Flower initiation is an important morphogenetic event. In this brief review the formative, ultrastructural, cytological and biochemical changes that occur in the transitional meristems in a few selected species have been discussed. In the evoked meristems, the number of plastids, mitochondria and ribosomes are usually higher. Further, an early shift of 4C nuclei to the 2C value, an increase in respiration and enhanced activities of dehydrogenase and phosphatase have been observed. The molecular events that ensue immediately after induction need further study.
The factors that regulate flower morphogenesis in vitro and reversal of excised flower buds to vegetative growth have been discussed. Reports on the modification of inflorescence development through the application of growth regulators have been analysed.