Silva Junior E C, Wadt L H O, Silva K E, Lima R M B, Batista K D, Guedes M C, Carvalho G S, Carvalho T S, Reis A R, Lopes G, Guilherme L R G
Department of Soil Science, Federal University of Lavras, Lavras, MG, CEP: 37200-000, Brazil.
Embrapa Rondônia, Porto Velho, RO, CEP: 76815-800, Brazil.
Chemosphere. 2017 Dec;188:650-658. doi: 10.1016/j.chemosphere.2017.08.158. Epub 2017 Sep 4.
Brazil nut tree (Bertholletia excelsa) is native of the Amazon rainforest. Brazil nuts are consumed worldwide and are known as the richest food source of selenium (Se). Yet, the reasoning for such Se contents is not well stablished. We evaluated the variation in Se concentration of Brazil nuts from Brazilian Amazon basin, as well as soil properties, including total Se concentration, of the soils sampled directly underneath the trees crown, aiming to investigate which soil properties influence Se accumulation in the nuts. The median Se concentration in Brazil nuts varied from 2.07 mg kg (in Mato Grosso state) to 68.15 mg kg (in Amazonas state). Therefore, depending on its origin, a single Brazil nut could provide from 11% (in the Mato Grosso state) up to 288% (in the Amazonas state) of the daily Se requirement for an adult man (70 μg). The total Se concentration in the soil also varied considerably, ranging from <65.76 to 625.91 μg kg, with highest Se concentrations being observed in soil samples from the state of Amazonas. Se accumulation in Brazil nuts generally increased in soils with higher total Se content, but decreased under acidic conditions in the soil. This indicates that, besides total soil Se concentration, soil acidity plays a major role in Se uptake by Brazil nut trees, possibly due to the importance of this soil property to Se retention in the soil.
巴西坚果（Bertholletia excelsa）原产于亚马逊雨林。巴西坚果在全球范围内都有食用，并且是已知最富含硒（Se）的食物来源。然而，这种高硒含量的原因尚未完全明确。我们评估了巴西亚马逊流域巴西坚果中硒浓度的变化，以及直接在树冠下方采集的土壤样本的性质，包括总硒浓度，旨在研究哪些土壤性质会影响坚果中硒的积累。巴西坚果中硒浓度的中位数从2.07毫克/千克（在马托格罗索州）到68.15毫克/千克（在亚马逊州）不等。因此，根据其产地不同，一颗巴西坚果可为成年男性（70微克）提供每日硒需求量的11%（在马托格罗索州）至288%（在亚马逊州）。土壤中的总硒浓度也有很大差异，范围从<65.76至625.91微克/千克，其中在亚马逊州采集的土壤样本中观察到最高的硒浓度。巴西坚果中的硒积累通常在总硒含量较高的土壤中增加，但在土壤酸性条件下会减少。这表明，除了土壤总硒浓度外，土壤酸度在巴西坚果对硒的吸收中也起着重要作用，这可能是因为这种土壤性质对土壤中硒的保留很重要。
