Effects of different potassium application rates on photosynthetic rate and potassium content of tobacco plants.

Under the condition of applying different quantities of high-efficient potassium,the daily changes in the photosynthetic rate of tobacco plants at bud stage,and the changes in the potassium content in various parts of tobacco leaves during the growth and development of tobacco were studied.The results showed that both the control(CK) and K2SO4 treatment had a nap phenomenon.The application of high-efficient potassium could better improve the photosynthetic performance of tobacco plants than K2SO4 treatment.Within 60 days after transplanting,the potassium content in tobacco leaf increased with the increase in the application rate of potassium fertilizer.After this,the potassium content in tobacco leaf deceased when the application rate of potassium fertilizer increased to a certain limit,and this phenomenon appeared firstly in K2SO4 treatment and in the middle or upper leaves.On the 30th day after transplanting,the potassium contents in the root and stem of tobacco plants increased with the increase in potassium application rate.While they first increased and then decreased in other testing periods.Throughout the whole growth period(except for the 60th day and 75th day after transplanting in CK),the potassium content in the stem was higher than that in the root in all treatments.