Increased Abscisic Acid Biosynthesis during Plant Dehydration Requires Transcription.

Excised pea plants were rapidly dehydrated to turgor pressures of 1.5 to 2.0 bars. After a 30 minute lag, abscisic acid (ABA) levels increased approximately 100-fold in the dehydrated plants. Pretreatment of plants with the transcription inhibitors actinomycin D or cordycepin or with an inhibitor of cytoplasmic protein synthesis prior to plant dehydration inhibited the synthesis of ABA. These results suggest that dehydration induced synthesis of ABA requires nuclear gene transcription.