Maize is one of the most important cereal crop species due to its uses for human and cattle nourishment, as well as its industrial use as a raw material. The yield and grain quality of maize depend on plant establishment, which starts with germination. Germination is dependent on embryo vigor and the stored reserves in the scutellum and endosperm. During germination, the scutellum epidermis changes and secretes enzymes and hormones into the endosperm. As a result, the hydrolysis products of the reserves and the different soluble nutrients are translocated to the scutellum through epithelial cells. Then, the reserves are directed to the embryo axis to sustain its growth. Therefore, the microenvironment surrounding the scutellum modulates its function. Zinc (Zn) is a micronutrient stored in the maize scutellum and endosperm; during imbibition, Zn from the endosperm is solubilized and mobilized towards the scutellum. During this process, Zn first becomes concentrated and interacts with cell wall charges, after which excess Zn is internalized in the vacuole. Currently, the effect of high Zn concentrations on the scutellum function and germinative processes are not known. In this paper, we show that, as a function of the concentration and time of exposure, Zn causes decreases in the radicle and plumule lengths and promotes the accumulation of reactive oxygen species (ROS) and flavonoids as well as changes in the activity of the cell wall Class III peroxidase (POD), which was quantified with guaiacol or catechin in the presence of H₂O₂. The relationship between the activity index or proportion of POD activity in the scutellum and the changes in the flavonoid concentration is proposed as a marker of stress and the state of vigor of the embryo.

中文翻译：

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过量的锌改变玉米盾片中细胞壁III类过氧化物酶活性和类黄酮含量

玉米是最重要的谷类作物品种之一，因为它可用于人类和牛的营养，以及作为原料的工业用途。玉米的产量和谷物品质取决于植物的生长，而植物的生长始于发芽。发芽取决于胚胎的活力以及在盾片和胚乳中储存的储备。在发芽过程中，盾片表皮发生变化，并向胚乳分泌酶和激素。结果，储备的水解产物和不同的可溶性营养素通过上皮细胞转移至盾片。然后，将储备物引导至胚轴以维持其生长。因此，盾片周围的微环境调节其功能。锌是储存在玉米盾片和胚乳中的微量营养素。在吸水期间 胚乳中的锌被溶解并转移到盾片上。在此过程中，Zn首先浓缩并与细胞壁电荷相互作用，此后多余的Zn被内在液泡中。目前，尚不清楚高锌浓度对盾片功能和发芽过程的影响。在本文中，我们表明，作为浓度和暴露时间的函数，Zn引起胚根和胚芽长度的减少，并促进了活性氧（ROS）和类黄酮的积累以及活性的变化。细胞壁III类过氧化物酶（POD），在H存在下用愈创木酚或儿茶素定量 之后，多余的Zn被内在液泡中。目前，尚不清楚高锌浓度对盾片功能和发芽过程的影响。在本文中，我们表明，作为浓度和暴露时间的函数，Zn引起胚根和胚芽长度的减少，并促进了活性氧（ROS）和类黄酮的积累以及活性的变化。细胞壁III类过氧化物酶（POD），在H存在下用愈创木酚或儿茶素定量 之后，多余的Zn被内在液泡中。目前，尚不清楚高锌浓度对盾片功能和发芽过程的影响。在本文中，我们表明，作为浓度和暴露时间的函数，Zn引起胚根和胚芽长度的减少，并促进了活性氧（ROS）和类黄酮的积累以及活性的变化。细胞壁III类过氧化物酶（POD），在H存在下用愈创木酚或儿茶素定量₂ O ₂。提出盾片中活性指数或POD活性比例与类黄酮浓度变化之间的关系可作为应激和胚胎活力状态的标志。