What is the site of perception of photoperiod necessary for induction of flowering in plants?

The site of perception of light/dark duration are the leaves. It has been hypothesized that there is a hormonal substance that is responsible for flowering. This hormonal substance migrates from leaves to shoot apices for inducing flowering only when the plants are exposed to the necessary inductive photoperiod.Lateral buds is a meristematic tissue hence not site for photoperiodism. The meristematic tissues generally perceive the stimulus for vernalization.Pulvinus is the swollen part of the petiole of the leaf.Shoot apex contains meristematic tissues hence not site for photoperiodism.