Abstract:In order to investigate effects of nitrogen form on root morphology, nitrogen accumulation in shoots of rice, and nitrogen absorption by roots, two rice cultivars, Guidan-4, high in nitrogen efficiency at the seedling stage, and Nanguang, low in nitrogen efficiency, were used in the experiment, which had three N treatments, 1.0 mmol/L NO3--N, 0.5 mmol/L NH4NO3, and 1.0 mmol/L NH4+-N. Results showed that Treatment NO3--N was obviously higher than Treatment NH4+-N in root tips, root surface area and root length though difference did exist between the two cultivars. Both of the two cultivars took up the highest amount of nitrogen in Treatment 0.5 mmol/L NH4NO3, and then in Treatment 1.0 mmol/L NH4+-N and Treatment 1.0 mmol/L NO3--N.