重金属Pb对烟草愈伤组织的生长和抗氧化系统的影响

The Influence of Pb Stress in Growth and Antioxidant System to the Callus of Tobacco

Pb污染是重金属污染中的一种重要形式.利用烟草叶片作为实验材料,以加入不同浓度Pb2+的MS培养基作为基本培养基诱导烟草叶片产生愈伤组织,观察经不同浓度Pb2+处理后烟草叶片产生愈伤组织的生长情况,并测定愈伤组织中活性氧水平和SOD、CAT等抗氧化酶的活性变化.结果表明:烟草叶片的出愈率随着Pb2+处理浓度的升高而下降,且愈伤组织出现的时间也随着Pb2+处理浓度的升高而延迟.愈伤组织中O-.2产生速率在培养第53天时达到最大值.在培养第49天SOD活性会显著下降,且SOD活性在稳定后随着Pb2+处理浓度的上升呈先上升后下降趋势.H2O2含量在培养第49天时含量达到最高,且随着Pb2+处理浓度的升高H2O2含量上升趋势越大.H2O2含量的上升会激活CAT的活性,使其活性在培养第53天即显著上升.除80 mg/L Pb2+处理下的CAT活性上升趋势受到部分抑制外,其他浓度Pb2+处理下的CAT活性上升趋势与H2O2上升趋势相同.

Pb pollution is one of most important form in heavy metals pollutants. This study applied tobacco as materials and MS medium adding Pb in different concentrations as medium to cultivate tobacco leaves until callus appeared. The growth was documented. Furthermore, the levels of ROS（reactive oxygen species） and activities of antioxidant enzymes of SOD and CAT were measured and analyzed. The results showed that：The production rate of callus decreased as the concentration of Pb in the medium increased, as well as the time delayed when callus appeared. Activities of SOD decreased apparently the 49th day. Furthermore, the activities of SOD firstly increased and then decreased as the concentration of Pb in medium ascended. While the production rate of O2 increased significantly the 53th day ,just following the decline of activities of SOD. The concentrations of H2O2 calne to a head the 49th day. Moreover, the concentrations of H2O2 increased more when treated with higher concentrations of Pb. The increment of H2O2 would trigger increasing activities of CAT. Activities of CAT increased significantly the 53th day, right after the increment of H2O2 concentrations. Except concentrations in 80 mg/L, the increasing extent of CAT activities in different Pb concentrations was consistent with the increment of H2O2.