METABOLISM OF ISOPENTENYLADENOSINE IN THE ROOTS OF NORWAY SPRUCE SEEDLINGS EXPOSED TO NUTRITIVE STRESS

Seedlings of Norway spruce (Picea abies) were grown on a low nutrient medium containing Al3+ ions (0.8 mM, stress) and a rich medium that wa s suitable for spruce and lacked Al3+ (control). After feeding with tr itiated isopentenyladenosine via the roots, the metabolism of cytokini ns in the roots of stressed and control plants was compared. HPLC radi oactivity profiles of root extracts showed that isopentenyladenosine w as mainly degraded to isopentenyladenine- and adenine/adenosine-like c ompounds. Stressed and non-stressed seedlings clearly differed with re spect to the distribution of radioactivity for the different metabolit es. The measurements showed that the degradation of isopentenyladenosi ne was strongly reduced in the roots of the stressed seedlings. Result s are discussed with regard to the levels of endogenous cytokinins mea sured in spruce affected by the novel type of forest decline.