Desiccation of oat grains during and following germination, and its effects upon protein synthesis

Abstract

After imbibition and germination, oat grains pass from a stage where they are insensitive to desiccation to a stage where they are sensitive. Desiccation of germinating grains results in more rapid completion of germination upon rehydration. However, when the initial imbibition (i.e. predesiccation) time of the grains is taken into account, the total time that the seeds are hydrated before germination is completed is the same as control (once-imbibed) grains. Hence it appears that events occurring prior to desiccation do not have to be repeated for germination to be completed. Grains desiccated during germination commence protein synthesis more quickly, and reform polysomes more quickly, than control (once-imbibed) grains. Likewise, RNA synthesis resumes more quickly. Desiccation of grains during the desiccation-sensitive stage results in almost total impairment of protein and RNA synthesis upon subsequent rehydration. Both ribosomes and poly(A)+-containing RNA are conserved in embryos desiccated during the insensitive stage, but poly(A)+-containing RNA is lost from embryos desiccated during the sensitive stage and there is a further decline upon subsequent rehydration.