Untersuchungen zurn Schwermetallhaushalt von Phaseolus vulgaris L. bei Belastung mit NiSO4 bzw. NiEDTA

Abstract

Bush beans (Phaseolus vulgaris L. var. Saxa) were grown in nutrient solutions containing different levels of NiSO4 and NiEDTA, respectively. With respect to the Ni treatments, Fe was given as FeC13 and FeEDTA, respectively. After 10 days the plants were dissected into leaves, stems, and roots. To remove adsorptively bound cations the roots were washed in 0.1 N HCl and deionized water. After drying, the material was prepared by wet digestion for analysis by atomic absorption spectroscopy. There were 3 replicates. The results indicated that Ni content in all organs increased when the Ni concentration in the nutrient solution increased. This was observed in both cases, when treated either with NiSO4 or NiEDTA. However, there was a significant difference concerning the amount of Ni accumulation. E.g., the highest NiSO4 concentration of 300 µM resulted in values of 606±85 (leaves), 815±73 (stems), and 770±109 (roots) µg Ni g-1 dry matter, whereas equimolar NIEDTA treatments caused Ni contents of only 130±12 (leaves), 115±32 (stems), and 127±21 (roots) Pg Ni gt dry matter. Thus, by chelating agent Ni content was reduced by about 5 times. Furthermore the data prove that within the plant Ni is mobile. The micronutrients Fe, Cu, Mn, and Zn were affected by the NiSO4 and NiEDTA treatments in a different manner. Whereas the Fe content of each part of the plant was higher by application of NiEDTA than of NiSO4, Cu content was unaffected in leaves and stems, but lowered in the roots, and Mn and Zn levels were reduced in all organs, especially in the roots. Whereas increasing NiEDTA concentrations in the nutrient solution caused no difference in the level of any micronutrient, increasing N'S04 treatments lowered Mn and Zn content of each organ of the plant, but did not affect significantly Fe or Cu levels. The dissimilar effect of NiSO4 and NiEDTA treatments with respect to the micronutrients seems to be due to the differing Ni accumulation in the NiSO4 and NiEDTA series.