模拟酸雨对杉木种子萌发和幼苗生长的影响

将杉木种子和当年生幼苗置于不同pH值的模拟酸雨条件下观测和分析其生理和生长变化。结果表明，pH2．0和pH3．5的模拟酸雨严重抑制了种子的萌发和幼苗的成活，其它处理则没有明显的影响。在pH2．0的模拟酸雨条件下，杉木幼苗叶片表现明显的受害症状，叶绿素含量下降，细胞透性增加，叶汁液酸化，从而使幼苗生长严重受阻。pH3．5的处理对幼苗叶片的伤害也比较明显，导致叶汁液pH值下降，生长量呈现下降趋势。pH5．0的处理对幼苗生长产生一定的促进作用，而pH6．0的模拟酸雨对种子萌发和幼苗生长的影响不明显。

Effects of Simulated Acid Rain on Seed Germination and Seedling Growth of Cunninghamia lanceolata

Observation and analysis were made on changes in physiology and growth of seeds and seed- lings of Cunninghamia lanceolata which were subjected to a simulated acid rain adjusted to different pH levels. The results showed that pH2.0 and pH3.5 acid treatments were found to significantly inhibit seed germination and subsequently the survival rate of the seedlings. Under the exposure to pH2.0 treatment, seedling growth was severely retarded, due to the visible damage to foliage, decreased chlorophyll contents, elevated leaf cell permeability, and acidified leaf sap. The pH3.5 treatment also caused foliar damage and decline in pH of the leaf sap, leading to growth inhibition of the seedlings. Growth was stimulated by pH5.0 acid treatment, but no significant treatment effects were observed at pH6.0.