西藏川滇高山栎净光合速率对环境因子的响应

使用便携式光合系统仪LI-6400测定西藏川滇高山栎净光合速率的日变化及其对环境因子的响应。结果表明:川滇高山栎的净光合速率在11:00点左右达到最大值，然后逐渐下降，到20:00左右净光合速率降到0以下，转入暗呼吸。从川滇高山栎的日进程可以看出，叶片出现明显的“午睡”现象。在温度（15.5±2）℃，大气CO₂浓度386.5 μmol/mol和相对湿度48%±5%的条件下，光补偿点为22 μmol/（m²·s）左右，光饱和点在1 029 μmol/（m²·s）左右。在大气CO₂浓度为381.5 μmol/mol，相对湿度为48%±5%，光强800 μmol/（m²·s）的情况下，15~30℃川滇高山栎的净光合速率都是比较高的。

Response of Quercus aquifoliodes Net Photosynthetic Rate to Environmental Factors in Tibet

The daily chang of net photosynthetic rate (NPR) and its response to environment factors such as quantum radiation,relative humidity and CO₂ concentration of Quercus aquifoliodes was monitored with a portable photosynthesis system.It is showed that the maximal NPR happened at 11:00,then the rate decreased and down below zero at about 20:00 in which Quercus aquifoliodes entered dark respiration.From the Quercus aquifoliodes date advancement,the leaf blade has obvious the phenomenon.Under the condition of air temperature (15.5±2)℃,relative humidity 48%±5%,and CO₂ concentration 386.5 μmol/mol,the light compensation point of Quercus aquifoliodes is about 22 μmol/(m²·s) and its light saturation point is about 1 029 μmol/(m²·s).Under the condition of relative humidity 48%±5%,and CO₂ concentration 381.5 μmol/mol and saturated luminous intensity 800 μmol/(m²·s),net photosynthetic rate of Quercus aquifoliodes is high at 15~30℃.