Nitrogen as a key nutrient among populations of Phalaris arundinacea

Abstract

Currently bigger attention started to be paid to the quality of inland waters, which receive substantial nutrient inputs such as nitrogen (N). Although data regarding riparian species response to pollution by nutrients are very poor in Lithuania. Among water macrophytes of our country, reed canary grass (Phalaris arundinacea L.) is a common and frequently occurring species. Due to huge biomass much attention is paid to this plant for its use as biofuel, for bioremediation, for forage or ornamental purposes. We investigated leaf N concentration differences and compared it among populations of P. arundinacea growing in different sites of Lithuanian rivers. Our study involved over 60 populations, sampled on Nemunas, Venta, Lielupė and coastal river catchments of Lithuania. Nitrogen concentrations were determined using Kjeldahl method and expressed as percentage of dry mass (d. m.) of the leaf tissue. Mean leaf N concentration for all populations of P. arundinacea was 3.50 % d. m. The lowest N concentration (3.03 % d. m.) was documented in population sampled on the bank of the river Merkys, while the highest (3.69 % d. m.) was observed in population near the Neris river, the most contrasting ones differed by 1.32 times (p < 0.05). Leaf N concentrations of P. arundinacea were compared to the same parameter of some other riparian plant species: in respect to N concentrations, P. arundinacea was of intermediate position: higher than Lythrum salicaria or Stuckenia pectinata, although lower compared to Bidens frondosa. Phragmites australis, Nuphar lutea or Echinocystis lobata.[...]