[Cyclic adenosine-3':5'-monophosphate in translocation tissues of plants?].

Sieve tube sap of the secondary phloem of Robinia pesudoacacia L. and exudate from the trumpet hyphae of the cauloids of Laminaria saccharina (L.) Lamour. were analyzed for the occurrence of cyclic adenosine-3':5'-monophosphate with the help of the radio isotope dilution test (Boehringer, Mannheim). The concentration was about 0,1 μM in the Laminaria exudate and 9,0 nM in the Robinia sap. Pretreatment of the saps with phosphodiesterase removes the activity of the A-3:5-MP. It therefore seems probable that A-3:5-MP occurs in the translocation tissues of plants.