments of 3150 m3/hm2 (W1), 3825 m3/hm2 (W2) and 4500 m3/hm2 (W3) were set as the main plot, and three nitrogen application amount treatments of 0 (N0), 272 kg/hm2 (N1) and 320 kg/hm2 (N2) were set as the split plot. Photosynthetic rate, transpiration rate, chlorophyll value, dry matter accumulation characteristic and yield at the growth period of maize were determined. The results showed that under a reduction of 15% in irrigation amount during growth, compared with the W2N0 and W2N2 treatments, the photosynthetic rate, transpiration rate and chlorophyll value under the W2N1 treatment were increased by 30.91%, 13.53% and 39.78%, 26.46% and 32.33%, 9.21%, respectively. The maximum growth rate of dry matter in W2N1 treatment was 7.5 and 3.7 days later than that in W2N0 and W2N2 treatments, respectively. The Vmax of W2N1 treatment was 11.25% and 4.24% higher than that of W2N0 and W2N2 treatment, respectively. Compared with W2N0 and W2N2 treatments, the biological yield and grain yield of maize with the W2N1 treatment were increased by 29.97%, 5.15% and 48.61%, 10.78%, respectively. The conclusion showed that the treatment with application coupling of irrigation and nitrogen (i.e. reduction of 15% irrigation amount during growth with 3825 m3/hm2 and reduction of 15% N application amount with 272 kg/hm2 at growth stage) could be considered as the best cultivation pattern management, which could provide technical guidance for further exploring for water-saving and fertilizer-saving and high yield and efficient cultivation of agriculture in the dryland areas.
To solve the problem of low potassium content in tobacco leaves caused by high soil pH and rich calcium ion content in slightly alkaline soil, the pot and field experiments were carried out to study the effects of different dosage and combination of oxalic acid, citric acid and sulfur powder on soil pH value, available potassium, available calcium content, chemical indexes and yield of flue-cured tobacco. The results showed that: (1) all acidic substances and their combinations could reduce soil pH within a certain range. In terms of improving soil available potassium content and tobacco yield and quality, citric acid and ztric acid + sulfur had significant effects. It had been preliminarily established as an acidic substance suitable for improving slightly alkaline soil. (2) After the application of acidic substances, it could effectively reduce the pH and exchangeable calcium ion content of rhizosphere soil, and improve the content of available potassium in soil. The T4 (citric acid 4 g/plant + sulphur powder 11 g/plant) and T2 (citric acid 15 g/plant) had better treatment effects. (3) After the application of acid substances, the yield of tobacco leaves was significantly increased, ranked as followed: T4>T3>T5>T2>T1>T0, and there were significant difference between T3, T4, T5 and T0, with an increase of 65-260 kg/hm2 compared to T0. (4) After the application of acid substances, the internal quality of tobacco leaves was effectively improved. The comprehensive index of chemical composition was 0.66-0.87, which was 8.19%-60.78% higher than that without the application of acidic substances. (5) Compared with not applying acidic substances, the potassium content of middle and upper leaves increased by 24.3% and 20.3% respectively. Citric acid 4 g/plant + sulfur powder 11 g/plant and citric acid 15 g/plant were suitable formulas for improving slightly alkaline soil. They can effectively reduce soil pH and exchangeable calcium content, increase tobacco yield and potassium content, and improve the intrinsic quality of tobacco leaves.
To understand the research progress of colored rice and its related genes, the functions of colored rice were summarized, and the effects of Ra, Rc, Rd, OsC1 and OsB2 genes on the traits of colored rice were analyzed. These genes determine the red, black, and purple colors of rice grains by influencing the accumulation of anthocyanins and proanthocyanidins. In this paper, we point out the limitations of related rice color genes in rice breeding. And the current research is not systematic enough to make full use of the diversity of these genes and prove the role of these genes in other rice traits. It is believed that genome-wide association analysis and population genetics method can be used to systematically analyze the variation and expression patterns of these genes in different rice varieties, and provide data support for rice genetic improvement. We can also use genetic methods and modern biotechnology methods to explore the functions of these genes in other traits of rice, to provide theoretical basis for the improvement of multiple traits of rice.
