【摘要】 在盆栽条件下,研究了灌浆期燕麦在水分胁迫条件下光合有效辐射对叶片净光合速率、胞间CO2浓度及气孔导度的影响。结果表明,净光合速率对光合有效辐射的响应均呈直角双曲线变化,水分胁迫不仅使净光合速率减小,而且光补偿点、光饱和点及呼吸速率也明显降低;水分胁迫还使叶片胞间CO2浓度、气孔导度减小,且随光合有效辐射增强减小幅度增大;分析认为,气孔导度和光合速率直接影响胞间CO2浓度变化,但在水分胁迫条件下前者则是影响胞间CO2浓度变化的主要因素,也就是水分胁迫致使净光合速率下降更主要是由于气孔因素作用的结果。更多还原

【Abstract】 To determine how the photosynthetic characteristics of the leaf of annual C₃ plants respond to photosynthetic radiation,we used LI-6400 Portable Photosynthesis System to examine net photosynthesis rate（P_n）、intercellular CO₂ concentration（C_i） and stomatal conductance（Gs） of oats under different water stress in the pot experiment.Results show that net photosynthesis rate（P_n） increased with enhanced photosynthetic radiation intensity.At last,this physiological parameter tends to dynamic balance.And the increase of P_n under water stress is higher than that of controlled treatments.When the supply of CO₂ reaches the demand of it,the Gs tends to stabilization and increased with enhanced photosynthetic radiation intensity.Under water stress Gs is lower than that of checked ones and varies little with photosynthetic radiation intensity.For controlled treatments C_i reduced with enhanced photosynthetic radiation intensity and stabilization when photosynthetic radiation reaches certain level.While under water stress the stomatal closed,C_i dropped with photosynthetic radiation intensity and finally keeps lower level.The light compensation point（LCP） 、the light saturation point（LSP） and respiration rate（R_d） is clear lower than that of controlled treatments under water stress.更多还原