在4个硝酸盐浓度下进行2个玉米品种盆栽砂培试验,研究玉米根系特征的基因型差异对硝酸盐浓度的响应及与氮素吸收效率的关系。结果表明,氮高效品种郑单958在硝酸盐浓度为0.08、0.8、4.0 mmol/L时,根重、根幅、根长、根表面积、根体积、分枝数、分形维数、根系活力均显著高于氮低效玉米品种内单314。各根系形态指标随硝酸盐浓度的增加逐渐增加,当硝酸盐浓度从4.0 mmol/L增加至8.0 mmol/L时,不同基因型品种间差异不显著。在低氮胁迫条件下,玉米主要通过增加细根比例、增加根表面积吸收更多的氮素;在氮素供应充足条件下,通过增加根系平均直径,形成高密的分枝系统吸收氮素。进一步通径分析表明,根长与根体积对氮吸收效率直接影响最大,是氮吸收效率差异的主要原因。 Pot experiments were carried out on pots of two maize cultivars at four nitrate concentrations to study the response of genotypic differences in root characteristics of maize to nitrate concentration and its relationship with nitrogen absorption efficiency. The results showed that the root vigor, root length, root length, root surface area, root volume, number of branches, fractal dimension, root activity of nitrogen-efficient variety Zhengdan 958 were significantly higher than those of the other two varieties at the nitrate concentration of 0.08,0.8,4.0 mmol / Significantly higher than nitrogen inefficient maize varieties within a single 314. The morphological indexes of the roots increased with the increase of nitrate concentration. When the nitrate concentration was increased from 4.0 mmol / L to 8.0 mmol / L, there was no significant difference among different genotypes. Under the condition of low nitrogen stress, corn mainly increased the root surface area and absorbed more nitrogen by increasing the proportion of fine roots. By increasing the average diameter of the root system, a high-density branching system was formed to absorb nitrogen under sufficient nitrogen supply. Further path analysis showed that root length and root volume had the greatest direct impact on nitrogen absorption efficiency, which was the main reason for the difference in nitrogen absorption efficiency.