CO_2增加对榆树·江孜沙棘光合特性的影响

Effect of Different CO_2 Concentrations on Photosynthetic Physiological Characteristics of Ulmus pumila and Hippophea rhamnoides

[目的]研究CO2增加对榆树、江孜沙棘光合特性的影响。[方法]利用Li-6400型便携式光合测定系统研究拉萨半干旱河谷地区主要造林树种榆树、江孜沙棘在不同CO2浓度下的光合特性。[结果]在弱光下榆树净光合速率较低,而强光下较高;随着CO2浓度增加,榆树的水分利用效率大幅增加。江孜沙棘对CO2浓度升高具有较好的适应性,使江孜沙棘同化CO2的能力和对光能利用效率提高,但当CO2浓度超过600μmol/mol时,其光合作用稍有下降。CO2浓度升高后提高了江孜沙棘对水分的利用效率。[结论]榆树和江孜沙棘具有喜光和抗旱性较强的特性,适宜在半干旱地区栽培。

[Objective] The aim was to study effect of different CO2 concentrations on photosynthetic physiological characteristics of Ulmus pumila and Hippophea rhamnoides [Method]The photosynthesis characteristics of Ulmus pumila and Hippophea rhamnoides were studied in semi-arid valleys areas fo Lasa,Tibet,with the by portable photosynthesis system Li-6400.[Result]The results showed that the net photosynthesis rate（Pn） of U.pumila was lower in low light quantum,but Pn was the higher in a great light.As the increasing of CO2 concentration,the water use efficiency（WUE） of U.pumila increased progressively.The light saturation point and apparent quantum yield of H.rhamnoides were increased as increasing of CO2 concentration.The absorbing CO2 ability and utilization of light energy of H.rhamnoides were strengthen.When CO2 concentration was above 600 μmol/mol,Pn value reduced a little but the WUE still increased.[Conclusion]U.pumila and H.rhamnoides was fond of light and drought-resistance,so it was adapt to enviroment in the semi-arid valleys areas.