长白山地区蒙古栎光合特性

Photosynthetic Characteristics of Quercus mongolica in Region of Changbai Mountain

基于单叶尺度上的光强-光合响应以及CO2-光合响应测定,对长白山地区蒙古栎成树和幼树的光合特性分别进行了研究.结果表明,蒙古栎成树的光补偿点Lcp为21μmol/(m2·s),光饱和点Lsp为1564μmol/(m2·s),表观量子效率α为0·045;幼树的Lcp、Lsp、α以及CO2补偿点、饱和点分别为29μmol/(m2·s)、1581μmol/(m2·s)、0·049、73μmol/mol、625μmol/mol.幼树和成树具有相似的光响应特征,但前者的光合同化能力要高于后者.蒙古栎具有典型的喜光性,但对高光的利用效率要低于弱光.

The photosynthetic characteristics of Quercus mongolica were studied based on the measurement of leaves photosynthesis under artificial controlled conditions of light intensities and CO2 concentration in the region of Changhai Mountain. For mature trees, the light compensation point Lop, light saturation point L,p and apparent quantum efficiency a were 21 μmol/（ m^2.s）, 1564μmol/（m^2 .s） and 0. 045, respectively. For young trees, the values of Lep, Lsp, α, and CO2 compensation point, CO2 saturation point were 29μmol/（m^2. s）, 1581μmol/（ m^2. s） ,0.049, 73μmol/mol,625μmol/mol, respectively. The photosynthesis assimilation of young trees was more active than that of mature trees. It suggested that the Quercus mongolica was intrinsically helophytic plant, but the use efficiency of light quantum was low in the strong light condition. The results also showed that the diurnal variations of net photosynthetic rote of young trees assume a typical midday depression pattem. Strong light intensity and high VPD were the key factors.