The physiological response of Eucalyptus rostrata due to exposure to
heavy metal air pollutants was investigated. The heavy metals Cu, Cd,
Fe, and Pb were applied to the above ground parts of the plants, under
greenhouse conditions. The metal contents were proportional to the
metal concentration in the sprayed solutions. Increasing sprayed metal
concentrations was found to have an important effect to develop
phytotoxicity signs with Cu, Cd and Pb. With the metal concentration
increment, a sharp increase in the specific leaf area (P<0.05) from
control was detected. The dry mass and leaf water content showed
narrow variations among the different concentrations of the same metal
and metal species varied significantly in their effects. The
metal-pigment analysis showed a significant pigment reduction
(P<0.01) with increasing metal concentration in the sprayed solution.
In comparison with control, treated leaves exhibited substantial
decrease in their total chlorophyll and chlorophyll a/b ratio. The
increase of proline content and relative peroxidase activity provides an
evident proof on the physiological response and the pollution impact
caused by the heavy metals application on the investigated species.