Effects of controlled deterioration and osmopriming on protein synthesis of cauliflower seeds during early germination

Profiles of proteins synthesized in vivo in radicle tips were compared among unaged, artificially aged (controlled deterioration: 10% moisture content at 42 degrees C for 3 weeks), osmoprimed (-1.5 MPa polyethylene glycol 6000 at 20 degrees C for 1 week), and artificially aged and subsequently osmoprimed cauliflower (Brassica oleracea L.) seeds. Germination and initiation of incorporation of S-35-methionine into radicle tips were delayed by controlled deterioration. Osmopriming accelerated these processes and also alleviated the delays. The labelled proteins were analysed by two-dimensional gel electrophoresis and fluorography. Proteins were found whose expression correlated with the rate of germination, and was reduced by controlled deterioration but enhanced by osmopriming. Subsequent osmopriming reversed the effect of controlled deterioration and even caused an enhancement up to the level of unaged osmoprimed seeds. These proteins appeared to be related to processes preceding visible germination. In unaged seeds, formation of the proteins in the radicle tip began upon imbibition but decreased towards visible germination. On silver-stained gels, one of the proteins was shown to be mobilized by the time of radicle protrusion, while all were found in dry seeds. Proteins whose pronounced expression was observed only after both treatments were also found.