| Zinc（Zn） deficiency is a widespread problem in the world, especially in the developing regions where staple foods derived from cereals are the main source of daily micronutrients intake. Therefore, the increase of Zn content in the endosperm, which is consumed as wheat flour by human being, is the main challenge in the research area of biofortification. Winter wheat cultivar Yangmai 16 and Yangfumai 2, grown in a cement tank filled with clay loam soil, were treated by foliar Zn application at 3 rates of 0（control）, 0.2% and 0.4% ZnSO4 at grain filling stage. The first Zn treatment was applied at 1 week after flowering（WAF）, the second and third application were at 2 WAF and 3 WAF, respectively. The plants in control plots received clean water. The results showed that foliar Zn application of 0.2% and 0.4% ZnSO4 increased grain Zn concentration by 58% and 125%, respectively. Wheat grains were further separated by Sedimat Laboratory Mill into bran, shorts and flour, and Zn concentration in each grain fraction were analyzed by ICP-AES. Zn concentration in different milling fractions followed the order of bran > shorts > flour, and Zn concentration in bran was 8 times higher than in flour. Compared with control, foliar 0.2% ZnSO4 application increased Zn concentration in bran, shorts and flour by 64%, 54% and 36%, respectively; and 0.4% ZnSO4 treatments increased Zn concentration in bran, shorts and flour by 117%, 110% and 92%, respectively; As the case of Zn concentration in grain fractions, Zn contents in bran, shorts and flour showed same trend in the response to foliar Zn application at grain filling stage. However, foliar Zn application at grain filling stage did not affect Zn distribution in different milling fractions of mature grains. Compared within cultivars, foliar Zn application had greater effect on Yangmai 16 than Yangfumai 2, as showed by most measured parameters. These results indicate that suitable cultivar selection accompanied with foliar Zn applications at grain filling stage improve Zn level of wheat flour, which will have beneficial effect on human health. |
