[en] Flowering in Arabidopsis thaliana is controlled by photoperiod. In long days, the mobile proteins FLOWERING LOCUS T (FT) and TWIN SISTER OF FT (TSF) are produced in the leaves and transported in the phloem toward the shoot apical meristem (SAM). In the SAM, FT and TSF interact with the transcription factor FD to activate the expression of genes responsible for floral meristem identity [1]. Since the formation of flowers and fruits is a costly and critical stage for the plant, it is expected to be supported by a well developed root system to insure the increase in plant’s needs. As a first step to understand the effects of flowering on root growth, we compared root development in long days, promoting flowering, and in short days (16h and 8h days, respectively).