Welch Ross M, House William A, Ortiz-Monasterio Ivan, Cheng Z
U.S. Plant, Soil and Nutrition Laboratory, Agricultural Research Service, U.S. Department of Agriculture, Cornell University, Ithaca, New York 14853, USA.
J Agric Food Chem. 2005 Mar 23;53(6):2176-80. doi: 10.1021/jf040238x.
A "whole-body" radioassay procedure was used to assess retention and absorption by rats of Zn in mature kernels of whole grain wheat harvested from 28 genotypes (Triticum spp.) grown in nutrient solution supplied with 2 microM ZnSO4 radiolabeled with 65Zn. Grain-Zn concentration differed among genotypes and ranged from 33 to 149 microg g(-1) of dry weight (DW); similarly, grain-Fe concentration varied approximately 4-fold, from 80 to 368 microg g(-1) of DW. Concentrations of Zn and Fe in the grain were positively correlated. Therefore, selecting genotypes high in grain-Zn also tends to increase grain-Fe concentration. Concentrations of myo-inositolhexaphosphate (phytate) in the wheat grain varied from 8.6 to 26.1 micromol g(-1) of DW. Grain intrinsically labeled with 65Zn was incorporated into test meals fed to Zn-depleted rats. All rats readily ate the test meals, so that Zn intake varied directly with grain-Zn concentration. As determined by the percentage of 65Zn absorbed from the test meal, the bioavailability to rats of Zn in the wheat genotypes ranged from about 60 to 82%. The amount of bioavailable Zn (micrograms) in the grain was positively correlated to the amount of Zn accumulated in the grain. There was a significant negative correlation between grain-phytate levels and percentage of Zn absorbed from the wheat grain, but the effect was not large. These results demonstrate that concentrations of Zn in whole-wheat grain, as well as amounts of bioavailable Zn in the grain, can be increased significantly by using traditional plant-breeding programs to select genotypes with high grain-Zn levels. Increasing the amount of Zn in wheat grain through plant-breeding contrivances may contribute significantly to improving the Zn status of individuals dependent on whole grain wheat as a staple food.
采用“全身”放射性测定法，评估从28种基因型（小麦属）的全谷物小麦成熟籽粒中锌的保留和吸收情况，这些小麦种植在添加了用65Zn放射性标记的2 microM硫酸锌的营养液中。基因型间籽粒锌浓度不同，干重范围为33至149微克/克；同样，籽粒铁浓度约有4倍差异，干重范围为80至368微克/克。籽粒中锌和铁的浓度呈正相关。因此，选择籽粒锌含量高的基因型也往往会提高籽粒铁浓度。小麦籽粒中肌醇六磷酸（植酸盐）的浓度在8.6至26.1微摩尔/克干重之间变化。用65Zn进行内在标记的籽粒被掺入喂给缺锌大鼠的试验餐中。所有大鼠都乐意食用试验餐，因此锌摄入量与籽粒锌浓度直接相关。根据从试验餐中吸收的65Zn百分比测定，小麦基因型中锌对大鼠的生物利用率在约60%至82%之间。籽粒中可生物利用锌的量（微克）与籽粒中积累的锌量呈正相关。籽粒植酸盐水平与从小麦籽粒中吸收的锌百分比之间存在显著负相关，但影响不大。这些结果表明，通过传统植物育种计划选择籽粒锌含量高的基因型，可以显著提高全麦籽粒中的锌浓度以及籽粒中可生物利用锌的量。通过植物育种手段增加小麦籽粒中的锌含量，可能对改善以全麦为主食的个体的锌营养状况有显著贡献。
