模拟酸雨对小麦种子萌发和幼苗生长的影响

以中性溶液（pH=7.0）为对照，研究了pH值为1.0，2.0，3.0，4.0，5.0和6.0模拟酸雨对小麦种子萌发和幼苗生长的影响。结果表明，小麦种子萌发和幼苗生长各指标随着pH值的降低而降低，弱酸（pH5.0～6.0）条件下小麦种子能够正常萌发和生长，种子萌发和幼苗生长各指标与对照没有显著差异（P > 0.05）；在pH低于5.0时，小麦种子萌发和幼苗生长严重受阻，种子萌发和幼苗生长各指标均显著低于对照（P < 0.05）；pH为1.0时，小麦种子则完全失去活性；不同pH值模拟酸雨胁迫对小麦幼苗生理指标影响较大，叶绿素含量、类胡萝卜素含量、保护酶（SOD，POD，CAT）和非保护酶（PPO，PAL）活性随酸性的增强呈降低趋势，而相对电导率和丙二醛（MDA）含量呈上升趋势。综合分析认为，小麦幼苗生长比种子萌发对模拟酸雨的响应更为敏感。

Effects of Simulated Acid Rain on Seed Germination and Seedling Growth of Wheat

The effects of acid rain on seed germination and seedling growth of wheat which were treated with simulated acid rain at pH 1.0, 2.0, 3.0, 4.0, 5.0, 6.0 and 7.0 were studied. The results showed that the indexes of seed germination and seedling growth of wheat reduced with the decrease of the pH value and were inhibited by the lower pH. The indexes of seed germination and seedling growth of wheat were not significant compared with CK with the pH value from 5.0 to 6.0 (P > 0.05) and showed resistance to acid. When the pH value was less than 5.0, the seed germination and seedling growth of wheat were sharply inhibited and the indexes were significantly lower than CK (P < 0.05), while the wheat didn’t shoot up at pH 1.0 at all. The results also showed that simulated acid rain with different pH values had a larger effect on the seedling physiological indexes of wheat, the content of chlorophyll, carotenoid, protective enzyme (SOD, POD, CAT) and the protective enzyme (PPO, PAL) activity showed a decreasing trend with the increase of acid, but the relative conductivity and malondialdehyde (MDA) showed an increasing trend. Based on above results, we can conclude that the effect of simulated acid rain on wheat seedling growth was more sensitive than seed germination.