涝渍胁迫对鸡爪槭幼苗光合生理特性的影响

通过设置对照（CK）、涝害（LH）和渍害（ZH）3种水分处理，研究鸡爪槭2年生实生苗的生理生态适应机制。结果表明:与CK比对，LH和ZH组鸡爪槭幼苗除胞间CO₂浓度升高，净光合速率（P_n）、气孔导度（G_s）均显著降低；P_n 、G_s在试验初期下降稳定，随着处理时间延长至第20天下降加速；LH和ZH组光合色素含量一直处于下降，受到胁迫显著；叶绿素a与叶绿素b的含量比值介于2.65~4.42之间，叶绿素与类胡萝卜素含量比值则在4.55~5.94之间。不同水分处理均显著影响鸡爪槭幼苗叶片气体交换以及光合色素，鸡爪槭幼苗表现出不耐水淹的生理生态特性。

Effects of Waterlogging Stress on the Photosynthetic Physiological Characteristics of Acer palmatum Seedings

Seedlings of 2-year-old potted Acer palmatum seedlings were used to examine the effects of water stress on the physiological and ecological adaptation mechanisms. Three treatment were established, normal (control), water stressed (ZH, in which soil was saturated by water), severe water stress (LH, in which water level was 5cm above soil surface). Compared with the cotrol, the seedling’s net photosynthetic rate (P_n) and stomatal conductance (G_s) in treatments LH and ZH were significantly low, while the intercellular carbon dioxide concentrations were high. The P_n and G_s in LH and ZH declined steadily at the early stage of the treatments, and declined rapidly from the day 20. The photosynthetic pigment contents of LH and ZH had been declining throughout the test period, indicating the synthesis of the pigments was seriously stressed. The ratio of chlorophyll a to b in three treatments ranged from 2.65 to 4.42, and the ratio of chlorophylls to carotenoids ranged from 4.55 to 5.94. The fact that different water treatments could effectively influence seedlings’ leaf gas exchange and contents of photosynthetic pigment indicated that the A. palmatum presented physiological and ecological features of non-tolerance to water stress.