Five members of DELLAs, important plant growth repressors in the gibberellin pathway, have been described in Arabidopsis. DELLAs play an important role in stress tolerance. A low concentration of nitric oxide (NO) can promote plant growth and development, and a high concentration can inhibit plant growth, even cause cell death. We studied the effect of NO at a high concentration in Arabidopsis seedlings by treatment with the NO donor sodium nitroprusside (SNP), and the results indicate that the cell death caused by NO is correlated with H₂O₂ accumulation. Study of phenotypes of serially DELLA-deleted mutants and DELLA gene expression in response to NO revealed that DELLAs contribute greatly to tolerance to NO stress in Arabidopsis seedlings. Thus, we reveal the relationship between DELLA and NO stress in such seedlings, which can contribute to agricultural production.