红松光合特性对CO2浓度升高的响应

选取红松(Pinus koraiensis)为研究对象,利用Li-6400-01液化CO2钢瓶提供不同的CO2浓度(400、600、800 μmol·nol-1)测定红松光合特性,同时对净光合速率与相关环境因子的关系进行了分析.在3种CO2浓度处理下:净光合速率表现出单峰曲线的日变化格局,随CO2浓度增大,净光合速率增大且差异显著,没有明显的"午休"现象;气孔导度呈缓慢下降趋势,并随CO2浓度增大而减小;蒸腾速率基本呈减小趋势,且差异不显著;水分利用效率日变化格局有所不同,且随CO2浓度增加而增大.在不同CO2浓度处理下,对于净光合速率的主要影响因子有所变化,在对照试验中,蒸腾速率是主要因子;在其他(600、800 μmol·mo1-1)两个处理中,主要影响因子为气孔导度.

Photosynthetic Characteristics Responses of Pinus koraiensis to Elevated Carbon Dioxide Concentration

The photosynthetic characteristics of Pinus koraiensis in the field were determined with Li-6400 portable system by using Li-6400-01 carbon dioxide cartridge to provide different carbon dioxide concentrations, and the relationships between net photosynthesis rates and relative environmental factors were also discussed. The results show that under three treatments the net photosynthesis rate shows a daily pattern of single peak curve and the rate increases with carbon dioxide concentration, but it does not achieve significant level under different treatments, and there is no obvious decline at noon. The stomatal conductance slowly decreases with carbon concentration increasing. The transpiration rate decreases, but it does not reach remarkable level. The daily patterns of water use efficiency are different and water use efficiency enhances with carbon dioxide concentration increasing. The relative factors affecting net photosynthesis rate are various under different treatment, and the transpiration rate is the main factor in the control, while the stomatal conductance is the main factor in the other two treatments.