In order to carry out pear variety resource identification work more scientifically, quickly and accurately, the article reviewed the SSR fingerprinting ID technology, the research progress and application of this technology in pear variety identification, and analyzed in detail the current problems of this technology in terms of simplicity, expandability, and collection and analysis of tagged data, etc. To address the above problems, the article introduced the direction of improvement such as using more efficient coding methods, data expansion, and fluorescent labelling capillary electrophoresis detection technology, etc. The article also looked forward to the future of SSR fingerprint ID technology combined with the new generation of sequencing technology, to achieve faster, more accurate and more efficient identification of pear varieties.
In order to investigate the effects of water stress on the morphology and structure of cucumber root system and its response mechanism to water stress, we selected the cucumber variety ‘Xinchun 4’ as the test material for a pot experiment. Four treatments, namely, normal water supply (CK), mild stress (T1), moderate stress (T2), and severe stress (T3), were set to study the effects of different levels of water stress on the root architecture, antioxidant enzymes and osmotic regulating substances of the cucumber root system. The results showed that the plant height, stem thickness and leaf area of cucumber seedlings did not decrease under T1 treatment compared with normal water supply, while T2 and T3 treatments showed strong inhibition of cucumber growth and development, and T1 treatment increased the total length, total surface area, total mean diameter and number of root tips of the cucumber root system by 10.6%, 29.2%, 8.9% and 10.4%, respectively. In terms of root physiological activities, root vigor, SOD, POD and CAT activities, as well as MDA content and proline content tended to increase with the increase of water stress, while root soluble protein content tended to decrease with the increase of water stress. In conclusion, it can be seen that under mild water stress, the root system of cucumber seedlings can improve its adaptive ability to water stress by regulating the activities of antioxidant enzymes, osmoregulatory substances and soluble protein concentration, in order to maintain its normal physiological and metabolic functions.
To study the effects of different application methods and concentrations of silicon fertilizer on the quality of plum ‘Qingcui’, plum ‘Qingcui’ was used as the test material, and silicon fertilizer was applied through root irrigation and foliar spraying. The results indicate that different application methods and concentrations of silicon fertilizer can significantly improve the appearance quality, such as single fruit weight, as well as the intrinsic quality indicators like soluble solids content, total sugar, total acid, and vitamin C in plum ‘Qingcui’. After flowering and during the fruit swelling period, spraying a 600-fold diluted solution of silicon fertilizer on the leaves is most effective. Irrigating the roots with 0.35 kg per plant before budding, after flowering, and during the fruit swelling period is the second most effective method. Foliar application can more directly provide the necessary silicon elements to the fruit, promoting its development and quality improvement.
To investigate the impact of rachis smearing treatment in different concentrations of GA3 (gibberellic acid) on the fruit quality of five domestic self-bred grape varieties, and to determine the optimal GA3 concentration for each variety, an experiment was conducted to provide practical guidance for practical production. The five grape varieties were ‘SP522’, ‘Huozhou Heiyu’, ‘Gebi Xinxiu’, ‘Wuhe Cuibao’, and ‘Ruidu Cuixia’. Rachis of these grapes were smeared in petroleum jelly containing 0 mg/L (control), 0.5 mg/L, 2 mg/L, and 5 mg/L of GA3. The results showed that under the 0.5 mg/L GA3 treatment, the appearance quality indicators, cluster weight, and berry weight of ‘SP522’, ‘Huozhou Heiyu’ and ‘Wuhe Cuibao’ grapes were significantly higher than those of the control (CK) and other treatments. When treated with 2 mg/L GA3, the tensile strength and hardness of ‘SP522’, ‘Huozhou Heiyu’ and ‘Ruidu Cuixia’ grapes reached their maximum values. The cluster weight of ‘Gebi Xinxiu’ and ‘Ruidu Cuixia’ grapes increased under the 5 mg/L GA3 treatment, and the solid-to-acid ratio of ‘SP522’, ‘Wuhe Cuibao’, and ‘Ruidu Cuixia’ grapes was higher than control and other treatments. Notably, under the 5 mg/L GA3 treatment, the fruit cracking rate of ‘Wuhe Cuibao’ grapes decreased by 37.38% compared to the control after soaking for 24 hours, and the tensile strength and hardness of ‘Gebi Xinxiu’ grapes reached their maximum.
