The Influence On The Physicochemical Properties And Content Of Main Endogenous Hormones Of Flue-cured Tobacco Under Temperature At Night

Flue cured tobacco is an important economic crop in China, the temperature is one of the important ecological factors affecting the quality of flue-cured tobacco. On the one hand, This study used tobacco cultivars of’Yunyan 87’,’K326’,’Zhongyan100’ and ’Hongda’ as materials to analyze the effect of nighttime temperature increase on the contents of GA3,IAA and CTK in flue-cured tobacco, by using man-made climate chambers to simulate warming. The results showed that:(1)According to the average contents of continuous treatments in 25 days, with the increase of nighttime temperature and extension of treatment time, there is a temperature turning point between nighttime temperature and the tobacco seedling crown endogenous hormone in four varieties of flue-cured tobacco, the temperature turning point of CTK is 11 ℃ or 15℃, while that of GA3 is 11℃. The maximum contents of hormone are largely concentrated in 5 to 20 days. (2)Through the responses of different flue-cured tobacco varieties, the higher nighttime temperature is conducive to the accumulation of CTK and IAA in flue-cured tobacco seeding crown, the content of CTK of’Yunyan 87’reaches the largest amount after 20 days in T11, observed value:51.23mol·L-1 and IAA of that reaches the largest amount after 5days in T11, observed value:29.27mol·L-1; the content of CTK of’Zhongyan 100’ reaches the largest amount after 10 days in T11, observed value: 51.03mol·L-1 and IAA of that reaches the largest amount after 5days in T11, observed value: 32.72mol·L-1; the content of CTK of’K326’reaches the largest amount after 10 days in T15, observed value:44.65mol·L-1 and IAA of that reaches the largest amount after 20 days in T19, observed value:35.47mol·L-1; the content of CTK of ’Hongda’ reaches the largest amount after 15 days in T19, observed value:50.61mol·L-1 and IAA of that reaches the largest amount after 20 days in T19, observed value:29.57mol·L-1.On the other hand, this paper taking Yunyan 100 as sample, in the high-altitude area of Baoshan, during their growth duration. The results showed:(1)Leaf width and simple leaf weight in all parts of tobacco significantly increased, while length and stem ratio of upper leaves greatly decreased and thickness of middle and lower leaves increased largely. (2)The difference of total sugar and reducing sugar in all processed tobacco decreased in different degrees and the content of nicotine and chlorine cut largely, yet the content of potassium significantly increased and the total nitrogen content grew in different degrees than the control groups. (3)Cu、Fe contents of upper leaves greatly decreased, while Zn、Mn significantly increased; Fe contents of middle leaves greatly decreased, while Zn、Mn significantly increased; Cu、Fe、Mn contents of lower leaves greatly decreased, while Fe significantly increased; (4)The lutein、beta carotene、chlorogenic acid and rutin contents of lower leaves greatly increased, while the middle leaves content of malonic acid and malic acid notably dropped and the content of palmitic acid and oleic acid remarkably increased.