During flowering four different types of floral organs need to be formed: sepals, which protect the inner organs; the frequently ornamental petals; stamens, which produce pollen and the carpels. This process is orchestrated by a large number of genes. Scientists at the Max Planck Institute for Plant Breeding Research in Köln (Germany) found, in cooperation with colleagues in Nijmegen (Netherlands) that a small molecule, a so-called microRNA, is crucial for the control of floral organs identity

The length of the day relative to night, or photoperiod, is a strong determining factor for the induction of flowering in many plant species. Short day (SD) plants require a short day length (or more precisely, a long night) in order to flower. These are plants that flower as the days grow shorter, such as in the fall in temperate regions.