Background and Aim

Success in agronomic biofortification of maize and wheat is highly variable. This study aimed to elucidate the differences in uptake and translocation of foliar-applied zinc (Zn) in maize (Zea mays L.) and wheat (Triticum aestivum L.) using different experimental approaches.

Methods

Old leaves of plants cultured with low or adequate Zn supply in soil were treated with natural Zn (as ZnSO₄) or enriched stable isotope ⁷⁰Zn as SO₄ salt. Treated leaves, and the remaining untreated shoot and roots were analyzed for Zn using quantitative (ICP-OES and ICP-MS after acid digestion) and qualitative (fluorescence microscopy after Zinpyr-1 staining) techniques.

Results

Application of Zn to a single old leaf resulted in significantly higher increments in Zn concentration of the treated leaf, remaining untreated shoot and roots in wheat than in maize, particularly under low Zn supply. The relative Zn uptake (i.e., the portion of ⁷⁰Zn taken up by the treated leaf) was also estimated to be significantly higher in wheat than maize, irrespective of the rate of Zn supply to plants. Higher uptake and translocation of Zn in wheat compared to maize was also visualized and demonstrated by using Zinpyr-1 fluorescent dye.

Conclusions

Our results conclude that wheat is superior to maize in terms of leaf penetration and uptake, as well as subsequent translocation of foliar-applied Zn, therefore, the agronomic biofortification potential is better for wheat than for maize.

中文翻译：

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玉米和小麦叶片施用锌的吸收和转运差异

背景与目标

玉米和小麦在农艺生物强化方面的成功是高度可变的。这项研究旨在阐明采用不同的实验方法，玉米（Zea mays L.）和小麦（Triticum aestivum L.）中叶面施用锌（Zn）的吸收和转运的差异。

方法

土壤中锌供应低或充足的植物的老叶用天然锌（如ZnSO ₄）或富含稳定同位素⁷⁰锌的SO ₄盐处理。使用定量（酸消解后的ICP-OES和ICP-MS）和定性（Zinpyr-1染色后的荧光显微镜）技术分析处理过的叶子以及其余未处理的芽和根中的锌。

结果

锌在单片老叶上的施用导致小麦中锌浓度的增量显着更高，其余未处理的芽和根比玉米中的高，尤其是在锌供应低的情况下。估计相对的锌吸收量（即，处理过的叶片吸收的⁷⁰ Zn的比例）在小麦中也显着高于玉米，而与植物中锌的供应量无关。通过使用Zinpyr-1荧光染料，还可以观察到并证明与玉米相比，小麦中锌的吸收和转运更高。

结论

我们的结果得出结论，就叶片的渗透和吸收以及随后叶面施用的锌的转运而言，小麦优于玉米，因此，小麦的农艺生物强化潜力要比玉米好。