In order to solve the negative influence of weak light in solar greenhouse on the yield and quality of strawberry in winter and spring in northern China, the supplementary light was set inside the greenhouse [supplementary light intensity was (20±3) μmol/(m2·s), supplementary light duration was 3 h/d, T1] for strawberries, and no supplementary light treatment was set as control (CK). The results showed that the supplementary light treatment significantly promoted the increase of plant height and photosynthetic pigment content in strawberry leaves, and the chlorophyll a content, chlorophyll b content, total chlorophyll content, and carotenoid content in strawberry leaves increased by 27.3%, 35.9%, 21.7%, and 19.4%, respectively. Absorption flux per reaction center (ABS/RC), trapped energy flux per RC (TR0/RC) and dissipation energy flux per RC (DI0/RC) decreased by 13.5%, 7.6%, and 20.0%, respectively, which indicated that the pigment unit of strawberry leaf antenna absorbed and captured less light energy, resulting in less light energy for electron transport. Compared with strawberry plants grown without supplementary light, the energy loss of photochemical reaction in strawberry leaves was significantly reduced by supplementary light. The contents of soluble protein, soluble sugar, and vitamin C in strawberry fruit treated with supplementary light increased by 56.1%, 6.8%, and 3.1%, respectively, compared with those treated without supplementary light. In terms of the influences of volatile substances, the nitrogen oxides, alkanes, sulphide, alcohols and aromatic compounds, alkanes and aliphatic groups increased by 15.3%, 16.2%, 10.6%, 6.8%, and 6.7%, respectively, compared with the no supplementary light treatment. In conclusion, solar greenhouse supplementary light treatment significantly promoted the growth of strawberry plants, the improvement of strawberry fruit quality and the accumulation of flavor substances.
The ornamental traits of 50 kinds of garden chrysanthemum were comprehensively evaluated and screened to provide data support for the screening of excellent varieties in cool areas such as Ningxia. The hierarchical analysis method was used to establish a hierarchical structure model, and the judgment matrix was constructed to observe and count the flower color, flower diameter, flower number, group flowering period, plant height, plant height, branch number, stem thickness, leaf color, disease, leaf length, leaf width and crown amplitude of 50 species of garden chrysanthemum. According to the total ranking of the hierarchy, the comprehensive scores of the main trait differences, weight value and ornamental traits were calculated. The number of flowers, crown amplitude, group flowering period and number of branches (ranking value> 0.1) were the four main factors restricting the ornamental value of chrysanthemum. 20% of the varieties with excellent ornamental value were selected, among which ‘Jiangyue’ was the best; 56% of the varieties were good, with ‘Deep Yellow Night Cat’ being the best; the general varieties accounted for 24%, with ‘Ninghong’ being the best.
In order to study the most suitable matrix composition for different cultivars of Bougainvillea spectabilis, the current-year and healthy ‘Yunnan Purple’, ‘Greenery Orange’, ‘Chaozhou Red’, ‘Leaflet Purple’, ‘Snow White’ and ‘California Yellow’ were selected as experimental materials to measure the ground diameter, main stem increment, longest branch increment, biomass, chlorophyll content and photosynthetic parameters. The results showed that the ground diameter increment, main stem increment, chlorophyll content, leaf biomass and photosynthetic parameters of different Bougainvillea varieties had significantly different variation trends under different substrate treatments. ‘Chaozhou Red’, ‘Leaflet Purple’ and ‘Greenery Orange’ under the garden soil: peat soil: perlite (1:1:1) substrate treatment showed a higher trunk length increase; the highest value of the ‘Greenery Orange’ on leaf biomass was under the garden soil: peat soil: chaff (1:1:1). The highest value of leaf biomass of ‘Greenery Orange’ appeared in the matrix treatment of garden soil: peat soil: rice husk (1:1:1). In addition, ‘Chaozhou Red’ and ‘Leaflet Purple’ showed higher stem biomass when treated with garden soil: peat soil: perlite (1:1:1). The chlorophyll a content of ‘Yunnan Purple’, ‘Chaozhou Red’, ‘Leaflet Purple’, ‘Snow White’ and ‘Greenery Orange’ showed the highest value in pure peat soil, and the change trend of chlorophyll b was similar to that of chlorophyll a. The net photosynthetic rate (Pn) of ‘Chaozhou Red’ and ‘Yunnan Purple’ had the highest value when garden soil: peat soil: rice husk (1:1:1). Therefore, there are great differences in the most suitable substrate composition among different cultivars of Bougainvillea spectabilis, ‘Chaozhou Red’, ‘Leaflet Purple’, ‘Snow White’ and ‘California Yellow’ are suitable for substrate composition of pure garden soil or garden soil: peat (1:1); ‘Yunnan Purple’ and ‘Greenery Orange’ are suitable for garden soil: peat soil: perlite (1:1:1) or garden soil: peat soil: chaff (1:1:1) matrix.
