BIOCHEMICAL AND CYTOLOGICAL STUDIES ON OSMOPRIMED MAIZE SEEDS

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