模拟秋季酸雨对三角枫叶片光合生理特性的影响

以三角枫幼苗为材料,采用盆栽方法,研究了pH 5.6、pH 4.0、pH 3.0和pH 2.0酸度模拟酸雨胁迫对三角枫叶片光合生理特性的影响,以探讨酸雨胁迫下三角枫的光合生理响应机制。结果显示:(1)随着酸雨浓度的增加和胁迫时间的延长,三角枫叶片相对叶绿素含量下降幅度逐步增大;叶片丙二醛含量呈逐渐上升的趋势,且各处理均显著高于对照;叶片质膜透性和脯氨酸含量均呈先升高后降低的趋势,且pH 2.0处理的叶片质膜透性在试验20d时迅速增大,升高幅度最大(146.3%)。(2)叶片净光合速率、蒸腾速率、水分利用效率、表观光能利用效率以及表观CO2利用效率在胁迫下也均呈显著下降趋势,且以pH 3.0和pH 2.0处理降幅最大。研究表明,pH 4.0的模拟酸雨对三角枫叶片的光合生理指标无显著影响,而pH≤3.0的强酸雨胁迫使三角枫叶片叶绿素含量显著下降、膜保护系统受损、光合作用效率显著下降;三角枫能适应弱酸雨(pH≥4.0)环境,可作为酸雨地区的园林绿化树种。

Effects of Stimulated Acid Rain in Autumn on Leaf Photosynthetic Characteristics in the Leaf of Acer buergerianum Miq.

A pot experiment was conducted to explore the effects of stimulated acid rain treatments with different pH values (pH 5.6, pH 4.0, pH 3.0 and pH 2.0) in autumn on leaf photosynthetic physiological characteristics in the leaf of Acer buergerianum Miq. The results showed that: (1) the relative contents of chlorophyll in the leaf decreased with pH value of stimulated acid rain decreased, while content of MDA in the leaf increased. Membrane permeability and proline content firstly increased and then decreased during stimulated acid rain treatment. On the 20th day of the treatment, membrane permeability of plants growing under pH 2.0 reached the highest level of 146.3%. (2) The net photosynthetic rate, transpiration rate, water use efficiency as well as apparent light utilization efficiency and apparent CO₂ utilization efficiency significantly declined under stimulated acid rain treatments, especially under stimulated acid rain of pH 3.0 and 2.0. Comprehensive analysis showed that, stimulated acid rain treatment of pH 4.0 did not significantly affect leaf photosynthetic physiological characteristics, but stimulated acid rain at pH 3.0 and below make chlorophyll contents decreased, damage the membrane system and result in a significant decrease of photosynthetic rate. Also A. buergerianum Miq. is able to adapt to weak acid rain environment, that could be used as afforestation tree species in acid rain area.