Response of nitrogen metabolism to nitrogen regulation in different nitrogen-efficient rice seedlings

Abstract The aim of this study was to determine the different mechanisms of nitrogen absorption and nitrogen regulation response of different rice varieties with diverse nitrogen efficiencies.On the premise of the same root distribution angle and the same type of DRO1 gene, the DRO1 gene of the low-nitrogen-efficient rice variety was highly expressed under low-nitrogen conditions, which made the root length and the depth of rooting significantly increased compared to that of the high-nitrogen-efficient rice variety. The high expression of key enzyme genes of nitrogen absorption and assimilation (OsAMT2;1, OsGS2, OsGS1;1, OsGS1;2) under low-nitrogen conditions in the low-nitrogen-efficient rice variety had higher nitrogen and phosphorus absorption capacity, and thus improved the accumulation of dry matter in plants. The expression of nitrogen metabolism genes at the seedling stage of different nitrogen-efficient rice varieties showed significant differences in the corresponding laws of nitrogen regulation. The high expression of nitrogen metabolism genes in the high-nitrogen-efficient rice varieties under the condition of sufficient nitrogen fertilizer ensured the full absorption and assimilation of nitrogen.The limiting factors of nitrogen absorption in the seedling stage of the two nitrogen-efficient rice varieties differed under the control of nitrogen fertilizer. The main reason for low nitrogen and high efficiency was that low-nitrogen-efficient rice varieties had a strong rooting ability under low-nitrogen conditions.