In the present study, we investigated the sites of aluminum (Al) accumulation and its effects on the growth, morphology and nutritional status in root tips of soybean ( Glycine max L.) genotype Conquista. The seedlings were exposed to nutrient Clark solution, pH 4.0, with 0 (control) and 100 µM of Al for 24, 48 and 72 h. Our results showed an Al accumulation in the superficial layers of the root tip, such as the root cap cells, epidermis and cortex cells, and internally in the cell walls of the meristematic cells. The Al accumulation in the outer cells prevented the entry of this metal in the inner tissues. However, scanning electron micrographs showed damage in the external micromorphology of the root tips. This damage resulted in cellular disorganization in the root cap and epidermis cells leading to a reduction in Ca and Mg uptake. Despite that, there was no change in root growth. Taken together, our findings suggest that genotype Conquista has a capacity to avoid Al toxicity, probably by Al immobilization in the cell walls and in the external tissues of the root tip.

中文翻译：

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大豆幼苗根尖铝的差异积累

在本研究中，我们研究了铝 (Al) 积累的位点及其对大豆 (Glycine max L.) 基因型 Conquista 根尖生长、形态和营养状况的影响。将幼苗暴露于 pH 4.0、0（对照）和 100 µM 铝的营养克拉克溶液中 24、48 和 72 小时。我们的结果表明，铝在根尖的表层，如根帽细胞、表皮和皮质细胞，以及分生组织细胞的细胞壁内部积累。外部细胞中的铝积累阻止了这种金属进入内部组织。然而，扫描电子显微照片显示根尖的外部微形态受损。这种损伤导致根帽和表皮细胞中的细胞解体，导致钙和镁吸收减少。尽管那样，根系生长没有变化。综上所述，我们的研究结果表明，基因型 Conquista 具有避免铝毒性的能力，可能是通过将铝固定在细胞壁和根尖外部组织中。