Interactions of nitrogen sources and excess nickel on bush beans

Bush bean (Phaseolus vulgaris L. cv. Improved Tendergreen) plants were grown in a glasshouse in 3700 ml nutrient solutions for 15 days with three nitrogen sources and different levels of NiSO4. All NH4 + and urea treatments received CaCO3 (10 g/3700 ml) in the nutrient solution to protect against excess acidity. In general, plants receiving the NH4 + source of N had less growth than those receiving urea or NO3 ‐ and 5 X 10‐4 M Ni treatments greatly inhibited growth. There was, however, no indication of interactions of N source and Ni on yield. Plants receiving NH4 + and urea had higher Ni concentrations than NO3 ‐ plants. Nickel resulted in decreased Fe in trifoliate leaves but not in primary leaves and the reverse occurred in roots. There was no interaction of Ni and Fe in roots but there was a Mh‐Ni‐N‐source interaction in roots.