Effect of external potassium (K) supply on the uptake of 137Cs by spring wheat (Triticum aestivum cv. Tonic): a large-scale hydroponic study.
A large-scale hydroponic experiment was carried out in a non-controlled greenhouse. Spring wheat plants were grown to maturity at four levels of external K concentration (2, 4, 20 and 40 mgl(-1)) and one concentration of radiocaesium (8 Bqml(-1)). Concentrations of K and radiocaesium in the growth solution were closely monitored, and replenishments were made upon depletion. K effectively competed with radiocaesium in terms of root uptake. Activity concentrations of radiocaesium in plants differed significantly between the four K treatments; the activity concentration at the lowest external K concentration being 100 times higher than that at the highest K level. The relationship between radiocaesium uptake and external K level could be described by a negative power function; this showed that when the K level reached around 12 mgl(-1), further increases in the external K level resulted only in slight changes in its inhibitory effect. As a result of this inhibitory effect of potassium supply, concentrations of radiocaesium in plant tissues, grains in particular, were greatly reduced at high external K concentration. Mechanisms involved in Cs-K interaction in root uptake are also discussed.
Zhu
Y G
YG
T.H. Huxley School of Environment, Earth Science and Engineering, Imperial College of Science Technology and Medicine, Ascot, Berks, UK. yongguan.zhu@adelaide.edu.au
D000704:Analysis of Variance; D002588:Cesium Radioisotopes / Q000378:metabolism*; D018527:Hydroponics / Q000379:methods; D011188:Potassium / Q000494:pharmacology*; D012990:Soil Pollutants, Radioactive; D014908:Triticum / Q000254:growth & development / Q000378:metabolism*
D002588:Cesium Radioisotopes; D012990:Soil Pollutants, Radioactive; D011188:Potassium