In our experiment, two maize inbred lines 478 and Wu312 had smaller shoot dry weight, and the plant density (60,000 plants ha1) was also lower than that in Ple´net and Lemaire’s experiments. As a result, the shoot dry weights of the both inbred lines in our experiments were obvious lower than that in Ple´ net and Lemaire’s experiments at a given time, while the shoot N concentrations were almost the same between the experiments