Phytoserotonin.

Serotonin (5-hydroxytryptamine; SER) is one of the wellstudied
indoleamine neurotransmitters in vertebrates.
Recently SER has also been reported in wide range of plant
species. The precise function of SER at the physiological level,
particularly growth regulation, flowering, xylem sap exudation,
ion permeability and plant morphogenesis in plant system
has not been clear. Though SER is found in different parts of
plant species including leaves, stems, roots, fruits and seeds,
the quantity of SER within plant tissues varies widely. SER has
been recently shown as a plant hormone in view of its auxinlike
activity. This brief review provides an overview of SER
biosynthesis, localization, its role in plant morphogenesis and
possible physiological functions in plants. This would certainly
help to elucidate further the multiple roles of SER in plant
morphogenesis. In the future it may form the basis for studies
on involvement of SER in cellular signaling mechanisms in
plants. Apart from these gaps in understanding the role of SER
in ontogeny of plant physiology and ecological, adaptations
have been emphasized. Thus, overall perspectives in this area
of research and its possible implications have been presented.