Leaf malformation during early development in Sorghum. Evidence for an embryonic developmental window

Salt adaptation was induced in two successive generations of Sorghum bicolor, and the germination of their seeds was compared. When germinated in the absence of NaCl, the progeny of adapted plants displayed a specific malformation at the first two leaves, which was never observed in progeny of control plants. The frequency of leaf malformation was enhanced in progeny of the second generation of adapted plants, indicating a cumulative influence of salt adaptation. When germinated in the presence of 75 mM NaCl, seedlings from seeds of salt-adapted plants never displayed the leaf malformation, whereas it was observed on seedlings from seeds of control plants germinated in the presence of 75 mM NaCl. The occurrence of leaf malformation was analyzed for progeny of 20 salt-adapted plants germinated in the absence of NaCl. The link with the reproductive characters of the parents indicates a strong parental control on the expression of the leaf malformation. A comparison with previous data relative to the leaf malformation in Sorghum suggests the existence of a developmental window which 'opens' during embryo morphogenesis. This enables the imprinting of the embryo by the parent's physiological environment. This conclusion is related to other data describing a long-term maternal influence in plants.