【摘要】 采用Li-6400便携式光合作用测定系统于2006年6～9月测定北京山区主要乔木树种的光合特性,包括刺槐、臭椿、槲树、栓皮栎、侧柏和油松。结果表明,自然状态下,栓皮栎、臭椿和刺槐的光合曲线呈双峰型,发生明显的"午休"现象。强光、高温和低湿是引起"午休"的主要环境因子。3个树种的气孔导度与净光合速率的变化趋势相似,也呈双峰型,但叶片胞间CO2浓度因树种不同而呈现不同的变化趋势。槲树、侧柏和油松的光合曲线呈单峰型。更多还原

【Abstract】 By using Li-6400 portable photosynthesis system,the diurnal changes of the photosynthetic rate of main arbor species were measured in mountainous area of Beijing City in June to September 2006,including Robinina pseudoscacia,Ailanthus altissima,Q.Dentata,Quercus variabilis,Platycladus orientalis,Pinus tabulaeformis.The results showed that net photosynthetic rate in the leaves of Quercus variabilis,Robinia pseudoacacia,Ailanthus altissima appeared in curvilinear changes with double peaks.And apparent strong light intensity,high temperature and low air humidity were the key influencing factors.The stomatal conductance was positively related to net photosynthetic rate closely,and they kept the same change trend.But the intercellular CO2 concentrations of these three species had different change trends.The results also showed that net photosynthetic rate in the leaves of Q.dentate,Pinus tabulaeformis,Platycladus orientalis appeared in curvilinear changes with one peaks.更多还原