College of Life Sciences, Nanjing Agricultural University, Nanjing 210095, PR China; Provincial Key Laboratory of Agrobiology, Institute of Food Crops, Jiangsu Academy of Agricultural Sciences, Nanjing 210014, PR China; The UWA Institute of Agriculture, and UWA School of Agriculture and Environment, The University of Western Australia, Perth, WA 6009, Australia.
College of Life Sciences, Nanjing Agricultural University, Nanjing 210095, PR China.
Sci Total Environ. 2019 Jun 1;667:532-539. doi: 10.1016/j.scitotenv.2019.02.394. Epub 2019 Feb 26.
Arsenic (As) and cadmium (Cd) are known to be toxic to humans, and elevated concentrations have been documented in food crops worldwide. However, little is known regarding their uptake, translocation, and distribution in wheat plants during plant development. A series of experiments were conducted to investigate the spatial distribution and dynamics of As and Cd in two wheat cultivars (cv. JN12 and JM85; the latter is a low grain Cd accumulator) at different developmental stages. Root concentrations of As decreased by 84%, and those of Cd by 67%, from tillering to maturity. In contrast, As concentrations in the stems increased 3.1-fold. A significant decrease in root As accumulation was observed at the mature stage, whereas root Cd accumulation decreased largely at the elongation stage. The concentrations of Cd in all leaves and As in new leaves increased as plant growth advanced. However, As concentrations in old leaves decreased significantly from grain filling to maturity. In both cultivars, the upward transfer toward younger parts of shoots was greater in the case of Cd than of As. The remobilization of As and Cd from stems and roots differed between the two cultivars. Arsenic concentrations in rachis, glumes, and grain in JM85 were significantly higher than those in JN12, whereas As concentrations in roots and stems did not differ between the cultivars. Grain Cd was significantly higher in JN12 than in JM85, but Cd concentrations in rachis and glumes were similar between the cultivars. The difference in grain Cd concentration between the two cultivars depended on root and stem Cd remobilization and redistribution from rachis to glumes and grain; in contrast, accumulation of As in grain was influenced by As remobilization from the leaves and stem to the spike.
砷（As）和镉（Cd）已知对人体有毒，全球范围内的粮食作物中都有其浓度升高的记录。然而，关于它们在植物发育过程中在小麦植株中的吸收、转运和分布，人们知之甚少。进行了一系列实验，以研究两个小麦品种（JN12 和 JM85；后者是低谷物 Cd 积累品种）在不同发育阶段 As 和 Cd 的空间分布和动态。从分蘖到成熟，根中的 As 浓度降低了 84%，Cd 浓度降低了 67%。相比之下，茎中的 As 浓度增加了 3.1 倍。在成熟阶段观察到根中 As 积累量显著减少，而在伸长阶段根中 Cd 积累量大量减少。所有叶片中的 Cd 浓度和新叶中的 As 浓度随着植物生长而增加。然而，从灌浆到成熟，老叶中的 As 浓度显著降低。在两个品种中，Cd 向幼嫩部位的向上转移大于 As。茎和根中 As 和 Cd 的再移动在两个品种之间存在差异。JM85 中的穗轴、颖片和籽粒中的 As 浓度明显高于 JN12，而根和茎中的 As 浓度在两个品种之间没有差异。JN12 中的籽粒 Cd 明显高于 JM85，但品种间穗轴和颖片中的 Cd 浓度相似。两个品种之间的籽粒 Cd 浓度差异取决于根和茎 Cd 从穗轴向颖片和籽粒的再移动和重新分配；相比之下，As 在籽粒中的积累受叶片和茎中 As 向穗部的再移动的影响。
