J. Environ. Radioactivity, Vol. 40, No. 2, pp. 175 — 184, 1998 ( 1998 Elsevier Science Ltd. All rights reserved Printed in Great Britain PII: S0265-931X(97)00074-X 0265-931X/98 $19.00#0.00 134 Cs in Heather Seed Plants Grown With and Without Mycorrhiza Morten Strandberg a, * & Marianne Johansson b a Ris+ National Laboratory, DK-4000 Roskilde, Denmark b Department of Mycology, Botanical Institute, University of Copenhagen, "ster Farimagsgade 2D, DK-1353 Copenhagen K. Denmark (Received 3 March 1997; accepted 29 September 1997) ABS¹RAC¹ Experiments were carried out to determine differences between mycorrhized and non-mycorrhized seed plants of heather, Calluna vulgaris(¸)Hull, as regards the uptake of 134 Cs. In most treatments heather with mycorrhiza had a significantly higher transfer of 134 Cs to the shoots than heather without mycorrhiza. As an average the concentration of 134 Cs was 18% higher in the mycorrhized plants than in the non-mycorrhized. Application of 10 kg K/ha reduced the concentration of 134 Cs in shoots of heather by 49% as an average. Because of improved growth in the potassium fertilized pots the reduction viewed on the basis of the area was only 33%. Nitrogen application does not significantly influence the concentration of 134 Cs in shoots of heather regard- less of mycorrhizal status. ( 1998 Elsevier Science Ltd. All rights reserved INTRODUCTION Heather (Calluna vulgaris (L.) Hull) is an important species in heathland in the oceanic parts of Europe, with the main distribution between France and the Faroe Islands and Sweden and Great Britain, respectively, latitudinally and longitudinally (Gimingham, 1972). In the main part of the distribution area heather is associated with poor, sandy and acidic soils with a high * Corresponding author; present address: Morten Strandberg, National Environmental Research Institute, Vejls+vej 25, 8600 Silkeborg. E-mail: mts@dmu.dk33. 175