title: The use of light and electron microscopy to assess the impact of ozone on Norway spruce needles.
abstract: Light (LM) and transmission electron (TEM) microscopy were used to study previously specified ozone symptoms in the foliage of Norway spruce. The three youngest green needle generations from twenty mature trees in two stands on sites of different soil fertility at Asa, southern Sweden, were sampled in 1999. The critical dose of ozone, expressed as AOT40, was 6,362 ppb.h. LM showed ozone-specific symptoms: decreased chloroplast size with electron dense stroma advancing gradually from the outer to the inner cell layers, being most severe in the needle side facing the sky. The symptoms were expressed as ozone syndrome indices at the needle generation, tree and stand levels. The index had higher values at the low fertility site. TEM was used to confirm the LM results. The study shows that LM can be used for diagnosis of the impact of ozone on conifers in the field.
authors.affiliation: Department of Ecology and Environmental Science, University of Kuopio, PO Box 1627, FIN-70211 Kuopio, Finland. minna.kivimaenpaa@uku.fi
authors.forename: Minna
authors.initials: M
authors.lastname: Kivimäenpää
authors.forename: Anna Maria
authors.initials: AM
authors.lastname: Jönsson
authors.forename: Ingrid
authors.initials: I
authors.lastname: Stjernquist
authors.forename: Gun
authors.initials: G
authors.lastname: Selldén
authors.forename: Sirkka
authors.initials: S
authors.lastname: Sutinen
mesh_terms: D000393:Air Pollutants / Q000633:toxicity*; D004784:Environmental Monitoring / Q000379:methods*; D008452:Maximum Allowable Concentration; D008854:Microscopy, Electron; D010126:Ozone / Q000633:toxicity*; D028222:Picea / Q000033:anatomy & histology / Q000187:drug effects*; D018515:Plant Leaves / Q000187:drug effects* / Q000648:ultrastructure; D013548:Sweden
chemical_list: D000393:Air Pollutants; D010126:Ozone