Lead effects on cereal roots in terms of cell growth, root architecture and metal accumulation

The influence of lead nitrate on root growth of maize and barley seedlings was studied in terms of cell growth analysis with respect to root system morphology, lead accumulation and distribution among plant organs. At growth-inhibiting 10−3 M concentration in Petri dishes, lead nitrate retarded by half root extension, but did not affect the number of lateral or seminal roots that resulted in the modified root architecture, i.e. shorter and more compact root system. Lead unspecifically inhibited cell division and cell elongation. It was accumulated by root mainly in slime, rhizodermis and cortex, but almost did not penetrate endodermis that prevents lead translocation to shoots and explains not only its low content in shoots and ears, but weak and delayed effect on shoot growth as well. This barrier role of root system is emphasized.