The effect of exogenous sugar solution and high concentration of CO2 on the contents of sugar and protein ofBetula platyphylla leaves

Abstract

The content of total sugar sucrose, fructose and protein in the leaves of 3-yr-oldBetula platyphylia was measured after the treatment by three exogenous sugar solutions (sucrose, fructose, glucose) and three high concentrations of CO2 (700, 1 400, 2 100 μL·L−1) for about a month in 1998. The results showed that spraying three exogenous sugar solutions increased markedly the content of sugar and protein of leaves under 700 μL·L−1 and 1 400 μ L·L−1 CO2. The effect of spraying exogenous sucrose solution was the best among the three exogenous sugars. The treatment of spraying exogenous sugar solution and 2 100 μL·L−1 CO2 constrained the accumulation of total sugar and protein of leaves. There was no different in protein content of leaves when spraying glucose and fructose solutions under 700 μL·L−1 and 1 400 μL·L−1 CO2. The treatment of 2 100 μL·L−1 CO2 concentration significantly increased the contents of total sugar, sucrose, fructose, and protein of leaves compared with that of the 700 μL·L−1 and 1 400 μL·L−1 CO2 except the plants spraying fructose solution. There was positive correlation between the content of sugar of leaves and CO2 concentration when spraying same exogenous sugar solution.