In order to further understand the genetic diversity of Syringa germplasm resources, using 118 germplasm resources of Syringa as experimental materials, and 9 quantitative traits and 28 qualitative traits were measured. The genetic diversity of phenotypic traits of Syringa germplasm resources were studied by diversity analysis, correlation analysis, cluster analysis and principal component analysis. The results showed that a total of 81 variant types were observed for the 28 qualitative traits. Among them, shape of lobe, color of new shoots and shape of inflorescence had a large variation range. The Shannon-Wiener information index H' and genetic diversity index D of 28 qualitative traits respectively varied from 0 to 1.63 and 0 to 0.79. And the higher diversity indexes were observed in shape of lobe (H'=163, D=0.79) and color of new shoots (H'=1.23, D=0.67). The lowest coefficient of variation of leaf shape index was 15.78% in 9 quantitative traits and the highest coefficient of variation of length of inflorescence was 37.95%. Bud diameter was significantly correlated with bud length, leaf length and leaf width, the correlation coefficients were 0.748 and 0.833 (Sig.<0.01). The 118 Syringa germplasm resources were divided into 3 groups at the Euclidean distance of about 15 according to cluster analysis; the first group could be used for selecting large flower diameter and tightly inflorescence cultivars; group II could be used for selecting loose inflorescence cultivars; and group III could be used for selecting large inflorescence cultivars. Principal component analysis results showed that the cumulative contribution rate of the first four principal components reached to 73.885%. The samples based on the first two principal components value were selected as the preferred traits form the higher contribution traits, and the floret size factor and leaf size index were selected for correlation evaluation, which could improve the efficiency for evaluation and breeding selection of Syringa germplasm.
The microbial composition and function in the rhizosphere is the research focus of microbial ecology. Analysis of the diversity of soil microbial communities in the root system of paddy rice and the effects of environmental factors on soil microorganisms can provide reference value for the sustainability of soils in the growing areas of paddy rice and the conservation of land resources. In this study, we used 16S rRNA high-throughput sequencing technology to determine the bacterial composition of soil microorganisms in the rhizosphere of paddy rice, and analyze the composition and diversity of microbial communities sampled from different regions, and explore the relationship between soil microbial diversity and soil physicochemical properties. The results showed that a total of 33862 OTUs, belonging to 38 phylums, 88 orders, 214 orders, 514 families and 2268 genera, were obtained from the paddy rice rhizosphere soil samples collected from the four regions by sequencing. At the phylum level, the dominant phyla of paddy rice rhizosphere soil bacteria collected from the four regions were Proteobacteria, Bacteroidetes and Firmicutes. At the genus level, Limisphaera was the dominant taxon of paddy rice rhizosphere soil bacteria. As shown by the Alpha diversity index, the species diversity and richness of paddy rice inter-root soil bacteria collected from the four regions were generally as followed: 68th Regiment of the Corps (D)> Dairy Farm of Yili Prefecture (A)> Chabchal Town (B)> Sundzach Niuzhu Township (C); the Beta diversity index indicated that the paddy rice rhizosphere soil collected from the four regions differed accordingly in their bacterial community compositions, with greater differences existed between group A and other groups. The correlation analysis between soil bacteria and environmental factors concluded that the main influencing factors on the composition of microbial bacterial communities in paddy rice rhizosphere soils might be nitrogen, total potassium, and organic carbon. This study clarified the rhizosphere soil conditions and rhizosphere soil bacterial community characteristics of paddy rice distributed in the Ili River Valley, and provided theoretical support for the study of soil ecosystems in the Ili River Valley.
