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首页> 外文期刊>Journal of Environmental Science and Health. A, Toxic/Hazardous Substances & Environmental Engineering >Characteristics of Cadmium Uptake and Accumulation by Two Contrasting Ecotypes of Sedum alfredii Hance
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Characteristics of Cadmium Uptake and Accumulation by Two Contrasting Ecotypes of Sedum alfredii Hance

机译：两种不同景天景天对镉的吸收和积累特征

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The mined ecotype of Sedum alfredii Hance has been identified to be a zinc (Zn) hyperaccumulator native to China. In the present article, the characteristics of cadmium (Cd) uptake and accumulation were compared with hydroponic experiments between the mined and the nonmined ecotypes of Sedum alfredii Hance. The results indicate that the plants of the mined ecotype (ME) have higher tolerance of Cd than the plants of the nonmined ecotypes (NME) in terms of dry matter yield. The thresholds of external Cd levels for the reduction of plant growth were 100 μmol L~(-1) for the NME and 400 μmol L~(-1) for the ME, respectively. Kinetic study showed that the rates of Cd influx into roots (IR) and transport to shoots (TR) were higher in the ME than in the NME, with 5-fold higher for the maximum IR (I_(max)) and 13-fold higher for the maximum TR (T_(max)) in the NME, respectively. Cadmium concentrations increased with increasing external Cd supply levels. Root Cd concentrations in the NME were higher than that in the ME, with a maximum being 5646 mg kg-1 for the NME and 2889 mg kg-1 for the ME at 1000 μmol L-1 Cd. On the contrary, shoot Cd concentrations of the NME were far lower than that of the ME. Maximum shoot Cd concentrations were 533 mg kg-1 in leaves and 935 mg kg-1 in stems at 1000 μmol L-1 Cd for NME, whereas, 4933 and 3874 mg kg-1 at 400 μmol L-1 Cd for the ME, respectively. Meanwhile, Cd concentrations in the shoots of both the NME and ME increased with advancing Cd treatment time. At 100 μmolL-1 Cd, concentrations of Cd in leaves and stems of the NME sharply increased within initial 8 and 12 days, and those in the ME increased dramatically until D20 and D16, respectively. However, leaf and stem Cd concentrations reached their maximum values on D4 for the NME and D8 for the ME, respectively, when the plants were exposed to 1 μmol L-1 Cd. Cadmium accumulation by plant shoots was obvious higher in the ME than in the NME at varied Cd supply levels or Cd treatment time. The maximum Cd taken up by the shoots was 1032 μg plant-1 in concentration-dependent uptake, and 1699 μg plant-1 in time-course uptake for the ME, with 15-fold and 18-fold higher than those for the NME, respectively. The ratios of shoot/root of Cd ranged from 12 to 39, varying with Cd supply levels, and from 13 to 24 in the varied treatment times for the ME, more than 10 times greater than those for the NME. In addition, Cd distribution in leaves, stems and roots of ME was greatly different from those of NME. The percentage of Cd distribution in shoots was more than 79 at the varied Cd supply levels, or 83 in the varied treatment time for ME, both higher than that for NME. It could be concluded that the mined ecotype of Sedum alfredii Hance has a greater ability to tolerate, transport, and accumulate Cd, as compared with the nonmined ecotype.
机译：景天景天的开采生态型已被确定为中国本土的锌（Zn）超蓄积体。在本文中，比较了矿产和非矿产东南景天景天对镉（Cd）的吸收和积累特征，并与水培试验进行了比较。结果表明，就干物质产量而言，开采生态型（ME）的植物对镉的耐受性高于未开采生态型（NME）的植物。降低植物生长的外部镉水平的阈值分别为：NME为100μmolL〜（-1），ME为400μmolL〜（-1）。动力学研究表明，ME中的Cd流入根部（IR）和转运到枝条（TR）的速率高于NME，最大IR（I_（max））的5倍和13倍的高。 NME中的最大TR（T_（max））分别更高。镉的浓度随着外部Cd供应量的增加而增加。 NME中的根Cd浓度高于ME中的浓度，在1000μmolL-1 Cd下，NME的最大Cd浓度为5646 mg kg-1，ME的最大Cd浓度为2889 mg kg-1。相反，NME的芽Cd浓度远低于ME。对于NME，在1000μmolL-1 Cd下，茎叶中Cd的最大浓度为533 mg kg-1，在茎中为935 mg kg-1，而对于ME，在400μmolL-1 Cd下，茎中的最大Cd浓度为4933和3874 mg kg-1。分别。同时，NME和ME的芽中Cd浓度随着Cd处理时间的增加而增加。在100μmolL-1Cd下，NME叶片和茎中的Cd浓度在开始的8天和12天之内急剧增加，而ME中的Cd浓度则急剧增加，直到D20和D16。但是，当植物暴露于1μmolL-1 Cd时，叶子和茎中Cd的浓度分别在NME的D4和ME的D8达到最大值。在不同的镉供应水平或镉处理时间下，ME中植物芽的镉积累明显高于NME。 ME吸收的最大镉量为1032μgplant-1，随时间变化的吸收量为1699μgplant-1，比NME高15倍和18倍，分别。 Cd的根冠比/根比在12至39之间，随Cd的供应水平而变化，在ME的不同处理时间内，其Cd的根/根比为13至24，比NME大10倍以上。另外，镉在ME的叶，茎和根中的分布与NME有很大的不同。在不同的镉供应水平下，芽中Cd分布的百分比大于79，而在ME的不同处理时间中，镉的分布百分比大于83，均高于NME。可以得出结论，与未开采的生态型相比，东南景天的采掘生态型具有更大的耐受，运输和积累镉的能力。

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