Cytokinin-induced Pseudonodules on Alnus glutinosa

Alder root nodules are capable of atmospheric nitrogen fixation. A differential treatment with kinetin and 2IP (2-isopentenyl adenine) was applied to the rooting medium of alder plants growing in test tubes containing Crone solution. The experiment led to the formation of a fair number of pseudonodules scattered on the root system of the plants treated with cytokinin levels higher than 0.6 μg/ml. Kinetin had a lowering effect on the overall growth of the plant, whereas the plants treated with 2IP showed no differences in growth as compared to the non-treated control plants. Histological sections of the pseudonodules show an unorganized tissue originating from the parental root cortex, and the presence of groups of tracheids giving the aspect of unorganized vascular bundles.