The research aims to study the status of molybdenum (Mo) in soils of China, optimize the application technology of molybdenum fertilizer, improving the absorption and utilization efficiency of Mo by crops, and promoting crop growth and yield. The content of total Mo and available Mo in soils of China was clarified through collecting data, the supply of soil Mo was evaluated, and the effects of different molybdenum fertilizer application rates and methods on crop growth and yield were studied. The range of total Mo content in soils of China was 0.1-6 mg/kg, with an average of 1.7 mg/kg, slightly lower than the world average; the content of available Mo in soil was affected by parent material of soil formation, soil pH value, etc., and the available Mo content was low in northern loess parent material soil and acidic soil in the south; the application of molybdenum fertilizer could significantly improve the yield and quality of crops such as soybeans, and the effects of seed treatment and foliar spraying were significant. The content of Mo in soils of China is insufficient, especially in northern loess parent material soil and acidic soil in the south, and molybdenum fertilizer should be applied to improve the availability of soil Mo; the rational application of molybdenum fertilizer is of great importance for improving crop yield and quality, especially in areas with low Mo content; the application methods of molybdenum fertilizer are diverse, and seed treatment and foliar spraying are effective application methods that can improve the absorption and utilization of Mo by crops.
In order to optimize wheat sowing date in the Jianghan Plain, enhance the adaptability to climate change, and promote wheat yield and quality, the temporal and spatial characteristics of meteorological suitability in winter wheat were compared based on the meteorological suitability evaluation model. Results showed that, climate change could increase the temperature suitability and precipitation suitability, but reduced that of sunlight. Delaying the sowing date could appropriately improve the meteorological suitability. Among them, November 11th was the best sowing date, next was November 21st and November 1st, by enhancing the temperature and precipitation suitability from the jointing to maturity stage. Compared with the traditional sowing date (October 21st), delaying sowing for about 20 days (November 11th) is beneficial for improving the meteorological suitability in the Jianghan Plain.
In order to provide reference for rational fertilization and green disease prevention and control in flue-cured tobacco, the effects of boron and silicon nutrient elements on the diseases prevention and control and the physiological mechanism were discussed. The field experiment was conducted to study the effects of different boron and silicon application levels on the incidence of potato virus Y (PVY) disease and defense enzyme activity of flue-cured tobacco named ‘Yunyan 100’. The results showed that the application of boron and silicon reduced the incidence and disease index of PVY in flue-cured tobacco. Compared with the treatment of spraying water (CK), the incidence and disease index of PVY under 9.0 kg/hm2 boron+ 6.0 kg/hm2 silicon treatment decreased by 32.5% and 22%, respectively. Meanwhile, reasonable application of boron and silicon fertilizer significantly improved the defense enzymes activities of tobacco leaves, and the phenylalanine degradation enzyme activity and proline content were significantly increased by 121.4%-426.5% and 30.0%-74.3%, respectively. Correlation analysis showed that the incidence of PVY was significantly negatively correlated with proline content, while phenylalanine degradation enzyme activity was significantly positively correlated with proline content. The combined application of 9.0 kg/hm2 boron+ 6.0 kg/hm2 silicon could reduce the occurrence of diseases and induce the increase of defense enzyme activity.
Sugarcane pokkah boeng disease is a fungal disease caused by multiple species of Fusarium. In order to clarify the pathogen species of sugarcane pokkah boeng disease in Yunnan, thirty-three samples of sugarcane pokkah boeng disease were collected from Kaiyuan and Menglian in Yunnan, and strains FS1 and FS2 were isolated and purified, and their DNA was extracted; the primers of transcription elongation factor (EF-1α), tubulin gene (TUB2), polymerase gene (RPB2) were used for PCR amplification of the isolated strains. The result was that a clear and bright band consistent with the target band was obtained, and the products were sequenced and analyzed by BLAST on the NCBI website, the EF-1α, TUB2 and RPB2 sequences of strains FS1 and FS2 were compared with EF-1α (accession number: MK609907.1), TUB2 (accession number: MT011039.1) and RPB2 (accession number: MW238849.1) of Fusarium sacchari with 100% similarity and coverage. Phylogenetic trees of strains FS1 and FS2 were constructed by maximum likelihood method with MEGA6.0 software, and the results showed that FS1 and FS2 clustered on the same branch with F. sacchari. Therefore, based on the morphological characteristics of strains FS1 and FS2 and the results of molecular biological identification, the pathogen of sugarcane pokkah boeng disease was identified as F. sacchari. F. sacchari spores were inoculated with ‘Yunzhe 08-1609’, and the symptoms of leaf regression and leaf yellowing appeared on the 7th day of inoculation, the infected leaves were isolated and sequenced again. The sequence similarity and coverage between EF-1α of the isolated strain and EF-1α of F. sacchari (accession number: MK609907.1) were 100%. F. sacchari was shown to be the causal agent of sugarcane pokkah boeng disease in Kaiyuan and Menglian.
