Biological traits and leaf chemical composition in Daning Tobacco.

【Objective】The characteristics of morphological, physiological and leaf chemical composition of Daning Tobacco were studied to provide references for using high quality variety resources of Daning Tobacco. 【Method】Biological characteristics of Daning Tobacco were investigated by comparing the differences with sun-cured tobacco Daning, Zhangcun and Gonghui, while the chemical composition characteristics were analyzed by investigating the contents of soluble sugar, reducing sugar, nicotine, crude protein and ratio of reducing sugar to soluble sugar, nitrogen to nicotine, sugar to nicotine in sun-cured Daning Tobacco. 【Result】Daning Tobacco plants were relatively taller plants with narrow leaves.Average rate of leaf length to width in Daning Tobacco(2.23) was 1.51-fold and 1.75-fold of that in Zhangcun Tobacco and Gonghui Tobacco, respectively. The leaf transpiration ratio in Daning Tobacco plant(1.57-6.14 μmol/m2·s)was lower than that in Zhangcun tobacco(3.29-6.08 μmol m-2s-1) and Gonghui tobacco(1.96-5.90 μmol/m2·s), while the photosynthesis rate, the stomatal conductance and the intercellular CO2concentration in Daning Tobacco plants were similar to those in other tested sun-cured tobacco plants. Daning Tobacco leaves contained lower level of nicotine ranged from0.42% to 1.27%, while owned richer potassium content(2.24%-2.95%), contained greater amount of crude protein(3.45%-4.95%) and exhibited higher ratio of sugar to nicotine(15.28-65.76). 【Conclusion】It was concluded that Daning Tobacco plants were tall and thin with long and narrow leaves. Their characteristics included weaker transpiration, lower amount of nicotine, higher amount of K and protein,and higher sugar-nicotine rate.