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 perturbation may be adaptively integrated. In Sorghum bicolor, two developmental windows which enable adaptive adjustment to salinity (increase in tolerance) have been described during vegetative development. A third developmental window is open during the transition between vegetative and reproductive development. This third developmental window was analysed using morphological markers (specific malformations on leaves), 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 adjustment 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 phenomenon is integrated within normal development, but developmental windows are enlarged for plants exposed to perturbation and for their progeny.