At what point does meiosis occur during the development of a flower?
In case of male gametophyte (in angiosperms), meiosis ends before the formation of the pollen tetrads which in turn marks the end of cell division in anthers and petals (Li and Johnston, 1999). However, the same study reveals that the relative timing of pollen tetrad formation with respect to floral development (abbreviated as RAFT), varies between different plants. Despite the variation, they seem to form three clusters with mean RAFT at 0.45, 0.62 and 0.73.
In case of the female gametophyte, the megasporogenesis happens inside the ovule (Yadegari and Drews, 2004). Therefore, ovule should have formed before the onset of meiosis. I could not find a detailed study on the timing of the megasporogenesis.