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以牛蒡为试材,研究浓度为0、50、150、300、600、800、1 000mg/L的铅(Pb)溶液对牛蒡种子萌发和幼苗生长的影响。结果表明:Pb溶液浓度为150mg/L时发芽率最高,50、150mg/L低浓度Pb溶液对牛蒡种子的萌发具有促进效应,当Pb溶液浓度大于150mg/L时则表现出递增抑制效应;不同浓度Pb胁迫下,牛蒡种子的发芽势、发芽指数和活力指数以及幼苗鲜重均表现出先升高后降低的趋势,且除幼苗鲜重外均在Pb2+浓度150mg/L时出现峰值;幼苗根长和芽长在Pb2+不同浓度胁迫下同样呈现出先增加后减小的趋势,其中幼苗根长和芽长分别在Pb2+浓度为50、150mg/L时出现峰值;幼苗叶片丙二醛和叶绿素含量随Pb2+浓度增加表现出持续升高趋势;幼苗叶片中超氧化物歧化酶(SOD)活性、过氧化物酶(POD)活性均表现出随Pb2+浓度增加先升高后降低的趋势,但二者活性在较高浓度Pb胁迫(>600mg/L)时仍能保持较高水平。试验结果表明,低浓度Pb处理对牛蒡种子萌发和幼苗生长具有一定促进效应,高浓度Pb则对其产生抑制作用,但高浓度Pb胁迫下牛蒡种子仍具有较高的萌发率,幼苗也可以正常生长,SOD、POD保持较高活性。
With burdock as test material, the effects of lead (Pb) solution with 0, 50, 150, 300, 600, 800 and 1000 mg / L on the seed germination and seedling growth of burdock were studied. The results showed that when the concentration of Pb solution was 150mg / L, the germination rate was the highest, while the low concentration of Pb solution of 50,150mg / L could promote the germination of burdock seed. When the Pb concentration was more than 150mg / L, the germination rate was increased. Under the Pb stress, the germination potential, germination index and vigor index of burdock seed and the fresh weight of seedling showed the trend of first increasing and then decreasing. Except fresh weight of seedling, the peak appeared at the concentration of Pb2 + 150mg / L; And bud length also increased firstly and then decreased with different concentrations of Pb2 +. The root length and shoot length of the seedlings peaked at the concentrations of 50 and 150 mg / L Pb2 +, respectively. The contents of MDA and chlorophyll in the seedling leaves changed with Pb2 + (P <0.05). The activity of superoxide dismutase (SOD) and the activity of peroxidase (POD) in seedling leaves all showed the trend of increasing firstly and then decreasing with the increasing of Pb2 + concentration. However, High concentrations of Pb stress (> 600mg / L) can still maintain a high level. The results showed that low concentration of Pb could promote seed germination and seedling growth of burdock, while high concentration of Pb could inhibit it. However, burdock seed still had higher germination rate under high concentration Pb stress and seedling could also be normal Growth, SOD, POD to maintain high activity.