The cultivation area of Astragalus membranaceus was expanding year by year. However, due to the continuous cropping obstacles, the problems of pests and diseases are becoming more and more serious year by year. In order to provide a basis for the identification and integrated prevention and control of diseases in the planting process of A. membranaceus, this paper reviews the occurrence patterns, pathogen species and prevention and control measures of the main diseases of A. membranaceus. The common diseases of A. membranaceus mainly include root rot, verticillium wilt, powdery mildew, downy mildew, damping-off and leaf spot, etc. Among these diseases, root rot and powdery mildew are particularly harmful to A. membranaceus. For these diseases, traditional prevention and control measures mainly rely on chemical agents, such as carbendazim, thiophanate-methyl and fludioxonil, etc. However, long-term dependence on chemical agents may not only have a negative impact on A. membranaceus itself, but also cause environmental pollution. The use of microorganisms such as Bacillus, Trichoderma and Streptomyces can effectively control the occurrence of diseases, while reducing the impact on the environment. In addition to the above methods, the cultivation of A. membranaceus varieties with strong resistance can fundamentally reduce the occurrence of diseases. Moreover, optimizing cultivation methods and strengthening field management, such as rational crop rotation, improving soil structure, controlling irrigation and fertilization, are also key measures to prevent diseases. In summary, the prevention and control of A. membranaceus diseases should adopt a comprehensive management strategy, including biological control, breeding of disease-resistant varieties, optimization of cultivation techniques and strengthening of field management, so as to achieve efficient and environmentally friendly disease control.
To clarify the impact of stalk-cutting harvest on the quality of upper tobacco leaves after curing, this study utilized ‘Yunyan 87’ as the test material. Various multivariate data analysis methods, including principal component analysis (PCA), partial least squares discriminant analysis (PLS-DA), variable importance in projection (VIP), and Pearson correlation analysis, were employed to investigate the differences in appearance quality, physical properties, chemical composition, and sensory quality between stem-leaf and leaf-by-leaf cured tobacco from six towns in Hubei Province. The results indicated that after excluding outlier indicators, the PLS-DA model showed R2X=0.578, R2Y=0.997, Q2PLS-DA=0.96, demonstrating the model’s effectiveness. A validation through 200 iterations of response sorting yielded R2intercept and Q2intercept values of 0.903 and -0.0125, respectively, indicating a good model fit. A total of 27 variables with significant differences were selected based on VIP values greater than 1.0, including reducing sugars, total sugars, sensory quality, and various amino acid contents. Among these, six variables—total sugars, reducing sugars, total sensory weight score, aroma quality, off-flavors, and irritation—exhibited positive effects, while the remaining 21 variables showed negative effects. In summary, the stalk-cutting and curing is beneficial for increasing the content of total sugars, reducing sugars, and certain sensory factors in the upper leaves, but it is detrimental to the increase of total nitrogen and amino acid contents.
