Abstract: The present invention provides a method for increasing the levels of 3?-phosphoadenosine-5?-phosphate (PAP) or a derivative or analogue thereof in cells of said plant compared to an untreated or wild-type plant grown under the same stress conditions. The methods may comprise administration to the plant and/or the soil it is growing in of: PAP or a derivative or analogue thereof, a substance that enhances or promotes synthesis or accumulation of PAP or said derivative or analogue thereof; or a substance that inhibits or compromises an activity metabolising or removing PAP or said derivative or analogue thereof. Alternatively, the methods may comprise genetic modification of cells of said plant which modifications allow for increased accumulation of PAP or a derivative or analogue thereof in cells of said plant (or in seeds thereof) at least under stress conditions compared to a wild-type plant.