Estudo sobre os efeitos do cobre e zinco no crescimento da plântula de "Aechmea blanchetiana" (BAKER) L. B. Smith cultivada "in vitro". Aplicação da análise por ativação com nêutrons

Abstract

Metals are components of the biosphere, occurring naturally in soil and plants, but as a result of human actions, their levels have been greatly increased, depending on the region. Copper (Cu) and zinc (Zn) are essential for the growth and development of plants, however if in excess become toxic. The aim of this study was to evaluate the potential of plants to absorb Cu and Zn and what effects they cause in seedlings cultivated in vitro. The results of this study may contribute primarily in agricultural and environmental research. The plant investigated was the Aechmea blanchetiana species of the Bromeliaceae family. It is a terrestrial or epiphytic species used as an ornamental plant. The cultivation of seedlings for this study and their exposure to different concentrations of Cu and Zn were performed at the Institute of Botany (IBt) of São Paulo. After seed germination, the seedlings were transferred for growth in a culture media containing different concentrations of Cu or Zn. After this period of in vitro cultivation, the seedlings were analyzed for morphometry, anatomy and by neutron activation analysis. Quality control of the results from neutron activation analysis was carried out by the analysis of certified reference materials. The data obtained showed good precision and accuracy for several elements determined. The highest concentrations of Cu used in the exposure were those that caused major structural changes in morphometric and anatomical parameters, however for the Zn no significant differences were verified for most parameters. The A. blanchetiana proved to be a bioaccumulator species of Zn, absorbing high levels of this element in the aerial parts and roots.