PERTURBATION IN LEAVES OF SALT-TREATED SORGHUM - ELEMENTS FOR INTERPRETATION OF THE NORMAL DEVELOPMENT AS AN ADAPTIVE RESPONSE

Developmental windows are specific periods of sensitivity in which a p erturbation may be adaptively integrated. In Sorghum bicolor, two deve lopmental windows which enable adaptive adjustment to salinity (increa se in tolerance) have been described during vegetative development. A third developmental window is open during the transition between veget ative and reproductive development, This third developmental window wa s analysed using morphological markers (specific malformations on leav es), and their relationship with vegetative and reproductive events. A positive link was observed between fertility and malformations on the last leaf. We concluded that this late window enables an adaptive adj ustment of reproductive development, counteracting the negative effect of salt adaptation on fertility. Developmental windows open following rapid changes in growth of the different organs, They permit adaptive adjustments to emergence or senescence of various organs. This phenom enon is integrated within normal development, but developmental window s are enlarged for plants exposed to perturbation and for their progen y.