| Zinc and iron are essential micronutrients for plant, animal and human beings, it is not only essential for plant growth, but also associated with the health of people and animal through food chain. Zinc and iron deficiency in soils influence not only yield of the crops and livestock products, but also the nutritional quality. Zinc and iron concentrations of wheat grain are directly related to the health of people whose diets are mainly composed by cereal-based foods. Wheat is mainly grown in calcareous soil in north China, where the content of availability zinc and iron in soils is very limited, so planting wheat with high efficiency on uptake and utilization of zinc and iron has been regarded as a good way. A pot and a field experiment were carried out in this study to evaluate the ability of uptake to zinc or zinc and iron, and also to exploit the potential capacity of taking up and utilization of zinc and iron from soil by plant itself, it is expected to provide some useful information for screening wheat genotypes of high Zn and Fe efficiency, and enhance the nutritional quality of wheat. The main results obtained were as follow:(1) The 20 types of different wheat genotypes were used in pot experiment to investigate the responses to zinc fertilization; the levels of zinc treatment included no zinc fertilization and zinc fertilization (20 mg Zn/kg), the experiment totally lasted 68 days in a greenhouse. The results showed that, the effect of zinc fertilization on yield of different wheat genotypes was not significant under the condition of available Zn was 0.6 mg/kg in the calcareous soil tested, and root to shoot ratios also were almost not affected by zinc fertilization, and they mainly depend on genotypes of wheat. However, the Zn concentration and uptake in different parts of the wheat plants substantially increased compared zinc fertilization to without fertilization. The Zn concentration in root, stem, leaf and grain of wheat plants were increased about 0.22-3.22, 0.26-2.82, 0.10-3.84 and 0.10～0.84 folds, respectively. The Zn uptake in whole plants increased by about 28.8～219.3%, and the average value was 104.8%. There existed big difference in translocation rate to zinc among different wheat genotypes, the range was 13.5%～90.2%. the translocation rate of the six genotypes which had grain was much higher than the remain genotypes which had no grain, it indicated that the filling stage was a crucial stage for Zn to be translocated from root to spike. Zinc fertilization also increased the available Zn content in soil. In general, zinc fertilization is an important and effective measure to improve nutritional status of wheat.(2) For field experiment, split-split design was used in field arrangement, the main factor was genotypes, sub-factor was nitrogen fertilization, sub-sub-factor was zinc and iron fertilization; 105 kg N/hm~2 and no nitrogen fertilization was used as two levels of nitrogen treatment; the zinc and iron fertilization was used on the levels of 6.8 kg Zn/hm~2, 12.1 kg Fe/hm~2 and no zinc and iron fertilization; 10 types of wheat genotypes was used this experiment. The result of testing at reviving stage showed that, nitrogen fertilization significantly influenced on seedling yield, number of tillers and chlorophyll SPAD value of 10 types of wheat genotypes, and they were increased by 15.8%, 14.7%, 4.6%, respectively. Application of zinc and iron fertilizers also significantly influenced on seedling yield, number of tillers, but almost did not impose on chlorophyll SPAD value; the seedling yield increased by 8.0%, but the number of tillers decreased 5.8%; the growth status of different genotypes of wheat showed large variation. The nitrogen fertilization could greatly increase zinc concentration and uptake to all of wheat genotypes tested, and they increased by 7.6%, 22.9% averagely, respectively, but the iron concentration decreased 6.4% and the iron uptake increased by 7.2%; Application of Zn, Fe fertilizers increased significantly zinc concentration and uptake by 11.9%, 19.2%, respectively, but there was no obvious influences on iron concentration and uptake. There existed some differences for concentration and uptake of zinc and iron among varied wheat genotypes, the largest three genotypes for uptake amount of zinc and iron were Mianyang 31, Shanyou 225 and Shanyou 253.(3) In the field experiment, samples were collected and analyzed at various growth stages (jointing stage, flowering stage, early grain-filling stage, later grain filling stage and maturity stage) behind reviving stage of wheat. The results showed that, the zinc concentrations and uptake of each organ of wheat plants were increased after using nitrogen fertilization, also did iron concentration and uptake; the ranges of zinc and iron concentration were 1.66%-36.70% and 0.05%-15.57%, respectively; the ranges of zinc and iron uptake were 3.15%-57.71% and 1.52%-30.12%, respectively; After using nitrogen fertilization, the concentration of nitrogen, zinc and iron were increased by 7.90%, 7.24% and 1.68%, the uptake of nitrogen, zinc and iron were increased by 9.39%, 10.14% and 4.43%, but the yield was only increased by 2.17%; this showed that using nitrogen appropriately could increase the uptake of zinc and iron of wheat significantly. After using zinc and iron fertilization, the concentration of zinc and iron in each organ of wheat had no large difference compared to no zinc and iron fertilization, but the uptake of zinc and iron was increased by varied extent, the range were 0.14%-16.65% and 0.15%-16.68%, respectively; The uptake of nitrogen, zinc and iron of wheat grain were increased by 4.14%, 4.82% and 6.82%, respectively to zinc and iron fertilization, and the yield of grain also increased by 3.94%.(4) To the 10 genotypes which used in the field experiment, the zinc and iron concentration of stem and leaf were highest at jointing stage, and decreased largely at each growth stage that after jointing stage; zinc and iron concentration of shell reached their highest values at flowering stage and early grain filling stage, respectively; the zinc and iron concentration of grain increased gradually at the grain filling stage.(5) There is evident genotypic difference on grain yield of various wheat genotypes, the range was 5618.4 kg/hm~2-7528.2 kg/hm~2, and the highest was Shanyou 225, the lowest was Wunong 148; the dry weight of different wheat organs were increased by nitrogen fertilization, also did zinc and iron fertilization; the range were 2.17%-11.24% and 3.94%-12.73%; the obvious genotypic difference on uptake of nitrogen, zinc and iron of grain also existed, the range were 128.07 kg/hm~2-148.43 kg/hm~2, 235.07 g/hm~2-296.10 g/hm~2 and 456.27 g/hm~2-593.83 g/hm~2; the nitrogen, zinc and iron uptake of grain were increased by 9.39%, 10.14% and 4.43% to nitrogen fertilization; but to zinc and iron fertilization, the range were 4.14%, 4.82% and 6.82%; in general, among the 10 genotypes tested, Xinmai13, Xiaoyan6 and Shanyou253 had the largest uptake amount for nitrogen, zinc and iron in grain.
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