Desiccation induces an increase of reactive oxygen species (ROS) in chloroplasts, mitochondria and peroxisomes as cellular water content decreases. Cruz de Carvalho et al. examine how dehydration rate influences ROS production and cell damage in the aquatic bryophyte, Fontinalis antipyretica, through the use of confocal laser microscopy and a ROS-specific chemical probe. They find that rehydration of cells that have been dried slowly is associated with lower ROS production than in cells dried at a faster rate, thereby reducing the amount of cellular damage and increasing cell survival. They thus conclude that a slow dehydration rate may induce cell protection mechanisms that serve to limit ROS production upon subsequent rehydration.