A developmentally stunted mutant (dsm1) of Arabidopsis, isolated from an EMS mutant screen, had a pleiotropic phenotype, including repressed germination, retarded growth, delayed flowering, and impaired fertility. Additionally, dsm1 had a lifespan of approximately 160 days, which was more than twice the lifespan of the wild type (Col-0). Fine morphological and anatomical characters, such as the shoot apical meristem, root apical meristem, seed shape, and seed surface, were obviously altered in dsm1. We found that both abscisic acid and zeatin riboside levels were significantly greater in dsm1 than in Col-0 at all stages of development, while the levels of indole-3-acetic acid and gibberellins varied by age. The expressions of some abscisic acid-related genes were higher in dsm1 than in Col-0. These data indicate that DSM1 may play a general role in plant growth and development.