Anomalous scales of Tillandsia usneoides (L.) L. (Bromeliaceae) exposed in the Metropolitan Region of Campinas, SP, Brazil as air pollution markers

Tillandsia usneoides is an epiphytic bromeliad that has been used as a universal bioindicator. The species accumulates metals and presents foliar scale variations when exposed to air pollutants. This study aimed to use the variations in foliar scales as microscopic markers of pollutant effects in the Metropolitan Region of Campinas (MRC), São Paulo State, Brazil. T. usneoides plants were exposed for 12 weeks during dry and wet seasons, totaling four exposures, at five sites in the MRC. Samples were selected before each exposure for initial evaluation of the plants (T0). Leaf fragments were fixed in glutaraldehyde and total scale density and anomalous scale percentage were evaluated. Plants exposed in the MRC showed anomalies and changes in number of subperipheral cells of leaf scales. When compared to T0, T. usneoides presented higher total scale density and anomalous scale percentage at disturbed sites, thus the species can be used as a pollution bioindicator for MRC.