A comparison of caesium uptake kinetics in eight species of grass

Abstract

The Michaelis–Menten kinetic parameters ( I max , K m and C min) of Cs uptake were estimated using a solution-depletion method, after 0, 1 and 4 d K-starvation in eight mature grass species of different relative growth rates ( Bromus sterilis L., Elymus repens (L.) Gould, Poa annua L., Lolium perenne L. var. ‘Taya’, Anthoxanthum odoratum L., Festuca gigantea (L.) Vill., Festuca ovina L. and Nardus stricta L.). There were species differences in I max and C min, a positive relationship between K m and RGR ( r 2=0.53; p=0.03), and a negative relationship between C min and RGR ( r 2=0.89; p=0.001) in 0 d K starved plants. In general, I max increased with K starvation, as previously reported for K uptake kinetics. K m increased with K starvation, contrasting with reported studies on K, and C min decreased, although all species did not respond similarly.