干旱胁迫对蒙古柞表观资源利用率的影响

Effect of drought stress on apparent resource utilization efficiency of Quercus mongolica.

比较研究了模拟干旱及自然水分梯度条件下蒙古柞树种光合生理指标 ,模拟干旱处理试验土壤含水量分别控制在田间持水量的 85 %～ 10 0 % (CK)、6 5 %～ 85 % (MW )和 4 5 %～ 6 5 % (LW ) .结果表明 ,干旱胁迫对蒙古柞幼树净光合速率、气孔导度、蒸腾速率、水分利用率、表观CO2 利用率和表观光能利用率等生理指标均产生明显影响 .野外自然条件下水分梯度对蒙古柞大树气孔导度、水分利用率和净光合速率有显著影响 ,但对蒸腾速率、表观CO2 利用率和表观光能利用率的影响不显著 ,中等水分条件可明显提高蒙古柞大树叶片的气体交换和水分利用率 ,说明蒙古柞树种叶片气体交换和表观资源利用率对干旱胁迫的响应程度不同 .蒙古柞树种是干旱可变植物 ,长期水分胁迫可提高树种的耐旱能力 。

To study the effect of drought stress on the physiological characteristics and resource utilization effciency of Quercus mongolica ,a dominant species in the Korean pine broad leaved forest in Changbai Mountain,a comparative experiment was carried out under three soil moisture gradients as 85%～100%(high water,CK),65%～85%(Medium water,MW),and 45%～65%(low water,LW) of field water bolding capacity. The results showed that net photosynthetic rate,stomatal conduction,transpiration rate,water utilization efficiency,apparent CO\-2 utilization efficiency and apparent light utilization efficiency of the seedlings of Quercus mongolica were all significantly influenced by simulated drought stress. Stomatal conduction,water utilization efficiency and net photosynthetic rate of large tress of Quercus mongolica were affected by the soil drought stress,while transpiration rate,apparent CO\-2 utilization efficiency,and apparent light utilization efficiency were not influenced. Mode rate soil water condition could greatly increase gas exchange and water utilization efficiency. These results indicated that the responses of gas exchange and resource utilization efficiency to various water stresses were diffe rent. Quercus mongolica was a species with variable resistance to drought stress,and the resistance would be improved by drought stress,especially moderate water stress.