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Fu Y.,Henan Agricultural University | Liu Q.,Henan Agricultural University | Liu Q.,Jiangxi Provincial Tobacco Company | He X.,Yunnan Baoshan Oriental Tobacco Co. | And 2 more authors.
Acta Tabacaria Sinica | Year: 2013

Pot experiments of oriental tobacco plants were carried out to investigate effect of soil moisture on photosynthetic characteristics by using portable Li-6400 photosynthesis system during vigorous growing stage. Correlation analysis was conducted between environment factors and tobacco leaf characteristics, such as net photosynthesis rate and transpiration rate under different soil moisture levels. Results showed that (1) daily dynamics of Pn in oriental tobacco leaves under different soil moisture levels were all in the form of double peaks curves. Increase of soil moisture stress resulted in decline of peak value of Pn and midday depression intensified. (2) daily dynamics curves of Pn, Tr, Ci and Gs of oriental tobacco leaves showed significant differences under different soil moisture levels. (3) midday depression in oriental tobacco leaves may be controlled by both stomatal and non-stomatal factors. When soil moisture decline, non-stomatal is the main control factor. Correlation analysis indicated that Gs was key to Pn under three different treatments while air temperature under 65%-75% soil moisture and photosynthetic active radiation under 50%-60% and 35%-45% soil moisture levels were important to Tr. Maintaining relative soil moisture within 50%-60% may contribute to high levels of Pn and WUE. Source

Zhou G.,Yunnan Agricultural University | Yin X.,The University of Tennessee | Li Y.,Yunnan Agricultural University | Yang H.,Yunnan Agricultural University | And 6 more authors.
Agronomy Journal | Year: 2014

Relay cropping timing has been frequently reported to influence flue-cured tobacco (Nicotiana tabacum L.) production. However, the optimal planting time for a relay corn (Zea mays L.) crop on flue-cured tobacco fields is unknown in terms of tobacco health, yield, quality, and economic value. A field experiment was conducted with 10, 17, 24, and 31 d after flue-cured tobacco apex excision as the relay cropping timings of corn, and tobacco monoculture as the control at Chuxiong, Yunnan, China in 2010 and 2011. The five treatments were repeated three times in a randomized complete block design. The occurrence of brown spot (Alternaria alternata), plant biomass, plant N and K nutrition, yield, chemical composition, smoking quality, and economic value of flue-cured tobacco were affected by year. Relay cropping 17 d after tobacco apex excision resulted in better chemical composition and smoking quality. The incidence and severity index of brown spot, plant biomass, plant N and K nutrition, yield, chemical composition, smoking quality, and economic value of tobacco were not significantly affected by the relay cropping timing of corn, indicating that relay cropping of corn at a later growth stage of flue-cured tobacco has no negative effect on tobacco production while the relay corn crop may bring additional income to tobacco growers. In conclusion, if the production of relay corn is profitable, relay cropping of corn after flue-cured tobacco apex excision could become a recommended cropping system in Yunnan and other regions with similar environmental conditions. © 2014 by the American Society of Agronomy, 5585 Guilford Road, Madison, WI 53711. All rights reserved. Source

Fu Y.,Henan Agricultural University | Li G.,Henan Agricultural University | Li G.,Shanghai RDR Scientific Research and Development Institute | Song Y.,Yunnan Baoshan Oriental Tobacco Co. | And 4 more authors.
Acta Tabacaria Sinica | Year: 2014

Pot experiments were conducted with oriental tobacco to investigate effects of soil moisture on chemical composition, flavor components and sensory quality. Results showed that content of total soluble sugar, reducing sugar and volatile alkali in leaves decreased with declined levels of soil moisture. Content of total nitrogen and nicotine in leaves was the highest when the level of soil moisture was at 55%±5%, followed by t40%±5% and 70%±5%. With the level of soil moisture declining, the content of all flavor components in cutters, except neophytadiene and acetyl pyrrole, increased, so was the content of organic acids, phenylalanine degradation products and carotenoid degradation products in upper leaves. However, the content of labdannums and cembranoids in upper leaves decreased with the level of soil moisture declining. Three indicators of organic acids and the content of esters in upper leaves were in the highest degree when soil moisture was at 50% ± 5%. With the level of soil moisture declining, the quality of aroma improved with the volume and richness of aroma increasing and biting and undesirable taste decreasing, thus resulting in significant improvement of sensory quality. Sensory quality of upper leaf is best ensured at 50%~60% soil moisture level. ©, 2014, State Tobacco Monopoly Bureau and China Tobacco Society. All right reserved. Source

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