Dry matter and leaf structure in young wheat plants as affected by cadmium, lead, and nickel

The effects of 1 mM cadmium, lead and nickel on dry mass, Cd, Pb, and Ni co ntents, and changes in leaf structure in young wheat plants were studied. I n leaves, Cd content was highest, followed by Pb and Ni, in roots Cd conten t was also highest, but followed by Ni and Pb. Roots accumulated considerab ly larger amounts of the three heavy metals than leaves. Largest reductions of leaf and root mass were obtained with Cd. Pb and Ni effects were almost equal. Ni excess had a strong negative effect on mesophyll thickness, whil e Cd mostly reduced the number and size of vascular bundles and vessel diam eter. High Pb reduced the diameter of vessels causing their different defor mations.