MICROANALYTICAL INVESTIGATION OF XYLEM SAP OF CUCUMBER BY TOTAL-REFLECTION X-RAY-FLUORESCENCE SPECTROMETRY

Concentrations of essential elements (K, Ca, Cu, Fe, Mn, Zn) and toxic lead in xylem fluid of cucumber plants growing in lead-free and lead- contaminated nutrient solutions were determined by total reflection X- ray fluorescence spectrometry. Amounts of essential elements transport ed in xylem during the bleeding period are lower by a factor of 1.1-1. 4 for lead-contaminated plants with the exception of manganese. Its tr ansport increases in the presence of lead contamination by a factor of 1.3. This observation was also confirmed by inductively coupled plasm a atomic emission spectrometry of plant parts (leaves, stems) after th eir microwave dissolution. (C) 1997 Academic Press.