Dopamine biosynthesis at different stages of plant development in Papaver somniferum.

Latex and cell-free extracts of various organs and stages of plant and capsule development in Papaver somniferum, the opium poppy, synthesized dopamine, an alkaloid precursor, from 14C-dopa. The 1000 g X 30 min supernatant from latex of the pedicel-capsule junction converted more dopa than latex supernatant from the upper capsule or lower pedicel regions, although there was more protein in the latex from the capsule. Percent conversion of pedicel-capsule latex into dopamine was maximum in unopened flower buds and decreased within 14 days after flowering. Dopamine biosynthesis in latex and cell-free extracts also varied with the stage of organ development. Extracts from capsule tissue converted more labeled dopa into dopamine than did extracts from pedicels, leaves from vegetative plants at the rosette stage, leaves from flowering plants, or pedicels connected to capsules.