NUTRIENT UPTAKE KINETICS OF CLOUDBERRY.

Mineral fertilization of cloudberry (Rubus chamaemorus) has been inconclusive so far. Nutrient absorption of cloudberry was studied by solution depletion 1) to characterize its nutrient uptake kinetics and 2) to determine its preferred nitrogen (N) form. Two accessions, ‘Fjordgull’ (a female cultivar from Norway) and a local wild clonal selection from ‘Baie-Comeau’ (Canada) were tested. Ammonium (NH4) and phosphorus (P) absorption presented a two-component kinetic while nitrate (NO3), potassium (K), and glycine absorption was better fitted with the Michaelis-Menten equation alone. Cloudberry preferences for nitrogen form were in the order: NH4-N, glycine, NO3-N. ‘Fjordgull’ exhibited much higher Kmand Jmaxfor P uptake than the ‘Baie-Comeau’ accession, but they exhibited similar NH4-N uptake kinetics. However, Kmvalues for all nutrients tested except NH4-N were higher than reported for other species. Cloudberry does not appear to have evolved efficient absorption kinetics to compensate for the overall very low abundance of nutrients of peatlands. [ABSTRACT FROM PUBLISHER]