Differential Specificity Exhibited by Two Germination Inhibitors Present in Echium Plantogineum L.

Abstract

The widespread occurrence of seed-germination inhibitors which come from sources external to seeds, and which apparently control germination by inhibiting embryo growth (mainly the radicle) once it has started (Moewus and Schader 1951; Mayer and Evenari 1952) is well appreciated. Examples of this class of inhibitor have been detected both in the juices or extracts of fruits or other structures derived from parts of flowers (Evenari 1949; Moewus, Moewus, and Schader 1951), and in vegetative structures (Konis 1947; Winter and Sievers 1952; Yardeni and Evenari 1952; Bublitz 1953; Winter and Bublitz 1953). It is also recognized that they are largely non-specific, in that a given inhibitor may react differently against different seeds, as well as a given seed showing different sensitivity to different inhibitors (Evenari 1949; Koller 1955; Toole et al. 1956). It does not appear to have been explicitly stated that both these aspects of non-specificity may be observed in a single source. Evidence to this effect is presented in this communication.