中文摘要：

采用LI－6400便携式光合测定系统测定了黑龙江省佳木斯市孟家岗林场不同立地条件、不同龄组长白落叶松的气体交换参数。结果表明，饱和光照强度下长白落叶松的气孔导度、蒸腾速率和水分利用效率受针叶朝向（阳生叶和阴生叶）、立地条件和林龄的影响而表现出不同。除幼龄林立地指数为12的阳生叶和阴生叶气孔导度、蒸腾速率和水分利用效率，幼龄林立地指数为18的阳生叶和阴生叶气孔导度和蒸腾速率，近熟林立地指数为17的阳生叶和阴生叶蒸腾速率存在显著差异外，其余所有林龄相同立地指数的阳生叶和阴生叶气孔导度、蒸腾速率和水分利用效率均无显著差异。近熟林的阳生叶和阴生叶气孔导度，中龄林和近熟林的阳生叶水分利用效率受立地条件的影响均不显著；幼龄林阳生叶和阴生叶的水分利用效率，近熟林阳生叶和阴生叶的蒸腾速率均随着立地指数的增加表现出显著升高的趋势；幼龄林和中龄林阳生叶和阴生叶的气孔导度和蒸腾速率，中龄林和近熟林的阴生叶水分利用效率均随着立地指数的增加表现出显著降低的趋势。饱和光照强度下阳生叶和阴生叶气孔导度和蒸腾速率受林龄的影响显著，而水分利用效率受林龄的影响不显著。

英文摘要：

The gas exchange parameters of young, middle-age and near-mature Larix olgensis , which were growing in different site conditions and age groups of Mengjiagang forest farm in Jiamusi city, were measured with a LI-6400 portable photosynthesis system. The result shows that the effect of conifer position in crown （ sun conifer and shade conifer）, site condition and forest age on stoma conductance （ Gs）, transpiration rate （ Tr） and water use efficiency （WUE） of larch in saturated light intensity are different. There are no significant difference of sun conifer and shade conifer in Gs,Tr and WUE of all the same site-index and forest-age larch plantations except G. ,Tr and WUE of young larch growing in 12 site index, G. and Tr of young larch growing in 18 site index, and Tr of near-mature larch growing in 17 site index. The effect of site condi- tions on Gs of near-mature larch, and sun conifer WUE of middle-age and near-mature larch are not significant; the WUE of young larch and Tr of near-mature larch significantly increases with the increasing of site index; G, and Tr of young and middle-age larch, and shade conifer WUE of middle-age and near-mature larch significantly decreases with the increasing of site index. The effect of forest age on Gs and Tr of larch are significant;the effect of forest age on WUE of larch is not significant.