The Effect of Drought Stress on Photosynthetic Physiological Characteristics of the Different Tobacco Varieties

In order to understand the photosynthetic physiological characteristics differences of various flue-cured tobacco varieties under drought stress, a pot experiment was conducted to determine the effects of mild and severe drought stress on the photosynthetic physiological indices of five flue-cured tobacco varieties: Jiucaiping 2, Qianxi 1, Bina 1, Yunyan87, Yunyan 97 and the relationship with the drought resistance as well. The results showed that, in severe drought treatment, on average, the net photosynthetic rate of five tobacco varieties dropped 48.5%, intercellular CO₂ concentration increased 80.9%, transpiration rate decreased 33.6%, stomatal conductance decreased 72.7%. The photosynthetic rate of variety Qianxi 1 and Yunyan 97 decreased less than those of the others, which demonstrated relatively high drought tolerance.