X-RAY MICROANALYSES IN ROOTS OF AL-TREATED AVENA-SATIVA PLANTS

The uptake and localization of aluminium in root tissues as well as th e effect of Al-stress on intracellular concentrations of phosphate and potassium were analysed by X-ray microanalysis (EDXA). Al is predomin antly localized in the cell walls of peripheral cells, and is only ver y slowly translocated to more central tissues. The plasma membrane is a very effective barrier against Al-influx into the cells, so that 24 h after onset of Al-treatment no intracellular detection of Al was pos sible. Furthermore, during a 10-day period of Al-treatment, Al was not accumulated in the nuclei of meristematic root tissues. Although in t he cell wall Al is partially precipitated as aluminium phosphate, this causes no P-depriviation of root cells. Likewise, the K-uptake and tr ansport into the stele is not affected by Al-stress.