XVI International Botanical Congess

Treatment of seeds with very high doses of gamma radiation results in the production of gamma plantlets. These miniature plants germinate at normal rates and exhibit normal responses to changes in their environment but cease their growth at an early stage. The arrest occurs at a stage corresponding to the presence of the plant organs at the time of irradiation, i.e., Arabidopsis gamma plantlets produce cotyledons, but not true leaves, as the mature embryo has cotyledons, but not leaves. It is possible that this phenomenon reflects the arrest of cell division in response to DNA damage. In an effort to identify genes involved in this putative signal transduction pathway, our laboratory has initiated a search for mutants that lack the gamma plantlet response. We will discuss the interesting phenotype of these sog (suppressor of gamma) mutants.