中文摘要：

对自然条件下沙生植物差巴嘎蒿的光合作用日变化及光响应等进行了观测。结果显示,差巴嘎蒿净光合速率日变化曲线为双峰型,有明显的光合＂午休＂现象,根据Farquhar和Sharkey的判别方法,差巴嘎蒿净光合速率在8：00-14：00期间下降主要由气孔因素造成,14：00后净光合速率的降低则主要由非气孔因素造成的。水分利用效率日变化曲线为双峰型,显示了差巴嘎蒿对干旱环境的强适应性。采用不同光响应和气孔导度模型对差巴嘎蒿光响应曲线进行了拟合,结果表明,直角双曲线修正模型和气孔导度修正模型模拟结果与实际观测值具有较好的一致性。

英文摘要：

The diurnal dynamics and light response curve of photosynthetic rate（Pn） were measured in Artemisia halodendron.Under natural conditions the diurnal dynamics of A.halodendron Pn showed double peaks with a significant mid-day depression.The decrease in Pn between 8：00-14：00 was attributed to the stomatal limitation and after 14：00 the decrease was due to non-stomatal limitation.Diurnal dynamics of water use efficiency was similar to that of Pn,showing its strong adaptation to drought.Furthermore,different photosynthetic response models and stomatal models were used to simulate the response and we found that the simulated value of a modified rectangular hyperbola model and modified stomatal model had the best fit with observed values.