Ecological significance of assimilate distribution in Agropyron repens clones under influence of the copper smelter Legnica

Abstract

The studies on couch grass (Agropyron repens (L.) P. Beauv.) populations growing in stress conditions in close vicinity of a copper smelter concern the integrity of clonal structure. The connections of tillers within a clone and the interclonal integrity was investigated by means of assimilate translocation, using ¹⁴C. It was found that heavy metal stress affects the phenotypic plasticity of couch grass in regard to clonal growth of the phalanx type. The phalanx type growth is supported by a considerable integration, which allows the redistribution of resources, through internal routes, from places rich in resources to such clone parts, which cover a surface poor in nutritive compounds. In an unpolluted (control) couch grass population representing the guerilla type of growth, the translocation of assimilates concerns only the closest (sister) ramets. The phalanx type of growth in couch grass subjected to contamination favours also the accumulation of organic matter and macronutrients (N, Ca) in zones of occurrence of Agropyron repens clusters, which are in deficit in areas close to the smelter. The irregular accumulation of heavy metals and the deficit of macronutrients in soil, form near the smelter a patchy environment. In this patchy environment couch grass, as one of few plants, finds appropriate conditions for foraging. The whole of factors in the studied polluted area creates a unique dynamic system between couch grass clones and the local ecological conditions.