Investigation of Spatial and Temporal Patterns of 137Cs Partitioning in Eriophorum Vaginatum L. in Relation to its Nutrient Retrieval and Storage Strategy

Abstract

Relatively high levels of 137Cs from the Chernobyl accident in indigenous vegetation in infertile upland habitats in the UK have been partly attributed to strategies that permit efficient use of limited nutrient resources. This study investigated temporal and spatial patterns of 137Cs allocation in Eriophorum vaginatum L. (hare’s-tail cotton-grass) in relation to its nutrient retrieval and storage strategy. Plants were labelled with 137Cs via root uptake in April 1995 and dissected components were analysed on six occasions over the following 16 months. 137Cs remained relatively mobile in the plants and was re-circulated to new leaves and roots that were initiated after the labelling event. The retrieval of 137Cs from maturing leaves was less efficient than that documented for K and this represented a significant loss process of 137Cs from the biomass. A greater loss of 137Cs occurred through the roots. Consequently, successively produced leaves contained progressively less 137Cs and an exponential decline in the maximum pool of 137Cs (i.e. the maximum accumulation of 137Cs activity measured in a leaf) in successively produced leaves was observed. This study provides direct evidence that strategies that minimise nutrient losses and permit efficient use of limited nutrient resources in deciduous graminoids also prolong the presence of 137Cs in the vegetation of E. vaginatum.