Effects of copper and nickel on subarctic Scots pine needles

• Main Author: Kukkola, E. (Eija)
• Format: Doctoral or Postdoctoral Thesis
• Language: English
• Published: University of Oulu 1999
• Subjects: air pollutants; metal indications; ultrastructure; Pinus sylvestris L; Kola Peninsula; Kevo; The Needles; Monchegorsk; kola peninsula; Subarctic
• Online Access: http://urn.fi/urn:isbn:9514253701

Abstract Three different studies were conducted to elucidate the effects of copper (Cu) and nickel (Ni) on Scots pine needles. One was the Monchegorsk smelter emission gradient study on the Kola Peninsula, Russia, the second was the 3-year seedling and 6-year adult tree low-level CuNi and acid rain (H2SO4 at pH 3) irrigation study at Kevo, Finland. In the third study seedlings were exposed to Cu and Ni for a one season in Oulu, Finland. Ni accumulated efficiently in needles, and this accumulation was seen in each of the different studies. The Cu concentrations remained low in needles, except near the Monchegorsk smelters. The addition of Ni together with Cu in Oulu seemed to enhance the accumulation of Ni into the needles of Scots pine seedlings. Plasmolysis may be related to both drought and the Ni treatment, as observed in Oulu, because plasmolysis was statistically more abundant in the 15 mg Ni kg-1 dry soil treated needles than in other treatments except in 25 mg Ni kg-1 dry soil. Cu induced lipid peroxidation of chloroplast membranes was visible under transmission electron microscope (TEM) as light colored, swollen thylakoids in chloroplasts near the Monchegorsk smeltersand also in needles exposed to 25 Ni+50 Cu mg kg-1 in soil in Oulu. Some year to year variation in the frost hardening process was seen in metal and acid treated needles, which may have caused the maximum frost hardiness level drop after CuNi, pH3 and CuNi/pH3 treatments. Root growth was increased by 5 mg Ni kg-1 dry soil in soil in Oulu, but 15 mg Ni kg-1 dry soil Ni in soil decreased root growth and increased root tip dieback. 25 Ni+50 Cu mg kg-1 dry soil in soil markedly decreased root growth. The proportion of oxidized glutathione in Cu-treated needles was smaller than in Ni-treated needles, but roots had higher peroxidase activity levels. However, Ni seemed to cause more oxidative stress to seedlings than copper.