title: Nitrate reductase activity in some subarctic species and UV influence in the foliage of Betula pendula Roth. seedlings.
abstract: Nitrate reductase (NR) activity was studied in the foliage of five subarctic species: mature trees of European white birch (Betula pubescens Erch. S.S.), Scots pine (Pinus sylvestris L.), Norway spruce (Picea abies L. Karst), Ericaceous shrub bilberry (Vaccinium myrtillus L.), naturally growing in a forest, and seed-grown silver birch (Betula pendula Roth.) seedlings in an ultraviolet (UV) exclusion field experiment at the Pallas-Ounastunturi National Park in Finnish Lapland (68 degrees N). Mean NR activity ranged from 0 in bilberry to 1477 (S.D. = 277.7) and 1910 (S.D. = 785.4) nmol g(-1) DW h(-1) in mature trees of European white birch and silver birch seedlings, respectively. Significant differences due to UV exclosure treatments were determined for the NR activity of silver birch seedlings (F = 3.62, P= 0.025*) after three growing seasons (191 days) of UV exclusion. The ambient and control silver birch seedlings had or tended to have higher NR activity than those grown under UV exclusion. No relationship was found between the foliage NR activity and total nitrogen content, which ranged from 0.61 to 1.35% per seedling. The present study suggests large differences in NR activity between the species and the induction of NR activity in silver birch seedlings due to ambient UV radiation.
authors.affiliation: Institute of Botany, Polish Academy of Sciences, Krakow.
authors.forename: Marek
authors.initials: M
authors.lastname: Krywult
authors.forename: Minna
authors.initials: M
authors.lastname: Turunen
authors.forename: Marja-Liisa
authors.initials: ML
authors.lastname: Sutinen
authors.forename: Kirsti
authors.initials: K
authors.lastname: Derome
authors.forename: Yrjö
authors.initials: Y
authors.lastname: Norokorpi
mesh_terms: D000222:Adaptation, Physiological; D029662:Betula / Q000201:enzymology*; D004777:Environment; D004781:Environmental Exposure; D050901:Nitrate Reductase; D009565:Nitrate Reductases / Q000378:metabolism*; D028201:Pinaceae / Q000201:enzymology*; D018515:Plant Leaves / Q000201:enzymology; D010944:Plants / Q000201:enzymology; D014466:Ultraviolet Rays / Q000009:adverse effects*; D029800:Vaccinium myrtillus / Q000201:enzymology*
chemical_list: D009565:Nitrate Reductases; D050901:Nitrate Reductase