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Chilling is a major abiotic factor limiting the growth, development, and productivity of plants. β-aminobutyric acid (BABA), a new environmentally friendly agent, is widely used to induce plant resistance to biotic and abiotic stress. Calcium, as a signaling substance, participates in various physiological activities in cells and plays a positive role in plant defense against cold conditions. In this study, we used tobacco as a model plant to determine whether BABA could alleviate chilling stress and further to explore the relationship between BABA and Ca2+. The results showed that 0.2 mM BABA significantly reduced the damage to tobacco seedlings from chilling stress, as evidenced by an increase in photosynthetic pigments, the maintenance of cell structure, and upregulated expression of NtLDC1 , NtERD10B , and NtERD10D. Furthermore, 0.2 mM BABA combined with 10 mM Ca2+ increased the fresh and dry weights of both roots and shoots markedly. Compared to that with single BABA treatment, adding Ca2+ reduced cold injury to the plant cell membrane, decreased ROS production, and increased antioxidant enzyme activities and antioxidant contents. The combination of BABA and Ca2+ also improved abscisic acid and auxin contents in tobacco seedlings under chilling stress, whereas ethylene glycol-bis (β-aminoethylether)- N,N,N ′, N ′-tetraacetic acid (EGTA) reversed the effects of BABA. These findings suggested that BABA enhances the cold tolerance of tobacco and is closely related to the state of Ca2+ signaling. [ABSTRACT FROM AUTHOR]

In order to manifest lower energy consumption and less labor employment, and provide the theoretical basis for constructing environmentally friendly modern tobacco agriculture, this paper analyzed gas composition of the chimney from a bulk-curing barn and the dispersion of sulfur dioxide (SO2) around the workshop cluster using ecom-J2KN flue gas analyzer and air sampler. During curing, the concentrations of carbon dioxide (CO2) and SO2 in the chimney were both highest at 38 176C, while the concentration of nitrogen oxides (NOx ) was highest at 42 176C. The emission concentration of SO2 from the chimney was 1327. 60-2218. 40 mg· m-3. Average SO2 emission would decrease by 49. 7% through adding 4. 0% of a sulfur-fixed agent. The highest concentrations of SO2 in the surface soil appeared at the yellowing stage. SO2 concentration in horizontal direction localized at 43-80 m exceeded 0. 5 mg· m-3. The highest concentration of SO2 (0. 57 mg· m-3 ) was observed at 50 m. At 50 m in the downstream wind direction of the workshop cluster, SO2 concentration in vertical direction localized at 0. 9-1. 8 m exceeded 0. 5 mg· m-3, and the highest concentration of SO2 in vertical direction was 0. 65 mg· m-3 at 1. 6 m. During curing, the average concentration of SO2 was decreased by 0. 43 mg· m-3 by using the sulfur-fixed agent. The polluted boundary was localized at 120 m in the downstream wind direction of the workshop cluster. [ABSTRACT FROM AUTHOR]

This paper studied the distribution characteristics of phosphorus contents of 107 flue-cured tobacco leaf samples from domestic main tobacco areas and Zimbabwe, and analyzed the relationships between phosphorus contents and routine chemical components. The results indicated that: CD the phosphorus content of domestic main tobacco areas ranged from 0.25% to 0.66% with the mean of (0.43 ±0.08) %, the phosphorus content of Zimbabwe ranged from 0.45% to 0.67% with the mean of (0.53 ± 0.05) %; (2) the order of the phosphorus contents in flue-cured tobacco leaves among different areas was Zimbabwe (0.53%) > Southeast tobacco area (0.49%) > the upper and middle Yangtze River tobacco area (0.45%) > Southwest tobacco area (0.42%) > the Yellow and Huai River tobacco area (0.41%) > North tobacco area (0.39%), and the differences among these areas reached extremely significant level; (3) the phosphorus contents increased with the rise of stalk position, and there was no significant difference among different positions; (4) the phosphorus content in flue-cured tobacco leaf had significant or extremely significant positive correlation with nicotine, potassium and chlorine contents, and had extremely negative correlation with total sugar, reducing sugar content and nitrogen/nicotine, sugar/nicotine, but had no significant correlation with total nitrogen and potassium/chlorine; (5) the clustering results based on the phosphorus contents and harmonic character evaluation of the chemical components at different phosphorus content levels showed that the flue-cured tobacco leaves with medium and high phosphorus content clusters had proper chemical components, better harmony among indexes and high available value. [ABSTRACT FROM AUTHOR]

Chilling is a major abiotic factor limiting the growth, development, and productivity of plants. β-aminobutyric acid (BABA), a new environmentally friendly agent, is widely used to induce plant resistance to biotic and abiotic stress. Calcium, as a signaling substance, participates in various physiological activities in cells and plays a positive role in plant defense against cold conditions. In this study, we used tobacco as a model plant to determine whether BABA could alleviate chilling stress and further to explore the relationship between BABA and Ca 2+ . The results showed that 0.2 mM BABA significantly reduced the damage to tobacco seedlings from chilling stress, as evidenced by an increase in photosynthetic pigments, the maintenance of cell structure, and upregulated expression of NtLDC1 , NtERD10B , and NtERD10D . Furthermore, 0.2 mM BABA combined with 10 mM Ca 2+ increased the fresh and dry weights of both roots and shoots markedly. Compared to that with single BABA treatment, adding Ca 2+ reduced cold injury to the plant cell membrane, decreased ROS production, and increased antioxidant enzyme activities and antioxidant contents. The combination of BABA and Ca 2+ also improved abscisic acid and auxin contents in tobacco seedlings under chilling stress, whereas ethylene glycol-bis (β-aminoethylether)- N,N,N ', N '-tetraacetic acid (EGTA) reversed the effects of BABA. These findings suggested that BABA enhances the cold tolerance of tobacco and is closely related to the state of Ca 2+ signaling., (Copyright © 2020 Ma, Xu, Han, Huang, Dang, Jia and Xu.)

In order to manifest lower energy consumption and less labor employment, and provide the theoretical basis for constructing environmentally friendly modem tobacco agriculture, this paper analyzed gas composition of the chimney from a bulk-curing barn and the dispersion of sulfur dioxide (SO2) around the workshop cluster using ecom-J2KN flue gas analyzer and air sampler. During curing, the concentrations of carbon dioxide (CO2) and SO2 in the chimney were both highest at 38 degrees C, while the concentration of nitrogen oxides (NOx) was highest at 42 degrees C. The emission concentration of SO2 from the chimney was 1327.60-2218.40 mg x m(-3). Average SO2 emission would decrease by 49.7% through adding 4.0% of a sulfur-fixed agent. The highest concentrations of SO2 in the surface soil appeared at the yellowing stage. SO2 concentration in horizontal direction localized at 43-80 m exceeded 0.5 mg x m(-3). The highest concentration of SO2 (0.57 mg x m(-3)) was observed at 50 m. At 50 m in the downstream wind direction of the workshop cluster, SO2 concentration in vertical direction localized at 0.9-1.8 m exceeded 0.5 mg x m(-3), and the highest concentration of SO2 in vertical direction was 0.65 mg x m(-3) at 1.6 m. During curing, the average concentration of SO2 was decreased by 0.43 mg x m(-3) by using the sulfur-fixed agent. The polluted boundary was localized at 120 m in the downstream wind direction of the workshop cluster.