Effects on growth and uptake of broad beans (Vicia fabae L.) by root and foliar treatments of plant with lead and cadmium

Abstract
Uptake of toxic metals by plants has been of great interest to environmental scientists because this might harm the growth of plant and cause health hazard to man and animal. In this study, the effects of two elements (lead and cadmium) which cause high concern because of their cummulative nature have been studied on broad beans. Both elements have been found to affect the growth of broad beans and this effect increased with the increase of concentration of metal in solutions used for root‐treatment or for foliar‐treatment of plant. The effect of foliar‐treatment was very much higher than the effect of root‐treatment by lead or cadmium. Cadmium was found more toxic to plant growth than lead. The effect of cadmium treatment was more on the growth of fruits while the effect of lead treatment was more on the roots of broad beans. The least affected part by lead or cadmium was the stem of plant. Both the concentration and the whole content of metal in plants and its varoius parts (roots, stem, leaves and fruits) increased steadily with the increase of cadmium or lead concentration in solutions used for either root‐treatment or foliar‐treatment. Concentration of metal ions was higher in roots and leaves than in fruits and stems of treated plants. The uptake of metal to plant was calculated to be a very small part of the total amount of metal added during treatment. Some explanations have been suggested in this study to explain the results obtained.