模拟酸雨对外来入侵植物三叶鬼针草生长及化感作用的影响

Effects of simulated acid rain on seedling growth and allelopathic potential of invasive alien species Bidens pilosa L.

外来入侵植物三叶鬼针草(Bidens pilosa L.)对我国华南地区生态系统造成严重危害,同时华南地区也是强酸雨分布区域。采用不同pH值(2.5,4.0,5.6)的模拟酸雨对三叶鬼针草种子和幼苗进行处理,测定其对种子萌发和幼苗生长的影响;室外模拟酸雨喷淋三叶鬼针草,生物测定三叶鬼针草叶片水浸提液对受体植物的化感作用的变化。结果表明:pH为4.0和5.6的酸雨处理后提高了三叶鬼针草种子的萌发率;pH为4.0的酸雨促进幼苗生长,增加幼苗苗高和生物量;而pH为2.5的酸雨抑制三叶鬼针草种子萌发率和幼苗生长。同时,pH 4.0和2.5酸雨增强了三叶鬼针草叶片水浸提液对受体植物的化感作用。研究表明:三叶鬼针草具有较强的耐酸能力,酸雨胁迫可能通过促进外来入侵植物三叶鬼针草的生长和提高化感潜力而有利于其进一步入侵。

Bidens pilosa L.,an invasion exotic weed,has caused substantial damage to ecosystem in southern China,which is also an acid precipitation area.Effects of simulated acid rain（SAR） with different pH on the seed germination,seedling growth and allelopathic potential of B.pilosa were evaluated in laboratory.The results showed that the germination rate of B.pilosa was increased in SAR treatment at pH 5.6 and 4.0.SAR at pH 4.0 significantly stimulated the seedling growth of B.pilosa,while SAR at pH 2.5 inhibited the seedling growth.SAR at pH 4.0 and 2.5 enhanced the allelopathic potential of aqueous leaf leachates of B.pilosa on the tested plants.These results indicate that B.pilosa can adapt the acid precipitation in southern China,and acid rain might accelerate further invasion of B.pilosa through growth stimulation and enhanced allelopathic potential.