植物修复法是重金属污染场地修复的重要手段, 这种“绿色修复技术”得到了学者们的广泛关注和期待。 在重金属胁迫条件下, 植物自身会出现相应的响应反映, 进而逐渐适应并有效减缓重金属的直接毒害作用。 这种微尺度的调控行为往往多维度和不可见, 需要借助精密仪器分析技术加以剖析。 现阶段, 相关方面的研究还略显欠缺。 以黄土修复植物金盏菊幼苗为研究对象, 分析Pb/Cd复合胁迫对其表观形貌的影响, 采用傅里叶变换红外光谱法（FTIR）识别其地下和地上部分样本的官能团性质, 初步推断金盏菊对Pb/Cd胁迫的响应途径和耐受机制。 研究表明: 随着Pb/Cd胁迫程度的加剧, 金盏菊根冠弯曲萎缩, 根毛数量明显减少, 而其地上部分形貌差异很小。 Pb/Cd胁迫对金盏菊幼苗地下和地上部分的FTIR图谱影响较大: 3 573 cm-1附近的—OH峰强减弱且发生移动, 随着Pb/Cd胁迫浓度的增加, 峰形更趋复杂化; 这表明Pb/Cd与—OH间存在配位结合效应, Pb/Cd胁迫干扰了有机物的合成和分泌。 饱和C—H振动峰整体红移, 可能与细胞膜的膜脂氧化程度有关。 1 631和1 574 cm-1处吸收峰强下降, 说明与之关联的蛋白质组分特性可能有异。 1 385 cm-1处峰位有所偏移, 推测金盏菊通过改变果胶质和油脂的甲基化程度, 完成细胞组织对Pb/Cd胁迫的“直接排斥→逐步适应→增强抗逆性”的过程转变。 FTIR对于识别土壤重金属的植物修复机制具有重要指导意义。

As an environmentally-friendly technology attracting great attention from current researchers, phytoremediation is significant for site remediation contaminated by heavy metals. The plant will appear related physiological response to reduce direct harm caused by the stress of heavy metals. The microscale behavior is always multi-dimensional and difficult to detect. The advanced instruments are effective to resolve the scientific issues, while the related researches are seldom investigated. Taking calendula officinalis seedlings as experimental samples, scanning electron microscope (SEM) and Fourier transform infrared spectroscopy (FT-IR) were applied to compare the surface characteristics and functional groups variation, respectively. The response process and tolerance mechanism of calendula officinalis seedlings to lead and cadmium stress were further analyzed. The results showed: with the increasing concentration of lead and cadmium in loess, the calyptra of calendula officinalis seedlings become bending and wilting; the amount of root hairs decreases greatly while no significant variations of aerial parts are found on surface characteristics. The stress of lead and cadmium are responsible for the difference of FTIR spectra of Calendula officinalis seedlings. The peak absorbance at 3 573 cm-1 decreases and the peak becomes more complex with the increasing contents of lead and cadmium. It might be the coordination effect between lead/cadmium and hydroxyl, which affects the synthesis and secretion of organic matters. The movement of C—H vibration peak is associated with the lipid oxidationwhile the changes at 1 631 and 1 574 cm-1 suggest the protein component differences. The shifting peak at 1 385 cm-1 might be associated with the methylation of pectin and lipid, and the behavior is positive for the adaption process of calendula officinalis seedlings to lead and cadmium stress. The FTIR spectra are effective to reveal the phytoremediation mechanism on heavy metals contamination in pedosphere.