Silver uptake, distribution, and effect on calcium, phosphorus, and sulfur uptake

Bean, corn, and tomato plants were grown in a nutrient solution labeled with (32)P, (45)Ca, or (35)S and varying concentrations of AgNO(3). Following a 6-hour treatment period, plants were harvested and analyzed. A low Ag(+) concentration (50 nanomolar) inhibited the shoot uptake of the ions investigated. In the roots, Ca uptake increased whereas P and S uptake decreased.Autoradiograms of bean and corn plants, using (110m)Ag, showed that Ag(+) was uniformly deposited in the bean shoot, but corn shoots had regions of high activity along the leaf margins and at the tips where guttation had occurred. Roots were heavily labeled and shoots (especially the new growth) continued to accumulate Ag(+) even after the intact plant was returned to Ag-free solution. Silver was believed to be phloem-mobile since it was exported from a treated leaf. Bean plants removed one-half the Ag(+) from 4 liters of nutrient solution containing 50 nanomolar AgNO(3) within 1.5 hours, but took 16 hours for 20 liters of solution.