The uptake of potassium by <i>Carex</i> species from swamp habitats varying from oligotrophic to eutrophic

Abstract

Short‐term potassium uptake by excised roots was investigated in Carex species from swamps, ranging from oligotrophic to eutrophic. The range of species from oligotrophic to eutrophic habitat is: C. rostrata Stokes, C. limosa L., C. lasiocarpa Ehrh., C. diandra Schrank, C. hudsonii A. Benn., and C. acutiformis Ehrh. After a short period of potassium starvation the species of the oligotrophic habitat showed a fast potassium uptake rate while the species of the eutrophic habitat showed lower uptake rates. Uptake by all species except C. rostrata and C. diandra was reduced at pH 4.0. Potassium uptake at low potassium concentrations was greatly increased by a period of starvation for potassium especially in the eutrophic species. The results on potassium stress are compared with the ecology of the species and with the reaction of the same Carex species to phosphate stress.