Transgenerational stress memory transferred from parents to offspring may enable plants to respond to changing environments rapidly. Yet transgenerational adaptive effects and underlying mechanisms in response to waterlogging and drought are still unclear. Furthermore, transgenerational cross-stress tolerance, pre-adapting offspring to any stress when maternal plants experienced stress, is currently understudied. We conducted a full-factorial pot experiment over two generations, using four perennial plant species and subjecting maternal and offspring plants to waterlogging and drought. We hypothesized that offspring experiencing stress performed better when mothers had experienced stress before, irrespective of the type of stress. We found increased biomass and reproductive output in offspring experiencing the same stress conditions as their mothers (transgenerational adaptive effects). However, a maternal stress experience per se did not pre-condition offspring to other types of stress. Transgenerational adaptive effects were linked to changes in the antioxidative system of one species, reducing oxidative damage through upregulation of protective enzymes in offspring experiencing the same conditions as their mothers. Our research provides evidence for transgenerational waterlogging and drought memory and links this to underlying photosynthetic and redox-related mechanisms. Transgenerational adaptive effects acting on the antioxidative system might therefore contribute to the rapid responses of plants to environmental change.
