Protein composition of sunflower seeds (Helianthus annuus L.) was analysed to identify a possible marker for germination capacity and to evaluate seed viability precociously after harvest and after natural ageing during storage. Electrophoresis on 2-D gels was used to compare total soluble and in vivo synthesized proteins in two seed lots showing different germination capacities. Differences were observed to a greater extent in in vivo protein synthesis profiles than in total soluble proteins. Inhibition of [35S]methionine uptake and incorporation in seeds with low germinability was also observed. The precise relationship between protein composition and prediction of germinability could not be determined. Other aspects such as membrane damage, capacity for protein synthesis and seed lot homogeneity in relation to germination are discussed.
