Uso do silício na redução da toxidez de zinco em mudas de eucalipto

Abstract

Industrial growth has led to soil contamination by different heavy metals that constitute a problem for the normal development of several plants species. Among such metals, zinc (Zn) has a toxic potential when found in high levels in the soil. On the other hand, silicon (Si) can alleviate the toxic effects of metals on plants. The objective of this study was to evaluate the dry matter production and anatomical changes in roots of Eucalyptus urophylla seedlings under various concentrations of Zn in the presence or absence of Si in the nutrient solution. Seedlings of E. urophylla were cultivated in pots containing 3l of Clark nutritive solution (pH 5,5) in a randomized 6´2 factorial design, with six Zn levels (0, 2, 50, 150, 300 and 400µmol·l-1), with and without silicon (0 and 1.78mmol·l-1). After eight weeks the dry matter production of shoots and roots, macro and micronutrients, Si concentration, translocation indices and the root s anatomy were evaluated. Si addition to the solution did not influence the negative effect of Zn on dry matter production of E. urophylla. In general, the concentration had little influence on the concentration and translocation index of the evaluated nutrients. The anatomic alterations caused by the excess Zn were smaller when Si was added to the solution.