镉(Cd)是毒性最强的重金属元素之一，具有稳定、积累和不易消除等特性，进入土壤环境中易被植物吸收，并可通过食物链进入人体，在人体内不断积累，严重威胁人体健康及生命安全。植物修复技术(Phytoremediation)是近年来发展起来的一种主要用于清除土壤重金属污染的绿色生态技术。植物修复技术的核心是找到超富集植物(Hyperaccumulator)，但现已知的超富集植物往往存在生物量低、生长缓慢、地域性较强和修复时间较长等缺陷，且研究对象多集中矿区及草本植物，而对木本植物的研究甚少，因此有必要针对这一问题开展相关研究以丰富超富集植物的种类。为此，本文采用水培和土培相结合的试验方法，研究木本植物忍冬Lonicera japonica Thunb.对不同浓度镉(Cd)的生长响应及积累特性。结果表明：不同浓度的Cd处理对忍冬的生长并未造成毒害症状，表现为其根部和地上部生物量与对照相比并无显著差异。无论水培还是土培生长条件下，在较高浓度的Cd处理下，忍冬仍能保持正常生长，表现出很好的耐性。在水培条件下，当营养液中Cd处理浓度为25 mg·L-1时，忍冬地上部中Cd含量接近300.00μg·g-1；而在土培条件下，当土壤中Cd处理浓度为50 mg·kg-1时，其地上部中Cd含量仍远远高于Cd超富集植物的临界含量标准，即地上部分富集Cd超过100μg·g-1，且其具有较高的耐性系数（index of tolerance，IT均超过0.80）和富集系数（bioaccumulation factor，BF均远超过1.00），这表明忍冬具备了Cd超富集植物的特征，是一种新发现的Cd超富集植物，将其应用于Cd污染土壤修复具有重要的现实意义。%Cadmium (Cd) is one of the most toxic heavy metal elements, which is stable, accumulated and uneasy to eliminate, easily absorbed by plants in the soil environment. Cd can enter the body through the food chain, continue to accumulate in the body, and cause a serious threat to human health and life safety. Phytoremediation has been considered as a green ecological technology in recent years, which is mainly used for removal of heavy metal contaminated soils. The core of phytoremediation technology is to find the hyperaccumulators, but now known hyperaccumulators are often low biomass, slow growth, strong geographical distribution and long remediation period. At the same time, many studies focus on plants in mining area and herbs, and little informantion on woody plants, so it is necessary to do the related study and enrich the hyperaccumulator species. Therefore, the growth responses and accumulation characteristics of Lonicera japonica Thunb. to different concentrations cadmium (Cd) were investigated under nutrient and soil mediums. The results showed that different concentration Cd had no toxic impact on the growth of L. japonica, indicated by the biomass of roots and shoots had no significant difference compared with the control. Regardless of nutrient or soil culture conditions, under higher concentration Cd stress, L. japonica still could keep normal growth, which showed a good tolerance. In nutrient culture conditions, when the Cd concentration in the medium was 25 mg·L-1, Cd contents of the shoots were nearly 300 μg·g-1 Cd, and in soil culture conditions, when the Cd concentration in the medium was 50 mg·kg-1, Cd contents of the shoots were more than 100 μg·g-1 Cd which is much higher than the critical content standards for Cd hyperaccumulaor, and had the high index of tolerance (IT all above 0.80)and bioaccumulation factor (BF all above 1.00), which indicated that L. japonica has the characteristics of Cd hyperaccumulator and becomes a newly discovered Cd hyperaccumulator. It would have important practical significance to phytoremediate Cd-contaminated soil by L. japonica.
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