Non-juvenile plants are very responsive to photoperiodic stimulus and flower about two weeks after induction. The critical photoperiod seems to be about 13.5 hours, but there are likely to be photoperiod x temperature interactions. The plant is unadapted to the tropics because flowering will be induced when the plants are very small. Nonvolatile sesquiterpenes can be recovered from the plant by solvent extraction, some of which show high antimalarial activity. In vitro Production A. annua is easily propagated in vitro by standard protocols.
Cytokinins increase shoot proliferation but decrease rooting and increase vitrification.
A. annua can be grown and propagated by microcuttings in a hormone-free medium. Artemisinin is produced in shoots in vitro and is enhanced by the presence of roots. None or trace levels of artemisinin are found in roots, callus, cells, or cell free medium. There is no evidence that in vitro production of artemisinin will be commercially feasible. Field Production Field production of A. annua is presently the only commercially viable method to produce artemisinin because the synthesis of the complex molecule is uneconomic.