模拟酸雨对薇甘菊种子萌发和幼苗生长的影响

Effects of simulated acid rain on seed germination and seedling growth of Mikania micrantha H.B.K

薇甘菊是入侵性杂草,已在我国华南地区及云南部分地区造成严重危害。我国华南地区同时也是强酸雨分布区域。采用不同pH值的模拟酸雨对薇甘菊种子及幼苗进行处理,测定其对种子萌发和幼苗生长的影响。测定了不同pH值下薇甘菊幼苗叶绿素含量、丙二醛含量、脯氨酸含量、超氧阴离子产生速率、超氧化物歧化酶和过氧化物酶活性。结果表明,薇甘菊种子具有较强的耐酸能力,pH≥3.5时均能正常萌发,pH≤3.0时不能萌发。不同pH值模拟酸雨对薇甘菊幼苗叶绿素含量影响不显著。随着模拟酸雨pH值下降,超氧阴离子产生速率上升,丙二醛含量、脯氨酸含量、超氧化物歧化酶活性和过氧化物酶活性呈先上升后下降。pH3.5时,丙二醛含量、脯氨酸含量、过氧化物酶活性均达最大值;pH4.0时超氧化物歧化酶活性达最大值。结果表明薇甘菊对华南地区酸雨胁迫表现出适应。

Mikania micrantha H.B.K, a harmful exotic weed causing great harm in southern China and part of Yurman. Southern China is also a acid precipitation area. Effects of simulated acid rain with different pH values on the germination and seedling growth of Mikania micrantha H.B.K were studied. The concentrations of chlorophyll, malonaldehyde （MDA）, proline, O2--production rate, and activity of superoxide dismutase （SOD） and peroxidase （POD） were determined. The results showed the seed can germinate over pH3.5 while cannot germinate below pH3.0. Simulated acid rain has no significant effect on concentrations of chlorophyll. While pH values of simulated acid rain fell, O2--production rate rose and concentrations of malonaldehyde （MDA）, proline, and activity of superoxide dismutase （SOD） and peroxidase （POD） rose first and then fell. Concentrations of malonaldehyde （MDA）, proline, and activity of peroxidase （POD） reached the peak at pH3.5 while activity of superoxide dismutase （SOD） reached the peak at pH4.0. The result indicated that Mikania micrantha H.B.K can adapt the acid precipitation in Southern China.