• ISSN 1008-505X
  • CN 11-3996/S
张金尧, 宋书会, 郭伟, 徐芳森, 汪洪. 激光剥蚀–电感耦合等离子体质谱分析缺锌胁迫玉米根尖微量元素空间分布[J]. 植物营养与肥料学报, 2019, 25(10): 1737-1742. DOI: 10.11674/zwyf.18426
引用本文: 张金尧, 宋书会, 郭伟, 徐芳森, 汪洪. 激光剥蚀–电感耦合等离子体质谱分析缺锌胁迫玉米根尖微量元素空间分布[J]. 植物营养与肥料学报, 2019, 25(10): 1737-1742. DOI: 10.11674/zwyf.18426
ZHANG Jin-yao, SONG Shu-hui, GUO Wei, XU Fang-sen, WANG Hong. Distribution of trace metals in maize (Zea mays L.) root tips under zinc deficiency using laser ablation inductively coupled plasma mass spectrometry[J]. Journal of Plant Nutrition and Fertilizers, 2019, 25(10): 1737-1742. DOI: 10.11674/zwyf.18426
Citation: ZHANG Jin-yao, SONG Shu-hui, GUO Wei, XU Fang-sen, WANG Hong. Distribution of trace metals in maize (Zea mays L.) root tips under zinc deficiency using laser ablation inductively coupled plasma mass spectrometry[J]. Journal of Plant Nutrition and Fertilizers, 2019, 25(10): 1737-1742. DOI: 10.11674/zwyf.18426

激光剥蚀–电感耦合等离子体质谱分析缺锌胁迫玉米根尖微量元素空间分布

Distribution of trace metals in maize (Zea mays L.) root tips under zinc deficiency using laser ablation inductively coupled plasma mass spectrometry

  • 摘要:
    目的 激光剥蚀−电感耦合等离子体质谱 (laser ablation inductively coupled plasma mass spectrometry,LA-ICP-MS) 法是一种利用聚焦激光扫描激发固体样品,并经电感耦合等离子体质谱离子化,以分析样品元素含量及分布的新兴技术。本文利用LA-ICP-MS技术研究缺锌 (Zn) 胁迫下玉米根尖铁 (Fe)、锰 (Mn)、铜 (Cu)、Zn元素的分布定位,以期从组织水平揭示作物中Zn的转运富集规律及缺Zn对微量金属元素吸收转运的影响。
    方法 以玉米‘郑单958’为试材,用不同加锌浓度营养液进行培养,获得根系样品烘干后磨碎、混匀、压片,取适量混匀的根系样品消煮,利用液体进样系统ICP-MS检测得到样品中实际元素含量,并与样品压片LA-ICP-MS检测信号值间进行线性回归分析,标准曲线相关性良好 (R2 = 0.9995),从而获得可适用于LA-ICP-MS定量分析的自制根系标准样品。将此标准样品与待测根尖样品放入LA样品池中,13C作为内标元素,进行缺锌胁迫下玉米根尖中锌元素分布特征的定量成像研究。
    结果 缺锌胁迫下玉米根系锌元素含量显著降低,仅为正常植株的27.78%;缺锌根系中Mn和Cu含量升高。LA-ICP-MS系统定量成像显示,玉米根尖顶端Zn含量较高,由表皮向内锌含量逐渐增加;缺Zn处理根系Zn含量降低,根尖顶端Zn分布明显减少。利用LA-ICP-MS检测信号强度值对Fe、Mn、Cu元素进行定性分布,成像显示在正常根系中Fe、Mn、Cu元素在根尖前端信号强度较高,由表向内逐渐增加;缺锌处理下,根系中Fe、Mn、Cu信号强度均有不同程度增加。
    结论 正常施锌玉米根尖中锌、铁、锰、铜分布呈现由表皮向中柱增加的趋势;缺锌胁迫下根系锌含量显著降低,铁、锰、铜均有不同程度积累。

     

    Abstract:
    Objectives Laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS) is an emerging technology to detect content and distribution of elements in plants. We presented the distribution of iron (Fe), manganese (Mn), copper (Cu), and zinc (Zn) in maize root tips under Zn-deficiency, using LA-ICP-MS to reveal the mechanism of transport and enrichment of Zn in crops and the effect of Zn deficiency on the absorption and transport of trace metal elements at the tissue level.
    Methods Zea mays L. cv. ZD958 was used as the test crop. The hydroponic culture experiment was conducted using different concentrations of zinc (Zn) treatments. 15-day Zn treated roots were harvested, dried, ground, and homogenized. Part of the dry root samples were digested with HNO3 and Zn concentration in the digesting solution was determined using ICP-MS with a liquid injection sample system. The rest of the root sample powders was compressed to the discs as the standard for LA-ICP-MS. The good linear correlation (R2 = 0.9995) was obtained between the actual Zn concentration of the standard of root discs and the signal intensity detected by LA-ICP-MS, indicating that the self-made root standard discs could be used for LA-ICP-MS quantitative analysis. The tested root tips of maize and the standard discs were placed in the LA sample cell for the measurement. 13C was used as an internal standard element to compensate for the difference in the amount of the ablated materials. The quantitative image was obtained to study Zn, Fe, Mn and Cu distribution in the root tips of maize under Zn deficiency.
    Results The Zn content in maize roots decreased significantly under Zn deficiency, which was only 27.78% of that in normal roots, while the contents of Mn and Cu increased in Zn-deficient roots. The imaging of LA-ICP-MS showed the Zn content was higher in root tips and increased gradually inward from the epidermis, while the content of Zn decreased in Zn-deficient roots, especially in apex of root tips. In addition, the signal intensity of Fe, Mn and Cu detected by LA-ICP-MS showed qualitative distribution. The signal intensities of Fe, Mn and Cu were higher in the apex of Zn-sufficient root tips, increasing inward from the surface gradually, and which were increased to different degrees in maize roots under Zn-deficiency.
    Conclusions The Zn, Fe, Mn, and Cu contents increased from epidermis to the cortex in the root tip of normal maize. However, the contents of Fe, Mn and Cu increased in Zn-deficient root tips.

     

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