Seed-sprouting in tomato fruits

Abstract Although tomato juice possesses properties which are inhibitory to seed germination, sprouting of seeds has been observed frequently in ripe tomatoes of mechanical harvest cultivars ‘VF 145’ and ‘VF 13L’. Juice from these cultivars was less inhibitory to tomato seed germination, as determined by bioassays, than that of other cultivars. There was no difference in the inhibition between juice from the pulp and that from the locular gel. Soluble solids accounted for 44% of the inhibition, osmotic concentration 2%, and pH only 0.2%; and the remainder came from other constituents in the juice. Abscisic acid and 2 unidentified substances in the juice isolated by extraction and chromatography were shown to inhibit seed germination; the degree varied with maturity and cultivar. Injection of abscisic acid into the vascular tissue of the stem scar inhibited sprouting within the fruit. Gibberellic acid and kinetin gave variable results, depending upon harvest dates. Fruits from plants grown in low potassium nutrient culture solutions had increased sprouting of seeds. Presented at the XXth International Horticultural Congress, Sydney, Australia, August 1978, Abstract 1189