镉胁迫对黑杨派无性系生物量及镉离子含量的影响

  目的  研究重金属镉（Cd）对黑杨派无性系生物量及镉离子含量的影响，探讨无性系对Cd胁迫的响应机制，为治理日渐严重的土壤重金属污染治理提供依据。  方法  对黑杨派的5个无性系进行沙培试验，分别测定其生长量、不同器官生物量及Cd2+ 含量，评价不同无性系抗Cd胁迫的能力。  结果  随着Cd2+ 质量浓度增加，胁迫后苗高与地径均呈下降趋势，各无性系苗高性状较地径对Cd胁迫更为敏感；胁迫后叶片数量整体呈下降趋势。通过对不同无性系叶片生物量均值分析发现，无性系I-107、L-35、中菏1号排在前3位，除15 mg/L Cd2+ 质量浓度外，在其他质量浓度胁迫下差异均达显著水平。随着Cd2+ 质量浓度增加，不同无性系茎生物量与根生物量变化趋势一致，整体先降低，后升高再降低。对不同质量浓度Cd2+ 胁迫下茎与根生物量的均值进行分析，发现无性系I-107、鲁林9号、L-35的茎生物量排在前3位，I-107、鲁林16号、L-35的根生物量排在前3位。各无性系茎中Cd2+ 含量随Cd2+ 质量浓度的增加均有不同程度升高，其中无性系I-107较对照增长率最大，其次为鲁林9号。在最高质量浓度胁迫下，鲁林9号的茎中Cd2+ 含量较其他无性系差异达显著水平。不同无性系叶片和根中Cd2+ 含量随质量浓度增加均有不同程度升高，在最高质量浓度胁迫下，无性系I-107、中菏1号、鲁林9号中叶片Cd2+ 含量较对照增长率排在前3位。无性系中菏1号、I-107、L-35中根Cd2+ 含量较对照增长率排在前3位。总生物量呈先升高再降低的趋势，总Cd2+ 含量呈先升高再降低再升高的趋势。  结论  利用主成分分析对5个无性系生长量、生物量及Cd2+ 含量进行综合评价，发现无性系I-107、鲁林9号和L-35的抗重金属Cd能力较强，可为重金属Cd污染土壤的治理与修复提供试验材料。 

Effects of cadmium stress on biomass and cadmium ion content of Sect. Aigeiros clones

  Objective  In order to study the effects of heavy metal stress on biomass and cadmiumion content of Sect. Aigeiros clones, the response mechanism of clones to Cd stress was discussed, which provided a theoretical basis for the increasingly serious soil heavy metal pollution problem.  Method  Sand culture experiments were carried out on five Sect. Aigeiros clones, growth, biomass and cadmium content of different organs were measured to evaluate the resistance of different clones to Cd stress.  Result  With the increase of Cd2+ mass concentration, the seedling height and ground diameter decreased under Cd stress, the height traits of tested clones were more sensitive to Cd stress than the ground diameter; the number of leaves decreased after Cd stress. Based on the analysis of the mean value of leaf biomass of different clones, it was found that clones ‘I-107’ , ‘L-35’ and ‘Zhonghe 1’ were in the top three, except for the mass concentration of Cd2+ being 15mg/L, the difference was significant under other mass concentrations. With the increase of Cd2+ mass concentration, the variation trend of stem biomass and root biomass of different clones was the same, the whole trend was first decreased, then increased and then decreased. The average of stem and root biomass under different mass concentrations of Cd stress were analyzed, the stem biomass of ‘I-107’ , ‘Lulin 9’ and ‘L-35’ were in the top three, and the root biomass of ‘ I-107’, ‘Lulin 16’ and ‘L-35’ were in the top three. The Cd content in stems of different clones increased with the increase of Cd2+ mass concentration, and ‘I-107’had the highest growth rate compared with the control, followed by ‘Lulin 9’. Under the highest mass concentration, the difference between ‘Lulin 9’and other clones was significant. The Cd content in leaves and roots of different clones increased with the increase of Cd2+ mass concentration. Under the highest mass concentration, the content of Cd2+ in the leaves of ‘I-107’ , ‘Zhonghe 1’ and ‘Lulin 9’ was in the top three compared with the growth rate of the control; and the content of Cd2+ in roots of ‘Zhonghe 1’,‘I-107’and ‘L-35’ was in the top three compared with the growth rate of control. The total biomass increased first and then decreased; the total Cd content increased first, then decreased and then increased.  Conclusion  The growth, biomass and Cd content of five clones were comprehensively evaluated by principal component analysis, ‘I-107’ ,‘Lulin 9’ and ‘L-35’ had strong resistance to Cd, which could be used as ideal clones for remediation of cadmium-contaminated soils.