cell population phenotype decreased septation index decreased septation 2012-06-08T11:45:02Z A cell population phenotype in which the septation index is lower than normal. The septation index is the proportion of the population undergoing septation at any given time, and is usually around 10% (varying between 7-15%) for wild type. FYPO:0001128 A septation index of zero indicates cell cycle arrest. midori reduced septation index abnormal phenotype