摘要：采用水培法研究了汞铬离子单一胁迫对绿豆种子萌发及幼苗生长的影响。实验对每种离子各设计7个处理水平，均为15mg/L、30mg/L、45mg/L、60ｍg/L、90mg/L、120mg/L和150mg/L，且均以蒸馏水为对照。实验结果表明，同种浓度下，汞离子对绿豆的毒害作用要大于铬离子的毒害作用，对绿豆各方面的生理指标危害较大；同一离子不同浓度时，一般遵循，低浓度时对绿豆的生长起促进作用，中高浓度时抑制绿豆的生长，高浓度是直接将幼苗杀死。实验中发现，汞离子在浓度大于60mg/L时，对绿豆的伤害很大，基本上幼苗均呈现枯萎状。在汞离子胁迫液浓度达到150mg/L时，7天的胁迫下，绿豆幼苗均死亡，而铬离子在同种浓度下，长势相对较好。由此也可以看出，汞离子对绿豆幼苗的毒性要大于铬离子。在形态指标、生化指表和抗逆性指标的测定中发现，汞离子单一胁迫液在浓度低于45mg/L时对绿豆种子萌发及幼苗的各项指标均有一定的促进作用，且在浓度达到30mg/L时，促进达到峰值。铬离子单一胁迫液在浓度低于60mg/L时对绿豆种子的萌发及幼苗的各项指标有一定的促进作用，且浓度在45mg/L时达到峰值。但实验中发现汞离子对绿豆幼苗SOD活性的影响时，总体趋势是先降后增再降，在浓度为15mg/L时为降低，造成此结果的可能原因是汞离子对绿豆幼苗的毒害作用要强于其它离子，在胁迫初期汞离子就对绿豆幼苗产生影响，经过7天的胁迫后，造成绿豆幼苗对其有一定的抗性，故与其它研究幼苗SOD活性变化的实验结果不尽相同。

关键词：汞离子    铬离子    胁迫    绿豆  

Abstract : In this experiment, we did a research on individually effects of Hg2+ and Cr3+’s single stress on seeds’ germination and seedlings’ growth of mung bean using hydroponic culture. We designed 7 different level of each ion concentration, as follows, 15mg/L, 30mg/L, 45mg/L, 90mg/L, 60mg/L, and 120mg/L, 150mg/L, each compared to distillate. As the result showed that under the same concentration, mercury ion’s toxicity to mung bean was more than chromate ion’s, which did more harm to mung bean in all physiological indexes. However, with the same ion at different concentrations, generally as follows, low concentration contributes to mung beans’ growth, and middle to high concentration inhibits it growth, while higher concentration kills the young plants directly. We found that with mercury ion’s concentration over 60mg/L, the beans got significantly great damage, leading to seedlings’ withering. Under the condition that the mercury ion stress concentration at 150mg/L, seven days later, which lead to mung bean seedlings dead all. With the same ions concentrations of chrome, seedlings grew well. It can be seen that, mercury ion’s toxicity at beans is more than chromate ion’s. As the following morphological index, biochemical index and resistance index concerned, mercury ion in a single stress concentration of liquid below 45mg/L contributed to seeds’ germination and seedlings’ multiple indexes, and 30mg/L seems to be the best, to get the equivalent result. Chromium ion single stress concentration of liquid corresponded below 60mg/L and at 45mg/L. However, we found that mercury ion’s influence on mung bean seedlings’ SOD declined first, then rose and went down at last, and the influence got down with the concentration at 15mg/L. Possibly reason is that the mercury ion’s toxicity on mung bean seedlings is greater than others. Mercury ion influenced mung beans’ body at the very beginnings, causing seedlings’ resistance at some level after seven days. It resulted some differences from other experiments.

Key words : Hg2+; Cr3+; stress; Mung bean;