关键词: 小麦, 叶面喷锌, 基施氮肥, 锌含量, 蛋白组分

Abstract:

【Objective】 Foliar zinc (Zn) application is an effective agronomic biofortification strategy to realize Zn enrichment of wheat grains and to combat the human Zn malnutrition. The aim of this study was to investigate the effects of spraying Zn with different nitrogen (N) inputs on Zn enrichment and content of protein and protein components in wheat whole grain and flour.【Method】 Based on the long-term positioning experiment, the spraying experiment of Zn in wheat for two consecutive seasons was conducted during 2018-2020. A split plot design was used with soil N rates of 0 (N₀), 120 (N₁₂₀) and 240 ∙hm^-2 (N₂₄₀) as the main plot factor, and the foliar application of distilled water (Zn₀) and 0.4% ZnSO₄·7H₂O (Zn₁) as subplot. The indexes were analyzed for this study, including Zn content of various nutritional organs, Zn mobilization and distribution from leaf and other vegetative organs to grain, and protein and protein component content in grains and flour at the early filling stage and maturation stage. 【Result】Compared with N₀, the grain yield under N₁₂₀ and N₂₄₀ treatments was significantly increased by 88%-114%, but there was no significant difference between N₁₂₀ and N₂₄₀. Regardless of the N inputs, the foliar Zn application could significantly increase the Zn concentration in grains and flour and the grain Zn content reached the biofortification standard. Among those treatments, the Zn concentration of wheat grains under N₁₂₀ and N₂₄₀ was increased by 0.95 and 1.12 times than that under N₀, respectively. Compared with N₀, the N inputs increased the translocation of N and Zn transferred from leaf and other vegetative organs to grain at early grain filling stage, but reduced the transfer ratio of N and Zn: N decreased from 60.2% to 48.6% and Zn decreased from 42.3% to 26.5%. A significant positive linear correlation was found between the amount of N and Zn mobilization and the content of N and Zn in grain at maturity, and the synergistic effect of N and Zn was more significant at Zn₁. Compared with the early filling stage, the content of storage protein (gliadin and glutenin) in grains and flour at the mature stage increased significantly, accounting for about 80%-84% of the protein content. The content of gliadin and glutenin in grain and flour was increased by N application more than that of albumin and globulin, and the gluten was the largest. The content of protein and protein components in grain and flour were not affected by spraying Zn. However, in terms of Zn₁, the increase of gluten content in grain and flour was higher than that under the condition of Zn₀ with the increase of N dosage, which was 37.5% and 38.1%, respectively.【Conclusion】Foliar Zn application could achieve Zn-rich grains but did not affect the content of protein and protein components in grains and flour, indicating that there was sufficient protein pool for Zn storage in grains and flour. Therefore, a reasonable amount of soil N combined with foliar Zn application could increase the N, Zn content and nutritional quality of the grains by ensuring high and stable yield on potentially Zn-deficient calcareous soils.

Key words: wheat, foliar Zn application, basal nitrogen fertilization, Zn content, protein component