Critical concentration of cadmium in soil and toxicity symptoms in corn plants (Zea mays L.)

摘要

Determination of toxic concentration of metals in soils is needed to support legislations on soil pollution by trace metals. High concentrations of metals in plants are generally associated with visual symptoms of toxicity and anatomical alterations at cellular level. The work was carried out to determine the critical toxic concentration of cadmium (Cd) in an Ultisol cultivated with corn (Zea mays L.) and its relation to toxicity symptoms. Plants were grown for 30 days in pots containing five rates of Cd (0, 1, 3, 5, 10 and 20mg·kg<'-1>) added as CdCl<,2> solution. The critical concentration of Cd in soil, which caused a 30% reduction in dry matter production, was 10mg·kg<'-1>. Chlorotic and coiled leaves were the most common visual symptoms of Cd toxicity. Increased lignification of the cell wall in several cell tissues was also observed.