Nitrogen partitioning in maize organs and underlined mechanisms from different plant density levels and N application rate in China

文献类型： 外文期刊

第一作者： Duan, Fengying

作者： Duan, Fengying;Wei, Ze;Soualiou, Soualihou;Zhou, Wenbin

作者机构：

关键词： Maize; Planting density; Yield; NUE; Nitrogen allocation; Nitrogen translocation

期刊名称：FIELD CROPS RESEARCH （ 影响因子：5.8； 五年影响因子：6.9 ）

ISSN： 0378-4290

年卷期： 2023 年 294 卷

页码：

收录情况： SCI

摘要： Context: Optimal plant density and nitrogen (N) application rate are important to achieve high maize yield. High plant density increases plant-plant competition for light and nutrients. However, too much applied N promotes excessive vegetative growth and delays maturity, resulting in low N use efficiency (NUE) and potentially envi-ronmental problems. The physiological and molecular mechanisms behind the interaction between plant density and N application rate are largely unknown.Objective or hypothesis: We hypothesized that simultaneously improving maize yield and NUE depends on fine regulation of nitrogen partitioning in response to the interaction between nitrogen applications and plant densities.Methods: With a 2-year field experiment, we performed phenotypic, physiological, and gene expression analyses under two plant densities (low density of 60,000 plants ha-1 and high density of 90,000 plants ha-1) and three nitrogen application levels [115 (N1), 190 (N3) and 430 (N4) kg N ha-1l in the high N-responsiveness maize cultivar ZD958.Results: By labeling maize with 15N, 2-year results showed that both 15N uptake per plant and 15N partitioning to ear decreased under high-density conditions. Compared to N1 treatment, application of N to N3/N4 level increased maize yield by 13.9%-43.2%, which can be explained by bigger root angle, larger leaf area and lower lodging rate under high density condition. In addition, results in 2019 experiment showed that yield, NUE, ni-trogen allocation to stem and the expression of some N transporter genes were regulated by the interaction between nitrogen applications and plant densities. Compared to the N4 treatment, N3 treatment has a 55.8% reduction in N, a tendency of increase in population yield, and increased NUE by 59.6% and 63.0% in low -density and high-density plantings, respectively. Our proposed model suggested that the appropriate N supply increased NUE by either increasing N translocation from leaves to ears under low-density conditions or by increasing N allocation to ears rather than to stems under high-density conditions.Conclusions and significance: Based on correlation analysis, N allocation/translocation and expression of nitrogen transporter genes could be used as biomarkers to indicate appropriate levels of N application under different planting densities, and are thereby important for the simultaneously improving ZD958 yield and NUE in intensive agriculture.

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