Cr^(6+)和Pb^(2+)重金属胁迫对大蒜发芽的影响

Effects of Two Kinds of Heavy Metals Including Cr^(6+) and Pb^(2+) on Garlic Germination

[目的]研究Cr6+和Pb2+胁迫对大蒜发芽的影响。[方法]测定了在Cr6+和Pb2+2种重金属胁迫下大蒜发芽过程中的根长、酶(SOD和CAT)活性及可溶性蛋白质含量。[结果]大蒜萌发过程中,Cr6+和Pb2+重金属浓度超过20 mg/L时对芽苗根长有明显的抑制作用;SOD和CAT对低浓度的重金属毒性具有一定的缓冲能力,在低浓度Cr6+胁迫下SOD活性随着金属离子浓度的增加而增大,且当处理浓度为50 mg/L时达到最大,而CAT活性在Cr6+浓度低于20 mg/L时逐渐增大;SOD和CAT活性在高浓度Cr6+(大于50 mg/L)或在Pb2+胁迫下随重金属离子浓度的增加而持续降低;在重金属(Cr2+、Pb2+)溶液各个浓度作用下随着时间延长可溶性蛋白质含量均表现出下降趋势,且随着浓度的提升下降趋势明显。另外,大蒜对Cr6+毒性的耐受性远高于对Pb2+。[结论]为深入探讨重金属对植物的毒害机制提供了理论依据。

[Objective] This study aimed to revealing the effects of two kinds of heavy metals including Cr6＋ and Pb2＋ on garlic germination.[Method] Root length,enzyme（SOD and CAT） activity and soluble protein content during garlic germination was determined under the stress of two kinds of heavy metals including Cr6＋ and Pb2＋.[Result] During garlic germination,there was an obvious inhibition on buds and seedlings when the concentration of heavy metals including Cr6＋ and Pb2＋ was more than 20 mg/L,while SOD and CAT had certain buffering ability to the heavy metal toxicity with low concentration.With the stress of Cr6＋ in low concentration,SOD activity increased with the increase of metal ion concentration,and then reached maximum when the treatment concentration was 50 mg/L,while CAT activity gradually increased when Cr6＋ concentration was lower than 20 mg/L.With the high concentration of Cr6＋（more than 50 mg/L） or the Pb2＋ stress,SOD and CAT activity continued to decrease with the increase of concentration of heavy metal ions.With various concentrations of heavy metal（Cr6＋ and Pb2＋） solution,soluble protein content showed the decreasing trend with time prolong,and the decreasing trend was obvious with the increase of concentration.Moreover,the tolerance of garlic on Cr6＋ toxicity was much higher than that on Pb2＋.[Conclusion] Two kinds of heavy metals including Cr6＋ and Pb2＋ have impacts on four factors mentioned above during garlic germination,and this study provides a theoretical basis for further discussion of the toxic mechanism of heavy metals on plants.