模拟酸雨对紫茎泽兰种子萌发和幼苗生长及化感作用的影响

Effects of simulated acid rain on seed germination,seedling growth and allelopathic potential of Eupatorium adenophorum

酸雨作为全球环境问题中的一个重要议题,但与生物入侵的关系常常被人们忽视.文中利用外来入侵植物紫茎泽兰(Eupatorium adenophorum)作为研究对象,研究模拟酸雨(p H分别为2.5、4.0和5.6,并且H2SO4与HNO3摩尔浓度比为5.17∶1的混合酸溶液)对其种子萌发和幼苗生长的影响.同时将酸雨污染与生物入侵通过化感作用联系起来,用模拟酸雨浸提紫茎泽兰叶片化感物质,考察其对受体植物旱稻(Oryza sativa L.)、黑麦草(Lolium perenne)、紫花苜蓿(Medicago sativa)和小麦(Triticum aestivum L.)种子萌发和幼苗生长的影响.结果表明:酸雨存在时,紫茎泽兰种子萌发和幼苗生长受到明显抑制,尤其在p H 2.5的模拟酸雨下,紫茎泽兰已完全不能发芽.对于紫茎泽兰化感作用来说,当以旱稻和小麦为受体植物时,模拟酸雨并未增强紫茎泽兰浸提液的抑制作用;但当以黑麦草和紫花苜蓿为受体植物时,模拟酸雨显著增强了紫茎泽兰浸提液的化感作用效果.

As one of the most important issues of global environmental problems,acid rain may have a close relationship with biological invasions. Here we used Eupatorium adenophorum,the most destructive alien plant species in China,to study the effects of simulated acid rain（ mixed acid solution made of H2SO4 and HNO3,5. 17 ∶ 1） on its germination and seedling growth. Since allelopathy serves as＂bridge＂in connection of acid rain pollution and biological invasion,we also used simulated acid rain to leach E. adenophorum leaves to study its impact on germination and seedling growth of four plant species,Oryza sativa L.,Lolium perenne,Medicago sativa,and Triticum aestivum L. The results showed that the germination and seedling growth of E. adenophorum were significantly inhibited by simulated acid rain. Especially when p H 2. 5 simulated acid rain applied,E. adenophorum could not germinate completely. By the analysis of E. adenophorum allelopathic effects on four receptor plants,simulated acid rain did not increase the inhibitory effects of E. adenophorum leachate on Oryza sativaand Triticum aestivum. However,simulated acid rain enhanced the toxicity of E. adenophorum leachate on Lolium perenn and Medicago sativa.