Key Laboratory of Plant-Soil Interactions, Ministry of Education, Center for Resources, Environment and Food Security, China Agricultural University , Beijing 100193, China.
J Agric Food Chem. 2014 May 21;62(20):4738-46. doi: 10.1021/jf500273x. Epub 2014 May 13.
Increasing nitrogen supply can increase Fe and Zn concentrations in wheat grain, but the underlying mechanisms remain unclear. Size-exclusion chromatography coupled with inductively coupled plasma mass spectrometry was used to determine Fe and Zn speciation in the soluble extracts of grain pearling fractions of two wheat cultivars grown at two N rates (100 and 350 kg of N ha(-1)). Increasing N supply increased the concentrations of total Fe and Zn and the portions of Fe and Zn unextractable with a Tris-HCl buffer and decreased the concentrations of Tris-HCl-extractable (soluble) Fe and Zn. Within the soluble fraction, Fe and Zn bound to low molecular weight compounds, likely to be Fe-nicotianamine and Fe-deoxymugineic acid or Zn-nicotianamine, were decreased by 5-12% and 4-37%, respectively, by the high N treatment, whereas Fe and Zn bound to soluble high molecular weight or soluble phytate fractions were less affected. The positive effect of N on grain Fe and Zn concentrations was attributed to an increased sink in the grain, probably in the form of water-insoluble proteins.
增加氮供应可以增加小麦籽粒中铁和锌的浓度，但其中的机制尚不清楚。采用排阻色谱-电感耦合等离子体质谱联用的方法，测定了在两种氮水平（100 和 350 kg N ha(-1))下生长的两个小麦品种的麦粒碾磨部分的可溶性提取物中的铁和锌的形态。增加氮供应增加了总铁和总锌的浓度，以及用 Tris-HCl 缓冲液提取不完的铁和锌的部分，并降低了 Tris-HCl 可提取（可溶性）铁和锌的浓度。在可溶性部分中，与低分子量化合物结合的铁和锌，可能是铁-烟碱素和铁-去氧麦根酸或锌-烟碱素，分别减少了 5-12%和 4-37%，而与可溶性高分子量或可溶性植酸部分结合的铁和锌则较少受到影响。氮对籽粒铁和锌浓度的积极影响归因于籽粒中增加了一个汇，可能是以不溶于水的蛋白质的形式存在。
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