Phenotypic analysis of Arabidopsis mutants: flowering time

INTRODUCTIONFlowering in Arabidopsis thaliana is modulated by a number of environmental factors. It is therefore important to perform flowering-time measurements under controlled environmental conditions, including light quality and intensity, day length, temperature, watering, and spacing between plants. Ideally, pots of plants are rotated, and individual plants of different genotypes are placed randomly within the experimental setup. Because of the large influence of environmental effects, it is imperative that only plants grown at the same time and in the same place be compared. Flowering is also modulated by endogenous factors and can thus be affected by mutations in genes that are not primarily involved in the control of flowering time. The variation of flowering time between ecotypes is generally large. Therefore, only those mutants that are induced in the same background can be compared. This protocol describes a method for determining the flowering time of Arabidopsis plants.