[Abscisic acid and inhibition of seed germination in the fruit of Solanum lycopersicum L].

The germination inhibiting effect of the juice from ripe tomato fruit tissue surrounding the seeds was analysed. The most important factor seem to be osmotic substances contained in the sap. Isotonic solutions of sucrose, glucose and Na2SO4 inhibit germination of tomato seeds completely. The osmotic inhibition is increased by a ether soluble acid germination inhibitor ("Blastokolin" according to Köckemann, 1934), which was identified as abscisic acid (ABA). ABA alone cannot be responsible for the inhibition of germination, since concentrations of synthetic racemic ABA corresponding to the natural concentration of ABA in the fruit flesh have only a slight inhibitory effect in vitro. Moreover, volatile germination inhibitors are present, but their exact importance and chemical nature was not analysed. The results are discussed in the light of earlier papers concerning the problem of germination inhibition in fruits.