The conditions of osmopriming of maize seeds have been established. At an osmotic potential of–1.7 MPa, seed germination is inhibited and seeds osmoprimed for up to 3 weeks show an improved germinability when the osmotic agent is removed. This improvement also applies to seeds that lost vigour because of improper storage conditions. At the biochemical level, embryo axes from osmoprimed seeds can incorporate precursors into DNA, RNA and proteins although at a low level; after removing the osmotic agent, all 3 types of macromolecules are synthesized at much higher levels. No evidence of DNA replication or cell division was found during osmopriming; however, mitotic figures appear several hours earlier in germinated, osmoprimed root tissues compared with the time at which they appear in non-osmoprimed tissues. The behaviour of osmoprimed maize is compared with that of osmoprimed seeds from other plant species.
