Effects of Different Maturities on the Physiological Indexes of Tobacco Upper Leaves During Flue-curing Process

Purpose To explore the physiological and biochemical characteristics of the upper tobacco leaves during curing.

Method The effects of different maturities on the physiological indexes of the upper leaves during curing were studied by using K326 variety as the experimental material in the temperature and humidity self-controlled intensive curing barn.

Result (1) The main water loss period of tobacco leaves occurred between 42-54 ℃ during curing, and was advanced with the increase of maturity. (2) The degradation process of chlorophyll mainly occurred between the prebaking and the end of 42 ℃, and the mature and over mature tobacco leaves before the end of 36 ℃. (3) The content of MDA and polyphenol in tobacco leaves increased gradually with the increase of curing temperature, and the higher the maturity, the higher the content. (4) The activity of PPO increased at first and then decreased, and maximum at the end of 36 ℃, and the results showed that the over mature tobacco leaf was larger than the mature tobacco and under mature tobacco leaf. (5) The activity of POD increased first and then decreased, the activity of 38 ℃ was the greatest, and the POD activity of mature tobacco leaves was the greatest at this time. (6) The activity of SOD in over mature tobacco leaves decreased at first and then increased, while that in well-matured and under mature leaves decreased at first and then increased and then decreased, and then increased. (7) Correlation analysis showed that MDA content was positively correlated with polyphenol content, SOD was negatively correlated with POD activity, SOD activity was positively correlated with MDA and polyphenol content, and polyphenol content was negatively correlated with PPO activity in immature tobacco leaves.

Conclusion Comprehensive analysis shows that maturity has an important impact on the curing characteristics of tobacco leaves, and the physiological and biochemical indexes of the upper part of mature and over mature tobacco leaves show better curing characteristics.