In order to clarify the baking characteristics of the US-introduced tobacco variety ‘NC297’, the traits of color characterization, yellowing and browning, water loss, chlorophyll degradation, and polyphenol oxidase activity of different parts of the tobacco leaves in the dark-box test were investigated by using the intensive baking room and dark-box test method with ‘NC297’ as the material. The results showed that: (1) in the dark-box test, the yellowing degree of the middle and lower leaves was close to 100% at 96 h, while the upper leaves were not completely yellowed until more than 120 h, indicating that the baking ease of the middle and lower leaves of ‘NC297’ was moderate, but the baking ease of the upper leaves was poor. (2) During the baking process, the polyphenol oxidase activity of the upper fresh tobacco leaves of ‘NC297’ was 0.46 ∆OD398 nm/(g·min), significantly higher than that of the middle and lower leaves of ‘NC297’ which was 0.22 ∆OD398 nm/(g·min), indicating that the middle and lower leaves of ‘NC297’ were more resistant to baking, and the upper leaves were moderately resistant to baking. However, the browning degree of the lower leaves was close to 30% at 144 h, which indicated that the browning degree of the lower leaves among different parts of the tobacco was relatively poor. (3) In terms of chemical composition, with the increase of baking time, total sugar, reducing sugar and total amino acid content gradually increased, while total nitrogen, protein and starch content gradually decreased. To summarize, ‘NC297’ has medium baking ease in the middle and lower leaves, poor baking ease in the upper leaves, the order of baking resistance is middle leaves> upper leaves> lower leaves, and the chemical compositions of the flue-cured leaves are more coordinated, and the quality is significantly improved.
In order to determine the suitable altitude for planting high-quality flue-cured tobacco in Panzhihua, the chemical composition, appearance quality and sensory quality of tobacco leaves at different altitudes (1800-2400 m) were compared and analyzed. The results showed that the sensory quality of tobacco leaves at different altitude showed a trend of 1800 m≈ 2100 m> 2400 m. The aroma quantity, aroma temperament, impurity and aftertaste of tobacco leaves were better at 1800 m than that at 2400 m. The appearance quality of C3F and B2F tobacco leaves decreased with the increase of altitude. The appearance quality of B2F tobacco leaves at 1800 m and 2100 m was significantly better than that at 2400 m. When the altitude was more than 2100 m, the nicotine content in the upper leaves was higher and the potassium content was lower, and the chemical composition coordination of tobacco leaves became worse. In conclusion, the altitude of 1800-2100 m is the appropriate altitude for planting high-quality tobacco leaves in Panzhihua, and the tobacco leaves have better appearance quality, chemical composition coordination, and higher aroma quantity and aroma temperament.
To explore the quality differences of tomatoes with different fruit types, this study used gas chromatography-mass spectrometry (GC-MS) technology to detect and analyze the main flavor compounds of sugar, acid, and amino acids in cherry tomatoes, tasty tomatoes, and large tomatoes. The results indicated that fructose, glucose, and sucrose were the main soluble sugars in tomatoes. Among them, soluble sugar content in cherry tomatoes of ‘Busan 88’ and ‘Cherry Tomato of Tianshan Mountain’ were higher, while those in large tomatoes of ‘Liaoyuan Meili’ and ‘Provence’ were opposite. Overall, cherry tomatoes had the highest soluble sugar content, and large tomatoes had the lowest soluble sugar content. The detected organic acids were mainly citric acid, with the highest content in tasty tomatoes of ‘Fenbeier’ and ‘Yulinglong’, while it was lowest in large tomatoes of ‘Liaoyuan Meili’ and ‘Provence’. The total content of organic acid in tasty tomatoes was 1.39 and 1.88 times than that in cherry tomatoes and large tomatoes, respectively. A total of 8 amino acids were detected in 7 tasty tomato cultivars, 6 cherry tomato cultivars, and 3 large tomato cultivars. There was no significant difference in amino acid content between cherry tomatoes and tasty tomatoes, while both were significantly higher than large tomatoes. This study showed significant differences in accumulation levels of soluble sugar, organic acids and amino acid among different fruit types of tomatoes.
The aim of this study was to design a low-cost, efficient and non-destructive method for identifying and classifying common bean seeds based on machine vision (MV). In this study, image information of 2751 seeds of six varieties of common beans was collected, and based on image processing such as binarization, color extraction and morphological operations, nine features including color features, texture features and geometric features were extracted as the basis of classification, and K-nearest neighbor (KNN), random forest (RF), and support vector machine (SVM) classification models were established to classify the varieties of bean seeds. After comparing the confusion matrix, accuracy and F1 value of the three classification models, it was found that the SVM model outperformed the other two classification models, with a classification accuracy and F1 value of 97.7% and 0.977, respectively. The results of the study show that accurate identification and classification of common bean seeds can be achieved using MV.
