Soil waterlogging is a common problem in some agricultural areas, including regions under soybean (Glycine max) cultivation. In waterlogged soils, soil O₂ depletion occurs due to aerobic microorganisms and plants, affecting the metabolic and physiological processes of plants after suffering anoxia in their root tissue. Another harmful factor in this situation is the exponential increase in the availability of iron (Fe) in the soil, which may result in absorption of excess Fe. The present study sought to evaluate the response mechanisms in soybean leaves ‘Agroeste 3680’ by physiological and biochemical analyses associating them with the development of pods in non-waterlogged and waterlogged soil, combined with one moderate and two toxic levels of Fe. Gas exchange was strongly affected by soil waterlogging. Excess Fe without soil waterlogging reduced photosynthetic pigments, and potentiated this reduction when associated with soil waterlogging. Starch and ureide accumulation in the first newly expanded trifoliate leaves proved to be response mechanisms induced by soil waterlogging and excess Fe, since plants cultivated under soil non-waterlogged soil at 25 mg dm⁻³ Fe showed lower contents when compared to stressed plants. Thus, starch and ureide accumulation could be considered efficient biomarkers of phytotoxicity caused by soil waterlogging and excess Fe in soybean plants. The reproductive development was abruptly interrupted by the imposition of stresses, leading to a loss of pod dry biomass, which was largely due to the substantial decrease in the net photosynthetic rate, as expressed by area (A), the blockage of carbohydrate transport to sink tissues and an increase of malondialdehyde (MDA). The negative effect on reproductive development was more pronounced under waterlogged soil.

中文翻译：

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大豆对生殖期铁过量引起的土壤涝渍的响应。

土壤涝渍是一些农业地区的常见问题，包括种植大豆（Glycine max）的地区。在淹水土壤中，土壤 O ₂由于需氧微生物和植物发生耗竭，影响植物根组织缺氧后的代谢和生理过程。这种情况下的另一个有害因素是土壤中铁 (Fe) 的可用性呈指数增长，这可能导致吸收过量的铁。本研究试图通过生理和生化分析来评估大豆叶片 'Agroeste 3680' 的响应机制，将它们与非淹水和淹水土壤中豆荚的发育相关联，并结合一种中等水平和两种毒性水平的 Fe。土壤涝渍严重影响气体交换。没有土壤涝渍的过量 Fe 会减少光合色素，并在与土壤涝渍相关时加强这种减少。与受胁迫的植物相比，^-3 Fe 显示出较低的含量。因此，淀粉和脲化物的积累可以被认为是大豆植物中土壤涝渍和过量铁引起的植物毒性的有效生物标志物。生殖发育被施加的压力突然中断，导致豆荚干生物量的损失，这主要是由于净光合速率的大幅下降，如面积（A）所示，碳水化合物运输到下沉的障碍组织和丙二醛（MDA）的增加。在淹水土壤下对生殖发育的负面影响更为明显。